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Glossary of WSA attributes

This Glossary alphabetically lists all attributes used in the UKIDSSDR10 database(s) held in the WSA. If you would like to have more information about the schema tables please use the UKIDSSDR10 Schema Browser (other Browser versions).
A B C D E F G H I J K L M
N O P Q R S T U V W X Y Z

J

NameSchema TableDatabaseDescriptionTypeLengthUnitDefault ValueUnified Content Descriptor
j_1AperMag3 lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Default point/extended source 1st epoch J aperture corrected mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
j_1AperMag3 lasSource WSA Default point/extended source 1st epoch J aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator		 real 4 mag -0.9999995e9 PHOT_MAG
j_1AperMag3Err lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in default point/extended source 1st epoch J mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
j_1AperMag4 lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 1st epoch J aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
j_1AperMag4Err lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 1st epoch J mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
j_1AperMag6 lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 1st epoch J aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
j_1AperMag6Err lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 1st epoch J mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
j_1Class lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA discrete image classification flag in 1st epoch J smallint 2   -9999 CLASS_MISC
j_1ClassStat lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA N(0,1) stellarness-of-profile statistic in 1st epoch J real 4   -0.9999995e9 STAT_PROP
j_1Deblend lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA placeholder flag indicating parent/child relation in 1st epoch J int 4   -99999999 CODE_MISC
j_1Deblend lasSource WSA placeholder flag indicating parent/child relation in 1st epoch J int 4   -99999999 CODE_MISC
This CASU pipeline processing source extraction flag is a placeholder only, and is always set to zero in all passbands in the merged source lists. If you need to know when a particular image detection is a component of a deblend or not, test bit 4 of attribute ppErrBits (see corresponding glossary entry) which is set by WFAU's post-processing software based on testing the areal profiles aprof2-8 (these are set by CASU to -1 for deblended components, or positive values for non-deblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables.
j_1Ell lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA 1-b/a, where a/b=semi-major/minor axes in 1st epoch J real 4   -0.9999995e9 PHYS_ELLIPTICITY
j_1eNum lasMergeLog, lasYJHKmergeLog WSA the extension number of this 1st epoch J frame tinyint 1     NUMBER
j_1ErrBits lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA processing warning/error bitwise flags in 1st epoch J int 4   -99999999 CODE_MISC
j_1ErrBits lasSource WSA processing warning/error bitwise flags in 1st epoch J int 4   -99999999 CODE_MISC
Apparently not actually an error bit flag, but a count of the number of zero confidence pixels in the default (2 arcsec diameter) aperture.
j_1Eta lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Offset of 1st epoch J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
j_1Eta lasSource WSA Offset of 1st epoch J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
j_1Gausig lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA RMS of axes of ellipse fit in 1st epoch J real 4 pixels -0.9999995e9 MORPH_PARAM
j_1HallMag lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Total point source 1st epoch J mag real 4 mag -0.9999995e9 PHOT_MAG
j_1HallMagErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in total point source 1st epoch J mag real 4 mag -0.9999995e9 ERROR
j_1Mag lasSourceRemeasurement WSA 1st epoch J mag (as appropriate for this merged source) real 4 mag -0.9999995e9 PHOT_MAG
j_1MagErr lasSourceRemeasurement WSA Error in 1st epoch J mag real 4 mag -0.9999995e9 ERROR
j_1mfID lasMergeLog, lasYJHKmergeLog WSA the UID of the relevant 1st epoch J multiframe bigint 8     ID_FRAME
j_1mhExt lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Extended source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
j_1mhExt lasSource WSA Extended source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
j_1mhExtErr lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Error on extended source colour J-H real 4 mag -0.9999995e9 ERROR
j_1mhExtErr lasSource WSA Error on extended source colour J-H real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
j_1mhPnt lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Point source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
j_1mhPnt lasSource WSA Point source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
j_1mhPntErr lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Error on point source colour J-H real 4 mag -0.9999995e9 ERROR
j_1mhPntErr lasSource WSA Error on point source colour J-H real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
j_1ObjID lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA DEPRECATED (do not use) bigint 8   -99999999 ID_NUMBER
j_1ObjID lasSource, lasSourceRemeasurement WSA DEPRECATED (do not use) bigint 8   -99999999 ID_NUMBER
This attribute is included in source tables for historical reasons, but it's use is not recommended unless you really know what you are doing. In general, if you need to look up detection table attributes for a source in a given passband that are not in the source table, you should make an SQL join between source, mergelog and detection using the primary key attribute frameSetID and combination multiframeID, extNum, seqNum to associate related rows between the three tables. See the Q&A example SQL for more information.
j_1PA lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA ellipse fit celestial orientation in 1st epoch J real 4 Degrees -0.9999995e9 POS_POS-ANG
j_1PetroMag lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 1st epoch J mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
j_1PetroMagErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 1st epoch J mag (Petrosian) real 4 mag -0.9999995e9 ERROR
j_1ppErrBits lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA additional WFAU post-processing error bits in 1st epoch J int 4   0 CODE_MISC
j_1ppErrBits lasSource WSA additional WFAU post-processing error bits in 1st epoch J int 4   0 CODE_MISC
Post-processing error quality bit flags assigned (NB: from UKIDSS DR2 release onwards) in the WSA curation procedure for survey data. From least to most significant byte in the 4-byte integer attribute byte 0 (bits 0 to 7) corresponds to information on generally innocuous conditions that are nonetheless potentially significant as regards the integrity of that detection; byte 1 (bits 8 to 15) corresponds to warnings; byte 2 (bits 16 to 23) corresponds to important warnings; and finally byte 3 (bits 24 to 31) corresponds to severe warnings:
ByteBitDetection quality issue Threshold or bit mask Applies to
DecimalHexadecimal
0 4 Deblended 16 0x00000010 All VDFS catalogues
0 6 Bad pixel(s) in default aperture 64 0x00000040 All VDFS catalogues
1 15 Source in poor flat field region 32768 0x00008000 All but mosaics
2 16 Close to saturated 65536 0x00010000 All VDFS catalogues (though deeps excluded prior to DR8)
2 17 Photometric calibration probably subject to systematic error 131072 0x00020000 GPS only
2 19 Possible crosstalk artefact/contamination 524288 0x00080000 All but GPS
2 22 Lies within a dither offset of the stacked frame boundary 4194304 0x00400000 All but mosaics

In this way, the higher the error quality bit flag value, the more likely it is that the detection is spurious. The decimal threshold (column 4) gives the minimum value of the quality flag for a detection having the given condition (since other bits in the flag may be set also; the corresponding hexadecimal value, where each digit corresponds to 4 bits in the flag, can be easier to compute when writing SQL queries to test for a given condition). For example, to exclude all K band sources in the LAS having any error quality condition other than informational ones, include a predicate ... AND kppErrBits ≤ 255. See the SQL Cookbook and other online pages for further information.
j_1PsfMag lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Point source profile-fitted 1st epoch J mag real 4 mag -0.9999995e9 PHOT_MAG
j_1PsfMagErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in point source profile-fitted 1st epoch J mag real 4 mag -0.9999995e9 ERROR
j_1SeqNum lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA the running number of the 1st epoch J detection int 4   -99999999 ID_NUMBER
j_1SeqNum lasSourceRemeasurement WSA the running number of the 1st epoch J remeasurement int 4   -99999999 ID_NUMBER
j_1SerMag2D lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 1st epoch J mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
j_1SerMag2DErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 1st epoch J mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
j_1Xi lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Offset of 1st epoch J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
j_1Xi lasSource WSA Offset of 1st epoch J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
j_2AperMag3 lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Default point/extended source 2nd epoch J aperture corrected mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
j_2AperMag3 lasSource WSA Default point/extended source 2nd epoch J aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator		 real 4 mag -0.9999995e9 PHOT_MAG
j_2AperMag3Err lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in default point/extended source 2nd epoch J mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
j_2AperMag4 lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 2nd epoch J aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
j_2AperMag4Err lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 2nd epoch J mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
j_2AperMag6 lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 2nd epoch J aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
j_2AperMag6Err lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 2nd epoch J mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
j_2Class lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA discrete image classification flag in 2nd epoch J smallint 2   -9999 CLASS_MISC
j_2ClassStat lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA N(0,1) stellarness-of-profile statistic in 2nd epoch J real 4   -0.9999995e9 STAT_PROP
j_2Deblend lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA placeholder flag indicating parent/child relation in 2nd epoch J int 4   -99999999 CODE_MISC
j_2Deblend lasSource WSA placeholder flag indicating parent/child relation in 2nd epoch J int 4   -99999999 CODE_MISC
This CASU pipeline processing source extraction flag is a placeholder only, and is always set to zero in all passbands in the merged source lists. If you need to know when a particular image detection is a component of a deblend or not, test bit 4 of attribute ppErrBits (see corresponding glossary entry) which is set by WFAU's post-processing software based on testing the areal profiles aprof2-8 (these are set by CASU to -1 for deblended components, or positive values for non-deblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables.
j_2Ell lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA 1-b/a, where a/b=semi-major/minor axes in 2nd epoch J real 4   -0.9999995e9 PHYS_ELLIPTICITY
j_2eNum lasMergeLog, lasYJHKmergeLog WSA the extension number of this 2nd epoch J frame tinyint 1     NUMBER
j_2ErrBits lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA processing warning/error bitwise flags in 2nd epoch J int 4   -99999999 CODE_MISC
j_2ErrBits lasSource WSA processing warning/error bitwise flags in 2nd epoch J int 4   -99999999 CODE_MISC
Apparently not actually an error bit flag, but a count of the number of zero confidence pixels in the default (2 arcsec diameter) aperture.
j_2Eta lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Offset of 2nd epoch J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
j_2Eta lasSource WSA Offset of 2nd epoch J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
j_2Gausig lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA RMS of axes of ellipse fit in 2nd epoch J real 4 pixels -0.9999995e9 MORPH_PARAM
j_2HallMag lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Total point source 2nd epoch J mag real 4 mag -0.9999995e9 PHOT_MAG
j_2HallMagErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in total point source 2nd epoch J mag real 4 mag -0.9999995e9 ERROR
j_2Mag lasSourceRemeasurement WSA 2nd epoch J mag (as appropriate for this merged source) real 4 mag -0.9999995e9 PHOT_MAG
j_2MagErr lasSourceRemeasurement WSA Error in 2nd epoch J mag real 4 mag -0.9999995e9 ERROR
j_2mfID lasMergeLog, lasYJHKmergeLog WSA the UID of the relevant 2nd epoch J multiframe bigint 8     ID_FRAME
j_2mrat twomass_scn 2MASS J-band average 2nd image moment ratio. real 4     FIT_PARAM_VALUE
j_2mrat twomass_sixx2_scn 2MASS J band average 2nd image moment ratio for scan real 4      
j_2ObjID lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA DEPRECATED (do not use) bigint 8   -99999999 ID_NUMBER
j_2ObjID lasSource, lasSourceRemeasurement WSA DEPRECATED (do not use) bigint 8   -99999999 ID_NUMBER
This attribute is included in source tables for historical reasons, but it's use is not recommended unless you really know what you are doing. In general, if you need to look up detection table attributes for a source in a given passband that are not in the source table, you should make an SQL join between source, mergelog and detection using the primary key attribute frameSetID and combination multiframeID, extNum, seqNum to associate related rows between the three tables. See the Q&A example SQL for more information.
j_2PA lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA ellipse fit celestial orientation in 2nd epoch J real 4 Degrees -0.9999995e9 POS_POS-ANG
j_2PetroMag lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 2nd epoch J mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
j_2PetroMagErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 2nd epoch J mag (Petrosian) real 4 mag -0.9999995e9 ERROR
j_2ppErrBits lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableLasPointSource WSA additional WFAU post-processing error bits in 2nd epoch J int 4   0 CODE_MISC
j_2ppErrBits lasSource WSA additional WFAU post-processing error bits in 2nd epoch J int 4   0 CODE_MISC
Post-processing error quality bit flags assigned (NB: from UKIDSS DR2 release onwards) in the WSA curation procedure for survey data. From least to most significant byte in the 4-byte integer attribute byte 0 (bits 0 to 7) corresponds to information on generally innocuous conditions that are nonetheless potentially significant as regards the integrity of that detection; byte 1 (bits 8 to 15) corresponds to warnings; byte 2 (bits 16 to 23) corresponds to important warnings; and finally byte 3 (bits 24 to 31) corresponds to severe warnings:
ByteBitDetection quality issue Threshold or bit mask Applies to
DecimalHexadecimal
0 4 Deblended 16 0x00000010 All VDFS catalogues
0 6 Bad pixel(s) in default aperture 64 0x00000040 All VDFS catalogues
1 15 Source in poor flat field region 32768 0x00008000 All but mosaics
2 16 Close to saturated 65536 0x00010000 All VDFS catalogues (though deeps excluded prior to DR8)
2 17 Photometric calibration probably subject to systematic error 131072 0x00020000 GPS only
2 19 Possible crosstalk artefact/contamination 524288 0x00080000 All but GPS
2 22 Lies within a dither offset of the stacked frame boundary 4194304 0x00400000 All but mosaics

In this way, the higher the error quality bit flag value, the more likely it is that the detection is spurious. The decimal threshold (column 4) gives the minimum value of the quality flag for a detection having the given condition (since other bits in the flag may be set also; the corresponding hexadecimal value, where each digit corresponds to 4 bits in the flag, can be easier to compute when writing SQL queries to test for a given condition). For example, to exclude all K band sources in the LAS having any error quality condition other than informational ones, include a predicate ... AND kppErrBits ≤ 255. See the SQL Cookbook and other online pages for further information.
j_2PsfMag lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Point source profile-fitted 2nd epoch J mag real 4 mag -0.9999995e9 PHOT_MAG
j_2PsfMagErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in point source profile-fitted 2nd epoch J mag real 4 mag -0.9999995e9 ERROR
j_2SeqNum lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA the running number of the 2nd epoch J detection int 4   -99999999 ID_NUMBER
j_2SeqNum lasSourceRemeasurement WSA the running number of the 2nd epoch J remeasurement int 4   -99999999 ID_NUMBER
j_2SerMag2D lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Extended source 2nd epoch J mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
j_2SerMag2DErr lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableLasPointSource WSA Error in extended source 2nd epoch J mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
j_2Xi lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Offset of 2nd epoch J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
j_2Xi lasSource WSA Offset of 2nd epoch J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
j_5sig_ba twomass_xsc 2MASS J minor/major axis ratio fit to the 5-sigma isophote. real 4     PHYS_AXIS-RATIO
j_5sig_phi twomass_xsc 2MASS J angle to 5-sigma major axis (E of N). smallint 2 degrees   ERROR
j_5surf twomass_xsc 2MASS J central surface brightness (r<=5). real 4 mag   PHOT_SB_GENERAL
j_ba twomass_xsc 2MASS J minor/major axis ratio fit to the 3-sigma isophote. real 4     PHYS_AXIS-RATIO
j_back twomass_xsc 2MASS J coadd median background. real 4     CODE_MISC
j_bisym_chi twomass_xsc 2MASS J bi-symmetric cross-correlation chi. real 4     FIT_PARAM_VALUE
j_bisym_rat twomass_xsc 2MASS J bi-symmetric flux ratio. real 4     PHOT_FLUX_RATIO
j_bndg_amp twomass_xsc 2MASS J banding maximum FT amplitude on this side of coadd. real 4 DN   FIT_PARAM_VALUE
j_bndg_per twomass_xsc 2MASS J banding Fourier Transf. period on this side of coadd. int 4 arcsec   FIT_PARAM_VALUE
j_chif_ellf twomass_xsc 2MASS J % chi-fraction for elliptical fit to 3-sig isophote. real 4     FIT_PARAM_VALUE
j_cmsig twomass_psc 2MASS Corrected photometric uncertainty for the default J-band magnitude. real 4 mag   SPECT_FLUX_VALUE
j_con_indx twomass_xsc 2MASS J concentration index r_75%/r_25%. real 4     PHYS_CONCENT_INDEX
j_d_area twomass_xsc 2MASS J 5-sigma to 3-sigma differential area. smallint 2     FIT_RESIDUAL
j_flg_10 twomass_xsc 2MASS J confusion flag for 10 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_15 twomass_xsc 2MASS J confusion flag for 15 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_20 twomass_xsc 2MASS J confusion flag for 20 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_25 twomass_xsc 2MASS J confusion flag for 25 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_30 twomass_xsc 2MASS J confusion flag for 30 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_40 twomass_xsc 2MASS J confusion flag for 40 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_5 twomass_xsc 2MASS J confusion flag for 5 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_50 twomass_xsc 2MASS J confusion flag for 50 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_60 twomass_xsc 2MASS J confusion flag for 60 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_7 twomass_sixx2_xsc 2MASS J confusion flag for 7 arcsec circular ap. mag smallint 2      
j_flg_7 twomass_xsc 2MASS J confusion flag for 7 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_70 twomass_xsc 2MASS J confusion flag for 70 arcsec circular ap. mag. smallint 2     CODE_MISC
j_flg_c twomass_xsc 2MASS J confusion flag for Kron circular mag. smallint 2     CODE_MISC
j_flg_e twomass_xsc 2MASS J confusion flag for Kron elliptical mag. smallint 2     CODE_MISC
j_flg_fc twomass_xsc 2MASS J confusion flag for fiducial Kron circ. mag. smallint 2     CODE_MISC
j_flg_fe twomass_xsc 2MASS J confusion flag for fiducial Kron ell. mag. smallint 2     CODE_MISC
j_flg_i20c twomass_xsc 2MASS J confusion flag for 20mag/sq." iso. circ. mag. smallint 2     CODE_MISC
j_flg_i20e twomass_xsc 2MASS J confusion flag for 20mag/sq." iso. ell. mag. smallint 2     CODE_MISC
j_flg_i21c twomass_xsc 2MASS J confusion flag for 21mag/sq." iso. circ. mag. smallint 2     CODE_MISC
j_flg_i21e twomass_xsc 2MASS J confusion flag for 21mag/sq." iso. ell. mag. smallint 2     CODE_MISC
j_flg_j21fc twomass_xsc 2MASS J confusion flag for 21mag/sq." iso. fid. circ. mag. smallint 2     CODE_MISC
j_flg_j21fe twomass_xsc 2MASS J confusion flag for 21mag/sq." iso. fid. ell. mag. smallint 2     CODE_MISC
j_flg_k20fc twomass_xsc 2MASS J confusion flag for 20mag/sq." iso. fid. circ. mag. smallint 2     CODE_MISC
j_flg_k20fe twomass_sixx2_xsc 2MASS J confusion flag for 20mag/sq.″ iso. fid. ell. mag smallint 2      
j_flg_k20fe twomass_xsc 2MASS J confusion flag for 20mag/sq." iso. fid. ell. mag. smallint 2     CODE_MISC
j_h twomass_sixx2_psc 2MASS The J-H color, computed from the J-band and H-band magnitudes (j_m and h_m, respectively) of the source. In cases where the first or second digit in rd_flg is equal to either "0", "4", "6", or "9", no color is computed because the photometry in one or both bands is of lower quality or the source is not detected. real 4      
j_k twomass_sixx2_psc 2MASS The J-Ks color, computed from the J-band and Ks-band magnitudes (j_m and k_m, respectively) of the source. In cases where the first or third digit in rd_flg is equal to either "0", "4", "6", or "9", no color is computed because the photometry in one or both bands is of lower quality or the source is not detected. real 4      
j_m twomass_psc 2MASS Default J-band magnitude real 4 mag   SPECT_FLUX_VALUE
j_m twomass_sixx2_psc 2MASS J selected "default" magnitude real 4 mag    
j_m_10 twomass_xsc 2MASS J 10 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_15 twomass_xsc 2MASS J 15 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_20 twomass_xsc 2MASS J 20 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_25 twomass_xsc 2MASS J 25 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_2mass allwise_sc2 WISE 2MASS J-band magnitude or magnitude upper limit of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC J-band magnitude entry is "null". float 8 mag    
j_m_30 twomass_xsc 2MASS J 30 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_40 twomass_xsc 2MASS J 40 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_5 twomass_xsc 2MASS J 5 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_50 twomass_xsc 2MASS J 50 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_60 twomass_xsc 2MASS J 60 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_7 twomass_sixx2_xsc 2MASS J 7 arcsec radius circular aperture magnitude real 4 mag    
j_m_7 twomass_xsc 2MASS J 7 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_70 twomass_xsc 2MASS J 70 arcsec radius circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_c twomass_xsc 2MASS J Kron circular aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_e twomass_xsc 2MASS J Kron elliptical aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_ext twomass_sixx2_xsc 2MASS J mag from fit extrapolation real 4 mag    
j_m_ext twomass_xsc 2MASS J mag from fit extrapolation. real 4 mag   SPECT_FLUX_VALUE
j_m_fc twomass_xsc 2MASS J fiducial Kron circular magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_fe twomass_xsc 2MASS J fiducial Kron ell. mag aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_i20c twomass_xsc 2MASS J 20mag/sq." isophotal circular ap. magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_i20e twomass_xsc 2MASS J 20mag/sq." isophotal elliptical ap. magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_i21c twomass_xsc 2MASS J 21mag/sq." isophotal circular ap. magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_i21e twomass_xsc 2MASS J 21mag/sq." isophotal elliptical ap. magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_j21fc twomass_xsc 2MASS J 21mag/sq." isophotal fiducial circ. ap. mag. real 4 mag   SPECT_FLUX_VALUE
j_m_j21fe twomass_xsc 2MASS J 21mag/sq." isophotal fiducial ell. ap. magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_k20fc twomass_xsc 2MASS J 20mag/sq." isophotal fiducial circ. ap. mag. real 4 mag   SPECT_FLUX_VALUE
j_m_k20fe twomass_sixx2_xsc 2MASS J 20mag/sq.″ isophotal fiducial ell. ap. magnitude real 4 mag    
j_m_k20fe twomass_xsc 2MASS J 20mag/sq." isophotal fiducial ell. ap. magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_stdap twomass_psc 2MASS J-band "standard" aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_m_sys twomass_xsc 2MASS J system photometry magnitude. real 4 mag   SPECT_FLUX_VALUE
j_mnsurfb_eff twomass_xsc 2MASS J mean surface brightness at the half-light radius. real 4 mag   PHOT_SB_GENERAL
j_msig twomass_sixx2_psc 2MASS J "default" mag uncertainty real 4 mag    
j_msig_10 twomass_xsc 2MASS J 1-sigma uncertainty in 10 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_15 twomass_xsc 2MASS J 1-sigma uncertainty in 15 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_20 twomass_xsc 2MASS J 1-sigma uncertainty in 20 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_25 twomass_xsc 2MASS J 1-sigma uncertainty in 25 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_2mass allwise_sc2 WISE 2MASS J-band corrected photometric uncertainty of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC J-band uncertainty entry is "null". float 8 mag    
j_msig_30 twomass_xsc 2MASS J 1-sigma uncertainty in 30 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_40 twomass_xsc 2MASS J 1-sigma uncertainty in 40 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_5 twomass_xsc 2MASS J 1-sigma uncertainty in 5 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_50 twomass_xsc 2MASS J 1-sigma uncertainty in 50 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_60 twomass_xsc 2MASS J 1-sigma uncertainty in 60 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_7 twomass_sixx2_xsc 2MASS J 1-sigma uncertainty in 7 arcsec circular ap. mag real 4 mag    
j_msig_7 twomass_xsc 2MASS J 1-sigma uncertainty in 7 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_70 twomass_xsc 2MASS J 1-sigma uncertainty in 70 arcsec circular ap. mag. real 4 mag   ERROR
j_msig_c twomass_xsc 2MASS J 1-sigma uncertainty in Kron circular mag. real 4 mag   ERROR
j_msig_e twomass_xsc 2MASS J 1-sigma uncertainty in Kron elliptical mag. real 4 mag   ERROR
j_msig_ext twomass_sixx2_xsc 2MASS J 1-sigma uncertainty in mag from fit extrapolation real 4 mag    
j_msig_ext twomass_xsc 2MASS J 1-sigma uncertainty in mag from fit extrapolation. real 4 mag   ERROR
j_msig_fc twomass_xsc 2MASS J 1-sigma uncertainty in fiducial Kron circ. mag. real 4 mag   ERROR
j_msig_fe twomass_xsc 2MASS J 1-sigma uncertainty in fiducial Kron ell. mag. real 4 mag   ERROR
j_msig_i20c twomass_xsc 2MASS J 1-sigma uncertainty in 20mag/sq." iso. circ. mag. real 4 mag   ERROR
j_msig_i20e twomass_xsc 2MASS J 1-sigma uncertainty in 20mag/sq." iso. ell. mag. real 4 mag   ERROR
j_msig_i21c twomass_xsc 2MASS J 1-sigma uncertainty in 21mag/sq." iso. circ. mag. real 4 mag   ERROR
j_msig_i21e twomass_xsc 2MASS J 1-sigma uncertainty in 21mag/sq." iso. ell. mag. real 4 mag   ERROR
j_msig_j21fc twomass_xsc 2MASS J 1-sigma uncertainty in 21mag/sq." iso.fid.circ.mag. real 4 mag   ERROR
j_msig_j21fe twomass_xsc 2MASS J 1-sigma uncertainty in 21mag/sq." iso.fid.ell.mag. real 4 mag   ERROR
j_msig_k20fc twomass_xsc 2MASS J 1-sigma uncertainty in 20mag/sq." iso.fid.circ. mag. real 4 mag   ERROR
j_msig_k20fe twomass_xsc 2MASS J 1-sigma uncertainty in 20mag/sq." iso.fid.ell.mag. real 4 mag   ERROR
j_msig_stdap twomass_psc 2MASS Uncertainty in the J-band standard aperture magnitude. real 4 mag   SPECT_FLUX_VALUE
j_msig_sys twomass_xsc 2MASS J 1-sigma uncertainty in system photometry mag. real 4 mag   ERROR
j_msigcom twomass_psc 2MASS Combined, or total photometric uncertainty for the default J-band magnitude. real 4 mag   SPECT_FLUX_VALUE
j_msigcom twomass_sixx2_psc 2MASS combined (total) J band photometric uncertainty real 4 mag    
j_msnr10 twomass_scn 2MASS The estimated J-band magnitude at which SNR=10 is achieved for this scan. real 4 mag   SPECT_FLUX_VALUE
j_msnr10 twomass_sixx2_scn 2MASS J mag at which SNR=10 is achieved, from j_psp and j_zp_ap real 4 mag    
j_n_snr10 twomass_scn 2MASS Number of point sources at J-band with SNR>10 (instrumental mag <=15.8) int 4     NUMBER
j_n_snr10 twomass_sixx2_scn 2MASS number of J point sources with SNR>10 (instrumental m<=15.8) int 4      
j_pchi twomass_xsc 2MASS J chi^2 of fit to rad. profile (LCSB: alpha scale len). real 4     FIT_PARAM_VALUE
j_peak twomass_xsc 2MASS J peak pixel brightness. real 4 mag   PHOT_SB_GENERAL
j_perc_darea twomass_xsc 2MASS J 5-sigma to 3-sigma percent area change. smallint 2     FIT_PARAM
j_phi twomass_xsc 2MASS J angle to 3-sigma major axis (E of N). smallint 2 degrees   POS_POS-ANG
j_psfchi twomass_psc 2MASS Reduced chi-squared goodness-of-fit value for the J-band profile-fit photometry made on the 1.3 s "Read_2" exposures. real 4     FIT_PARAM_VALUE
j_psp twomass_scn 2MASS J-band photometric sensitivity paramater (PSP). real 4     INST_SENSITIVITY
j_psp twomass_sixx2_scn 2MASS J photometric sensitivity param: j_shape_avg*(j_fbg_avg^.29) real 4      
j_pts_noise twomass_scn 2MASS Base-10 logarithm of the mode of the noise distribution for all point source detections in the scan, where the noise is estimated from the measured J-band photometric errors and is expressed in units of mJy. real 4     INST_NOISE
j_pts_noise twomass_sixx2_scn 2MASS log10 of J band modal point src noise estimate real 4 logmJy    
j_r_c twomass_xsc 2MASS J Kron circular aperture radius. real 4 arcsec   EXTENSION_RAD
j_r_e twomass_xsc 2MASS J Kron elliptical aperture semi-major axis. real 4 arcsec   EXTENSION_RAD
j_r_eff twomass_xsc 2MASS J half-light (integrated half-flux point) radius. real 4 arcsec   EXTENSION_RAD
j_r_i20c twomass_xsc 2MASS J 20mag/sq." isophotal circular aperture radius. real 4 arcsec   EXTENSION_RAD
j_r_i20e twomass_xsc 2MASS J 20mag/sq." isophotal elliptical ap. semi-major axis. real 4 arcsec   EXTENSION_RAD
j_r_i21c twomass_xsc 2MASS J 21mag/sq." isophotal circular aperture radius. real 4 arcsec   EXTENSION_RAD
j_r_i21e twomass_xsc 2MASS J 21mag/sq." isophotal elliptical ap. semi-major axis. real 4 arcsec   EXTENSION_RAD
j_resid_ann twomass_xsc 2MASS J residual annulus background median. real 4 DN   CODE_MISC
j_sc_1mm twomass_xsc 2MASS J 1st moment (score) (LCSB: super blk 2,4,8 SNR). real 4     CODE_MISC
j_sc_2mm twomass_xsc 2MASS J 2nd moment (score) (LCSB: SNRMAX - super SNR max). real 4     CODE_MISC
j_sc_msh twomass_xsc 2MASS J median shape score. real 4     CODE_MISC
j_sc_mxdn twomass_xsc 2MASS J mxdn (score) (LCSB: BSNR - block/smoothed SNR). real 4     CODE_MISC
j_sc_r1 twomass_xsc 2MASS J r1 (score). real 4     CODE_MISC
j_sc_r23 twomass_xsc 2MASS J r23 (score) (LCSB: TSNR - integrated SNR for r=15). real 4     CODE_MISC
j_sc_sh twomass_xsc 2MASS J shape (score). real 4     CODE_MISC
j_sc_vint twomass_xsc 2MASS J vint (score). real 4     CODE_MISC
j_sc_wsh twomass_xsc 2MASS J wsh (score) (LCSB: PSNR - peak raw SNR). real 4     CODE_MISC
j_seetrack twomass_xsc 2MASS J band seetracking score. real 4     CODE_MISC
j_sh0 twomass_xsc 2MASS J ridge shape (LCSB: BSNR limit). real 4     FIT_PARAM
j_shape_avg twomass_scn 2MASS J-band average seeing shape for scan. real 4     INST_SEEING
j_shape_avg twomass_sixx2_scn 2MASS J band average seeing shape for scan real 4      
j_shape_rms twomass_scn 2MASS RMS-error of J-band average seeing shape. real 4     INST_SEEING
j_shape_rms twomass_sixx2_scn 2MASS rms of J band avg seeing shape for scan real 4      
j_sig_sh0 twomass_xsc 2MASS J ridge shape sigma (LCSB: B2SNR limit). real 4     FIT_PARAM
j_snr twomass_psc 2MASS J-band "scan" signal-to-noise ratio. real 4 mag   INST_NOISE
j_snr twomass_sixx2_psc 2MASS J band "scan" signal-to-noise ratio real 4      
j_subst2 twomass_xsc 2MASS J residual background #2 (score). real 4     CODE_MISC
j_zp_ap twomass_scn 2MASS Photometric zero-point for J-band aperture photometry. real 4 mag   PHOT_ZP
j_zp_ap twomass_sixx2_scn 2MASS J band ap. calibration photometric zero-point for scan real 4 mag    
jAperMag1 calSynopticSource WSACalib Extended source J aperture corrected mag (0.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag1 gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource WSA Extended source J aperture corrected mag (1.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag1Err calSynopticSource WSACalib Error in extended source J mag (0.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag1Err gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource WSA Error in extended source J mag (1.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag2 calSynopticSource WSACalib Extended source J aperture corrected mag (1.4 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag2Err calSynopticSource WSACalib Error in extended source J mag (1.4 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag3 calSource WSACalib Default point/extended source J aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator		 real 4 mag -0.9999995e9 PHOT_MAG
jAperMag3 calSynopticSource WSACalib Default point/extended source J aperture corrected mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag3 dxsJKsource, gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource WSA Default point/extended source J aperture corrected mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag3 dxsSource, gcsSource, gpsSource WSA Default point/extended source J aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator		 real 4 mag -0.9999995e9 PHOT_MAG
jAperMag3 reliableUdsSource WSA Default point/extended source J mag, no aperture correction applied real 4 mag -0.9999995e9 PHOT_MAG
jAperMag3 udsSource WSA Default point/extended source J mag, no aperture correction applied
If in doubt use this flux estimator		 real 4 mag -0.9999995e9 PHOT_MAG
jAperMag3 uhsSource, uhsSourceAll WSAUHS Default point source J aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator		 real 4 mag -0.9999995e9 PHOT_MAG
jAperMag3Err calSource, calSynopticSource WSACalib Error in default point/extended source J mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag3Err dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA Error in default point/extended source J mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag3Err uhsSource, uhsSourceAll WSAUHS Error in default point source J mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag4 calSource, calSynopticSource WSACalib Extended source J aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag4 dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource WSA Extended source J aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag4 reliableUdsSource, udsSource WSA Extended source J mag, no aperture correction applied real 4 mag -0.9999995e9 PHOT_MAG
jAperMag4 uhsSource, uhsSourceAll WSAUHS Point source J aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag4Err calSource, calSynopticSource WSACalib Error in extended source J mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag4Err dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA Error in extended source J mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag4Err uhsSource, uhsSourceAll WSAUHS Error in point source J mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag5 calSynopticSource WSACalib Extended source J aperture corrected mag (4.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag5Err calSynopticSource WSACalib Error in extended source J mag (4.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag6 calSource WSACalib Extended source J aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag6 dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource WSA Extended source J aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag6 reliableUdsSource, udsSource WSA Extended source J mag, no aperture correction applied real 4 mag -0.9999995e9 PHOT_MAG
jAperMag6 uhsSource, uhsSourceAll WSAUHS Point source J aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
jAperMag6Err calSource WSACalib Error in extended source J mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag6Err dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource, reliableUdsSource, udsSource WSA Error in extended source J mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jAperMag6Err uhsSource, uhsSourceAll WSAUHS Error in point source J mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
jaStratAst calVarFrameSetInfo WSACalib Strateva parameter, a, in fit to astrometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jaStratAst dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Strateva parameter, a, in fit to astrometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jaStratPht calVarFrameSetInfo WSACalib Strateva parameter, a, in fit to photometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jaStratPht dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Strateva parameter, a, in fit to photometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jbestAper calVariability WSACalib Best aperture (1-6) for photometric statistics in the J band int 4   -9999  
Aperture magnitude (1-6) which gives the lowest RMS for the object. All apertures have the appropriate aperture correction. This can give better values in crowded regions than aperMag3 (see Irwin et al. 2007, MNRAS, 375, 1449)
jbestAper dxsVariability, udsVariability WSA Best aperture (1-6) for photometric statistics in the J band int 4   -9999  
Aperture magnitude (1-6) which gives the lowest RMS for the object. All apertures have the appropriate aperture correction. This can give better values in crowded regions than aperMag3 (see Irwin et al. 2007, MNRAS, 375, 1449)
jbStratAst calVarFrameSetInfo WSACalib Strateva parameter, b, in fit to astrometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jbStratAst dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Strateva parameter, b, in fit to astrometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jbStratPht calVarFrameSetInfo WSACalib Strateva parameter, b, in fit to photometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jbStratPht dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Strateva parameter, b, in fit to photometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jchiSqAst calVarFrameSetInfo WSACalib Goodness of fit of Strateva function to astrometric data in J band real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jchiSqAst dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Goodness of fit of Strateva function to astrometric data in J band real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jchiSqpd calVariability WSACalib Chi square (per degree of freedom) fit to data (mean and expected rms) real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jchiSqpd dxsVariability, udsVariability WSA Chi square (per degree of freedom) fit to data (mean and expected rms) real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jchiSqPht calVarFrameSetInfo WSACalib Goodness of fit of Strateva function to photometric data in J band real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jchiSqPht dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Goodness of fit of Strateva function to photometric data in J band real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jClass calSource, calSynopticSource WSACalib discrete image classification flag in J smallint 2   -9999 CLASS_MISC
jClass dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA discrete image classification flag in J smallint 2   -9999 CLASS_MISC
jClass uhsSource, uhsSourceAll WSAUHS discrete image classification flag in J smallint 2   -9999 CLASS_MISC
jClassStat calSource, calSynopticSource WSACalib N(0,1) stellarness-of-profile statistic in J real 4   -0.9999995e9 STAT_PROP
jClassStat dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource WSA N(0,1) stellarness-of-profile statistic in J real 4   -0.9999995e9 STAT_PROP
jClassStat gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA S-Extractor classification statistic in J real 4   -0.9999995e9 STAT_PROP
jClassStat uhsSource, uhsSourceAll WSAUHS N(0,1) stellarness-of-profile statistic in J real 4   -0.9999995e9 STAT_PROP
jcStratAst calVarFrameSetInfo WSACalib Strateva parameter, c, in fit to astrometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jcStratAst dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Strateva parameter, c, in fit to astrometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jcStratPht calVarFrameSetInfo WSACalib Strateva parameter, c, in fit to photometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jcStratPht dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Strateva parameter, c, in fit to photometric rms vs magnitude in J band, see Sesar et al. 2007. real 4   -0.9999995e9  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jdate twomass_psc 2MASS The Julian Date of the source measurement accurate to +-30 seconds. float 8 Julian days   TIME_DATE
jdate twomass_scn 2MASS Julian Date at beginning of scan. float 8 Julian days   TIME_DATE
jdate twomass_sixx2_psc 2MASS julian date of source measurement to +/- 30 sec float 8 jdate    
jdate twomass_sixx2_scn 2MASS Julian date beginning UT of scan data float 8 jdate    
jdate twomass_xsc 2MASS Julian date of the source measurement accurate to +-3 minutes. float 8 Julian days   TIME_DATE
jDeblend calSource WSACalib placeholder flag indicating parent/child relation in J int 4   -99999999 CODE_MISC
This CASU pipeline processing source extraction flag is a placeholder only, and is always set to zero in all passbands in the merged source lists. If you need to know when a particular image detection is a component of a deblend or not, test bit 4 of attribute ppErrBits (see corresponding glossary entry) which is set by WFAU's post-processing software based on testing the areal profiles aprof2-8 (these are set by CASU to -1 for deblended components, or positive values for non-deblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables.
jDeblend calSynopticSource WSACalib placeholder flag indicating parent/child relation in J int 4   -99999999 CODE_MISC
jDeblend dxsJKsource, gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA placeholder flag indicating parent/child relation in J int 4   -99999999 CODE_MISC
jDeblend dxsSource, gcsSource WSA placeholder flag indicating parent/child relation in J int 4   -99999999 CODE_MISC
This CASU pipeline processing source extraction flag is a placeholder only, and is always set to zero in all passbands in the merged source lists. If you need to know when a particular image detection is a component of a deblend or not, test bit 4 of attribute ppErrBits (see corresponding glossary entry) which is set by WFAU's post-processing software based on testing the areal profiles aprof2-8 (these are set by CASU to -1 for deblended components, or positive values for non-deblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables.
jDeblend uhsSource, uhsSourceAll WSAUHS placeholder flag indicating parent/child relation in J int 4   -99999999 CODE_MISC
This CASU pipeline processing source extraction flag is a placeholder only, and is always set to zero in all passbands in the merged source lists. If you need to know when a particular image detection is a component of a deblend or not, test bit 4 of attribute ppErrBits (see corresponding glossary entry) which is set by WFAU's post-processing software based on testing the areal profiles aprof2-8 (these are set by CASU to -1 for deblended components, or positive values for non-deblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables.
jEll calSource, calSynopticSource WSACalib 1-b/a, where a/b=semi-major/minor axes in J real 4   -0.9999995e9 PHYS_ELLIPTICITY
jEll dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA 1-b/a, where a/b=semi-major/minor axes in J real 4   -0.9999995e9 PHYS_ELLIPTICITY
jEll uhsSource, uhsSourceAll WSAUHS 1-b/a, where a/b=semi-major/minor axes in J real 4   -0.9999995e9 PHYS_ELLIPTICITY
jeNum calMergeLog, calSynopticMergeLog WSACalib the extension number of this J frame tinyint 1     NUMBER
jeNum dxsJKmergeLog, gpsJHKmergeLog WSA the extension number of this frame tinyint 1     NUMBER
jeNum dxsMergeLog, gcsMergeLog, gcsZYJHKmergeLog, gpsMergeLog, udsMergeLog WSA the extension number of this J frame tinyint 1     NUMBER
jeNum uhsMergeLog WSAUHS the extension number of this J frame tinyint 1     NUMBER
jErrBits calSource, calSynopticSource WSACalib processing warning/error bitwise flags in J int 4   -99999999 CODE_MISC
Apparently not actually an error bit flag, but a count of the number of zero confidence pixels in the default (2 arcsec diameter) aperture.
jErrBits dxsJKsource, gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource WSA processing warning/error bitwise flags in J int 4   -99999999 CODE_MISC
jErrBits dxsSource, gcsSource WSA processing warning/error bitwise flags in J int 4   -99999999 CODE_MISC
Apparently not actually an error bit flag, but a count of the number of zero confidence pixels in the default (2 arcsec diameter) aperture.
jErrBits gpsSource, udsSource WSA processing warning/error bitwise flags in J int 4   -99999999 CODE_MISC
This uses the FLAGS attribute in SE. The individual bit flags that this can be decomposed into are as follows:
Bit FlagMeaning
1The object has neighbours, bright enough and close enough to significantly bias the MAG_AUTO photometry or bad pixels (more than 10% of photometry affected).
2The object was originally blended with another
4At least one pixel is saturated (or very close to)
8The object is truncated (too close to an image boundary)
16Object's aperture data are incomplete or corrupted
32Object's isophotal data are imcomplete or corrupted. This is an old flag inherited from SE v1.0, and is kept for compatability reasons. It doesn't have any consequence for the extracted parameters.
64Memory overflow occurred during deblending
128Memory overflow occurred during extraction

jErrBits uhsSource, uhsSourceAll WSAUHS processing warning/error bitwise flags in J int 4   -99999999 CODE_MISC
Apparently not actually an error bit flag, but a count of the number of zero confidence pixels in the default (2 arcsec diameter) aperture.
jEta calSource, calSynopticSource WSACalib Offset of J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
jEta dxsJKsource, gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource WSA Offset of J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
jEta dxsSource, gcsSource, gpsSource, udsSource WSA Offset of J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
jEta uhsSource, uhsSourceAll WSAUHS Offset of J detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
jexpML calVarFrameSetInfo WSACalib Expected magnitude limit of frameSet in this in J band. real 4   -0.9999995e9  
The expected magnitude limit of an intermediate stack, based on the total exposure time. expML=Filter.oneSecML+1.25*log10(totalExpTime). Since different intermediate stacks can have different exposure times, the totalExpTime is the minimum, as long as the number of stacks with this minimum make up 10% of the total. This is a more conservative treatment than just taking the mean or median total exposure time.
jexpML dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Expected magnitude limit of frameSet in this in J band. real 4   -0.9999995e9  
The expected magnitude limit of an intermediate stack, based on the total exposure time. expML=Filter.oneSecML+1.25*log10(totalExpTime). Since different intermediate stacks can have different exposure times, the totalExpTime is the minimum, as long as the number of stacks with this minimum make up 10% of the total. This is a more conservative treatment than just taking the mean or median total exposure time.
jExpRms calVariability WSACalib Rms calculated from polynomial fit to modal RMS as a function of magnitude in J band real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jExpRms dxsVariability, udsVariability WSA Rms calculated from polynomial fit to modal RMS as a function of magnitude in J band real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jGausig calSource, calSynopticSource WSACalib RMS of axes of ellipse fit in J real 4 pixels -0.9999995e9 MORPH_PARAM
jGausig dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA RMS of axes of ellipse fit in J real 4 pixels -0.9999995e9 MORPH_PARAM
jGausig uhsSource, uhsSourceAll WSAUHS RMS of axes of ellipse fit in J real 4 pixels -0.9999995e9 MORPH_PARAM
jHallMag calSource WSACalib Total point source J mag real 4 mag -0.9999995e9 PHOT_MAG
jHallMag dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource WSA Total point source J mag real 4 mag -0.9999995e9 PHOT_MAG
jHallMag reliableUdsSource, udsSource WSA Not available in SE output real 4 mag -0.9999995e9 PHOT_MAG
jHallMag uhsSource, uhsSourceAll WSAUHS Total point source J mag real 4 mag -0.9999995e9 PHOT_MAG
jHallMagErr calSource WSACalib Error in total point source J mag real 4 mag -0.9999995e9 ERROR
jHallMagErr dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource WSA Error in total point source J mag real 4 mag -0.9999995e9 ERROR
jHallMagErr reliableUdsSource, udsSource WSA Not available in SE output real 4 mag -0.9999995e9 ERROR
jHallMagErr uhsSource, uhsSourceAll WSAUHS Error in total point source J mag real 4 mag -0.9999995e9 ERROR
jhiWS calVariability WSACalib Welch-Stetson statistic between J and H. This assumes colour does not vary much and helps remove variation due to a few poor detections real 4   -0.9999995e9  
The Welch-Stetson statistic is a measure of the correlation of the variability between two bands. We use the calculation in Welch D.L. and Stetson P.B. 1993, AJ, 105, 5, which is also used in Sesar et al. 2007, AJ, 134, 2236. We use the aperMag3 magnitude when comparing between bands.
jIntRms calVariability WSACalib Intrinsic rms in J-band real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jIntRms dxsVariability, udsVariability WSA Intrinsic rms in J-band real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jisDefAst calVarFrameSetInfo WSACalib Use a default model for the astrometric noise in J band. tinyint 1   0  
jisDefAst dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Use a default model for the astrometric noise in J band. tinyint 1   0  
jisDefPht calVarFrameSetInfo WSACalib Use a default model for the photometric noise in J band. tinyint 1   0  
jisDefPht dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Use a default model for the photometric noise in J band. tinyint 1   0  
jitterID Multiframe WSA Serial number in this telescope jitter pattern {image primary HDU keyword: JITTER_I} smallint 2   -9999 meta.id
jitterID Multiframe WSACalib Serial number in this telescope jitter pattern {image primary HDU keyword: JITTER_I} smallint 2   -9999 meta.id
jitterID Multiframe WSATransit Serial number in this telescope jitter pattern {image primary HDU keyword: JITTER_I} smallint 2   -9999 meta.id
jitterID Multiframe WSAUHS Serial number in this telescope jitter pattern {image primary HDU keyword: JITTER_I} smallint 2   -9999 meta.id
jitterX Multiframe WSA X (RA) offset in tel jitter pattern {image primary HDU keyword: JITTER_X} real 4 arcsec -0.9999995e9 pos.eq.ra;arith.diff
jitterX Multiframe WSACalib X (RA) offset in tel jitter pattern {image primary HDU keyword: JITTER_X} real 4 arcsec -0.9999995e9 pos.eq.ra;arith.diff
jitterX Multiframe WSATransit X (RA) offset in tel jitter pattern {image primary HDU keyword: JITTER_X} real 4 arcsec -0.9999995e9 pos.eq.ra;arith.diff
jitterX Multiframe WSAUHS X (RA) offset in tel jitter pattern {image primary HDU keyword: JITTER_X} real 4 arcsec -0.9999995e9 pos.eq.ra;arith.diff
jitterY Multiframe WSA Y (Dec) offset in tel jitter pattern {image primary HDU keyword: JITTER_Y} real 4 arcsec -0.9999995e9 pos.eq.dec;arith.diff
jitterY Multiframe WSACalib Y (Dec) offset in tel jitter pattern {image primary HDU keyword: JITTER_Y} real 4 arcsec -0.9999995e9 pos.eq.dec;arith.diff
jitterY Multiframe WSATransit Y (Dec) offset in tel jitter pattern {image primary HDU keyword: JITTER_Y} real 4 arcsec -0.9999995e9 pos.eq.dec;arith.diff
jitterY Multiframe WSAUHS Y (Dec) offset in tel jitter pattern {image primary HDU keyword: JITTER_Y} real 4 arcsec -0.9999995e9 pos.eq.dec;arith.diff
jMag gcsSourceRemeasurement, gpsSourceRemeasurement WSA J mag (as appropriate for this merged source) real 4 mag -0.9999995e9 PHOT_MAG
jMag ukirtFSstars WSA J band total magnitude on the MKO(UFTI) system real 4 mag   PHOT_INT-MAG
jMag ukirtFSstars WSACalib J band total magnitude on the MKO(UFTI) system real 4 mag   PHOT_INT-MAG
jMag ukirtFSstars WSAUHS J band total magnitude on the MKO(UFTI) system real 4 mag   PHOT_INT-MAG
jMagErr gcsSourceRemeasurement, gpsSourceRemeasurement WSA Error in J mag real 4 mag -0.9999995e9 ERROR
jMagErr ukirtFSstars WSA J band magnitude error real 4 mag   ERROR
jMagErr ukirtFSstars WSACalib J band magnitude error real 4 mag   ERROR
jMagErr ukirtFSstars WSAUHS J band magnitude error real 4 mag   ERROR
jMagMAD calVariability WSACalib Median Absolute Deviation of J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jMagMAD dxsVariability, udsVariability WSA Median Absolute Deviation of J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jMagRms calVariability WSACalib rms of J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jMagRms dxsVariability, udsVariability WSA rms of J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jmaxCadence calVariability WSACalib maximum gap between observations real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jmaxCadence dxsVariability, udsVariability WSA maximum gap between observations real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jMaxMag calVariability WSACalib Maximum magnitude in J band, of good detections real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jMaxMag dxsVariability, udsVariability WSA Maximum magnitude in J band, of good detections real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jmeanMag calVariability WSACalib Mean J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jmeanMag dxsVariability, udsVariability WSA Mean J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jmedCadence calVariability WSACalib median gap between observations real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jmedCadence dxsVariability, udsVariability WSA median gap between observations real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jmedianMag calVariability WSACalib Median J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jmedianMag dxsVariability, udsVariability WSA Median J magnitude real 4 mag -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jmfID calMergeLog, calSynopticMergeLog WSACalib the UID of the relevant J multiframe bigint 8     ID_FRAME
jmfID dxsJKmergeLog, gpsJHKmergeLog WSA the UID of the relevant multiframe bigint 8     ID_FRAME
jmfID dxsMergeLog, gcsMergeLog, gcsZYJHKmergeLog, gpsMergeLog, udsMergeLog WSA the UID of the relevant J multiframe bigint 8     ID_FRAME
jmfID uhsMergeLog WSAUHS the UID of the relevant J multiframe bigint 8     ID_FRAME
jmh gcsSourceRemeasurement, gpsSourceRemeasurement, lasSourceRemeasurement WSA Default colour J-H (using appropriate mags) real 4 mag   PHOT_COLOR
jmhErr gcsSourceRemeasurement, gpsSourceRemeasurement, lasSourceRemeasurement WSA Error on colour J-H real 4 mag   ERROR
jmhExt calSource WSACalib Extended source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmhExt dxsJKsource, gcsPointSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource, reliableUdsSource WSA Extended source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
jmhExt dxsSource, gcsSource, udsSource WSA Extended source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmhExtErr calSource WSACalib Error on extended source colour J-H real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmhExtErr dxsJKsource, gcsPointSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource, reliableUdsSource WSA Error on extended source colour J-H real 4 mag -0.9999995e9 ERROR
jmhExtErr dxsSource, gcsSource, udsSource WSA Error on extended source colour J-H real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmhPnt calSource, calSynopticSource WSACalib Point source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmhPnt dxsJKsource, gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource WSA Point source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
jmhPnt dxsSource, gcsSource, gpsSource, udsSource WSA Point source colour J-H (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmhPntErr calSource, calSynopticSource WSACalib Error on point source colour J-H real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmhPntErr dxsJKsource, gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource WSA Error on point source colour J-H real 4 mag -0.9999995e9 ERROR
jmhPntErr dxsSource, gcsSource, gpsSource, udsSource WSA Error on point source colour J-H real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jminCadence calVariability WSACalib minimum gap between observations real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jminCadence dxsVariability, udsVariability WSA minimum gap between observations real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jMinMag calVariability WSACalib Minimum magnitude in J band, of good detections real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jMinMag dxsVariability, udsVariability WSA Minimum magnitude in J band, of good detections real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jmkExt dxsJKsource, reliableDxsSource WSA Extended source colour J-K (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
jmkExt dxsSource WSA Extended source colour J-K (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmkExtErr dxsJKsource, reliableDxsSource WSA Error on extended source colour J-K real 4 mag -0.9999995e9 ERROR
jmkExtErr dxsSource WSA Error on extended source colour J-K real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmkPnt dxsJKsource, reliableDxsSource WSA Point source colour J-K (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
jmkPnt dxsSource WSA Point source colour J-K (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jmkPntErr dxsJKsource, reliableDxsSource WSA Error on point source colour J-K real 4 mag -0.9999995e9 ERROR
jmkPntErr dxsSource WSA Error on point source colour J-K real 4 mag -0.9999995e9 ERROR
Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
jndof calVariability WSACalib Number of degrees of freedom for chisquare smallint 2   -9999  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jndof dxsVariability, udsVariability WSA Number of degrees of freedom for chisquare smallint 2   -9999  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jnDofAst calVarFrameSetInfo WSACalib Number of degrees of freedom of astrometric fit in J band. smallint 2   -9999  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jnDofAst dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Number of degrees of freedom of astrometric fit in J band. smallint 2   -9999  
The best fit solution to the expected RMS position around the mean for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated.
jnDofPht calVarFrameSetInfo WSACalib Number of degrees of freedom of photometric fit in J band. smallint 2   -9999  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jnDofPht dxsVarFrameSetInfo, udsVarFrameSetInfo WSA Number of degrees of freedom of photometric fit in J band. smallint 2   -9999  
The best fit solution to the expected RMS brightness (in magnitudes) for all objects in the frameset. Objects were binned in ranges of magnitude and the median RMS (after clipping out variable objects using the median-absolute deviation) was calculated. The Strateva function $\zeta(m)>=a+b\,10^{0.4m}+c\,10^{0.8m}$ was fit, where $\zeta(m)$ is the expected RMS as a function of magnitude. The chi-squared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236.
jnFlaggedObs calVariability WSACalib Number of detections in J band flagged as potentially spurious by calDetection.ppErrBits int 4   0  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jnFlaggedObs dxsVariability WSA Number of detections in J band flagged as potentially spurious by dxsDetection.ppErrBits int 4   0  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jnFlaggedObs udsVariability WSA Number of detections in J band flagged as potentially spurious by udsDetection.ppErrBits int 4   0  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jnGoodObs calVariability WSACalib Number of good detections in J band int 4   0  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jnGoodObs dxsVariability, udsVariability WSA Number of good detections in J band int 4   0  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jNgt3sig calVariability WSACalib Number of good detections in J-band that are more than 3 sigma deviations smallint 2   -9999  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jNgt3sig dxsVariability, udsVariability WSA Number of good detections in J-band that are more than 3 sigma deviations smallint 2   -9999  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jnMissingObs calVariability WSACalib Number of J band frames that this object should have been detected on and was not int 4   0  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jnMissingObs dxsVariability, udsVariability WSA Number of J band frames that this object should have been detected on and was not int 4   0  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jObjID gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource WSA DEPRECATED (do not use) bigint 8   -99999999 ID_NUMBER
jObjID gcsSource, gcsSourceRemeasurement, gpsSource, gpsSourceRemeasurement WSA DEPRECATED (do not use) bigint 8   -99999999 ID_NUMBER
This attribute is included in source tables for historical reasons, but it's use is not recommended unless you really know what you are doing. In general, if you need to look up detection table attributes for a source in a given passband that are not in the source table, you should make an SQL join between source, mergelog and detection using the primary key attribute frameSetID and combination multiframeID, extNum, seqNum to associate related rows between the three tables. See the Q&A example SQL for more information.
joinCriterion RequiredNeighbours WSA the join criterion (search radius for matches) real 4 degrees   ??
joinCriterion RequiredNeighbours WSACalib the join criterion (search radius for matches) real 4 degrees   ??
joinCriterion RequiredNeighbours WSATransit the join criterion (search radius for matches) real 4 degrees   ??
joinCriterion RequiredNeighbours WSAUHS the join criterion (search radius for matches) real 4 degrees   ??
jPA calSource, calSynopticSource WSACalib ellipse fit celestial orientation in J real 4 Degrees -0.9999995e9 POS_POS-ANG
jPA dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA ellipse fit celestial orientation in J real 4 Degrees -0.9999995e9 POS_POS-ANG
jPA uhsSource, uhsSourceAll WSAUHS ellipse fit celestial orientation in J real 4 Degrees -0.9999995e9 POS_POS-ANG
jPetroMag calSource WSACalib Extended source J mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
jPetroMag dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource, reliableUdsSource, udsSource WSA Extended source J mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
jPetroMag uhsSource, uhsSourceAll WSAUHS Extended source J mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
jPetroMagErr calSource WSACalib Error in extended source J mag (Petrosian) real 4 mag -0.9999995e9 ERROR
jPetroMagErr dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource, reliableUdsSource, udsSource WSA Error in extended source J mag (Petrosian) real 4 mag -0.9999995e9 ERROR
jPetroMagErr uhsSource, uhsSourceAll WSAUHS Error in extended source J mag (Petrosian) real 4 mag -0.9999995e9 ERROR
jppErrBits calSource, calSynopticSource WSACalib additional WFAU post-processing error bits in J int 4   0 CODE_MISC
Post-processing error quality bit flags assigned (NB: from UKIDSS DR2 release onwards) in the WSA curation procedure for survey data. From least to most significant byte in the 4-byte integer attribute byte 0 (bits 0 to 7) corresponds to information on generally innocuous conditions that are nonetheless potentially significant as regards the integrity of that detection; byte 1 (bits 8 to 15) corresponds to warnings; byte 2 (bits 16 to 23) corresponds to important warnings; and finally byte 3 (bits 24 to 31) corresponds to severe warnings:
ByteBitDetection quality issue Threshold or bit mask Applies to
DecimalHexadecimal
0 4 Deblended 16 0x00000010 All VDFS catalogues
0 6 Bad pixel(s) in default aperture 64 0x00000040 All VDFS catalogues
1 15 Source in poor flat field region 32768 0x00008000 All but mosaics
2 16 Close to saturated 65536 0x00010000 All VDFS catalogues (though deeps excluded prior to DR8)
2 17 Photometric calibration probably subject to systematic error 131072 0x00020000 GPS only
2 19 Possible crosstalk artefact/contamination 524288 0x00080000 All but GPS
2 22 Lies within a dither offset of the stacked frame boundary 4194304 0x00400000 All but mosaics

In this way, the higher the error quality bit flag value, the more likely it is that the detection is spurious. The decimal threshold (column 4) gives the minimum value of the quality flag for a detection having the given condition (since other bits in the flag may be set also; the corresponding hexadecimal value, where each digit corresponds to 4 bits in the flag, can be easier to compute when writing SQL queries to test for a given condition). For example, to exclude all K band sources in the LAS having any error quality condition other than informational ones, include a predicate ... AND kppErrBits ≤ 255. See the SQL Cookbook and other online pages for further information.
jppErrBits dxsJKsource, gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA additional WFAU post-processing error bits in J int 4   0 CODE_MISC
jppErrBits dxsSource, gcsSource WSA additional WFAU post-processing error bits in J int 4   0 CODE_MISC
Post-processing error quality bit flags assigned (NB: from UKIDSS DR2 release onwards) in the WSA curation procedure for survey data. From least to most significant byte in the 4-byte integer attribute byte 0 (bits 0 to 7) corresponds to information on generally innocuous conditions that are nonetheless potentially significant as regards the integrity of that detection; byte 1 (bits 8 to 15) corresponds to warnings; byte 2 (bits 16 to 23) corresponds to important warnings; and finally byte 3 (bits 24 to 31) corresponds to severe warnings:
ByteBitDetection quality issue Threshold or bit mask Applies to
DecimalHexadecimal
0 4 Deblended 16 0x00000010 All VDFS catalogues
0 6 Bad pixel(s) in default aperture 64 0x00000040 All VDFS catalogues
1 15 Source in poor flat field region 32768 0x00008000 All but mosaics
2 16 Close to saturated 65536 0x00010000 All VDFS catalogues (though deeps excluded prior to DR8)
2 17 Photometric calibration probably subject to systematic error 131072 0x00020000 GPS only
2 19 Possible crosstalk artefact/contamination 524288 0x00080000 All but GPS
2 22 Lies within a dither offset of the stacked frame boundary 4194304 0x00400000 All but mosaics

In this way, the higher the error quality bit flag value, the more likely it is that the detection is spurious. The decimal threshold (column 4) gives the minimum value of the quality flag for a detection having the given condition (since other bits in the flag may be set also; the corresponding hexadecimal value, where each digit corresponds to 4 bits in the flag, can be easier to compute when writing SQL queries to test for a given condition). For example, to exclude all K band sources in the LAS having any error quality condition other than informational ones, include a predicate ... AND kppErrBits ≤ 255. See the SQL Cookbook and other online pages for further information.
jppErrBits uhsSource, uhsSourceAll WSAUHS additional WFAU post-processing error bits in J int 4   0 CODE_MISC
Post-processing error quality bit flags assigned in the WSA curation procedure for UHS data. From least to most significant byte in the 4-byte integer attribute byte 0 (bits 0 to 7) corresponds to information on generally innocuous conditions that are nonetheless potentially significant as regards the integrity of that detection; byte 1 (bits 8 to 15) corresponds to warnings; byte 2 (bits 16 to 23) corresponds to important warnings; and finally byte 3 (bits 24 to 31) corresponds to severe warnings:
ByteBitDetection quality issue Threshold or bit mask Applies to
DecimalHexadecimal
0 4 Deblended 16 0x00000010 All VDFS catalogues
0 6 Bad pixel(s) in default aperture 64 0x00000040 All VDFS catalogues
1 15 Source in poor flat field region 32768 0x00008000 All but mosaics
2 16 Close to saturated 65536 0x00010000 All VDFS catalogues (though deeps excluded prior to DR8)
2 17 Photometric calibration probably subject to systematic error 131072 0x00020000 GPS only
2 19 Possible crosstalk artefact/contamination 524288 0x00080000 All but GPS
2 22 Lies within a dither offset of the stacked frame boundary 4194304 0x00400000 All but mosaics
4 30 failed quantitative QC, i.e. seeing, ellipticity, zero-point and depth 1073741824 0x40000000 used in UHS
4 31 failed eyeball QC eg trailed, poor flat fielding etc 2147483648 0x80000000 used in UHS

In this way, the higher the error quality bit flag value, the more likely it is that the detection is spurious. The decimal threshold (column 4) gives the minimum value of the quality flag for a detection having the given condition (since other bits in the flag may be set also; the corresponding hexadecimal value, where each digit corresponds to 4 bits in the flag, can be easier to compute when writing SQL queries to test for a given condition). For example, to exclude all J band sources in the UHS having failed QC ones, include a predicate ... AND yppErrBits < 1073741824. See the SQL Cookbook and other online pages for further information.
jprobVar calVariability WSACalib Probability of variable from chi-square (and other data) real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jprobVar dxsVariability, udsVariability WSA Probability of variable from chi-square (and other data) real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jPsfMag calSource WSACalib Point source profile-fitted J mag real 4 mag -0.9999995e9 PHOT_MAG
jPsfMag dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource WSA Point source profile-fitted J mag real 4 mag -0.9999995e9 PHOT_MAG
jPsfMag reliableUdsSource, udsSource WSA Not available in SE output real 4 mag -0.9999995e9 PHOT_MAG
jPsfMag uhsSource, uhsSourceAll WSAUHS Point source profile-fitted J mag real 4 mag -0.9999995e9 PHOT_MAG
jPsfMagErr calSource WSACalib Error in point source profile-fitted J mag real 4 mag -0.9999995e9 ERROR
jPsfMagErr dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource WSA Error in point source profile-fitted J mag real 4 mag -0.9999995e9 ERROR
jPsfMagErr reliableUdsSource, udsSource WSA Not available in SE output real 4 mag -0.9999995e9 ERROR
jPsfMagErr uhsSource, uhsSourceAll WSAUHS Error in point source profile-fitted J mag real 4 mag -0.9999995e9 ERROR
jSeqNum calSource, calSynopticSource WSACalib the running number of the J detection int 4   -99999999 ID_NUMBER
jSeqNum dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource, udsSource WSA the running number of the J detection int 4   -99999999 ID_NUMBER
jSeqNum gcsSourceRemeasurement, gpsSourceRemeasurement WSA the running number of the J remeasurement int 4   -99999999 ID_NUMBER
jSeqNum uhsSource, uhsSourceAll WSAUHS the running number of the J detection int 4   -99999999 ID_NUMBER
jSerMag2D calSource WSACalib Extended source J mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
jSerMag2D dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource WSA Extended source J mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
jSerMag2D reliableUdsSource, udsSource WSA Not available in SE output real 4 mag -0.9999995e9 PHOT_MAG
jSerMag2D uhsSource, uhsSourceAll WSAUHS Extended source J mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
jSerMag2DErr calSource WSACalib Error in extended source J mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
jSerMag2DErr dxsJKsource, dxsSource, gcsPointSource, gcsSource, gcsZYJHKsource, reliableDxsSource, reliableGcsPointSource WSA Error in extended source J mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
jSerMag2DErr reliableUdsSource, udsSource WSA Not available in SE output real 4 mag -0.9999995e9 ERROR
jSerMag2DErr uhsSource, uhsSourceAll WSAUHS Error in extended source J mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
jskewness calVariability WSACalib Skewness in J band (see Sesar et al. 2007) real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jskewness dxsVariability, udsVariability WSA Skewness in J band (see Sesar et al. 2007) real 4   -0.9999995e9  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jtotalPeriod calVariability WSACalib total period of observations (last obs-first obs) real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
jtotalPeriod dxsVariability, udsVariability WSA total period of observations (last obs-first obs) real 4 days -0.9999995e9  
The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.
julianDayNum Multiframe WSA the Julian Day number of the UKIRT night int 4 Julian days   time.epoch
julianDayNum Multiframe WSACalib the Julian Day number of the UKIRT night int 4 Julian days   time.epoch
julianDayNum Multiframe WSATransit the Julian Day number of the UKIRT night int 4 Julian days   time.epoch
julianDayNum Multiframe WSAUHS the Julian Day number of the UKIRT night int 4 Julian days   time.epoch
julianDayNum MultiframeDetector WSA the Julian Day number of the UKIRT night {image primary HDU keyword: UTDATE} int 4 Julian days   time.epoch
julianDayNum MultiframeDetector WSACalib the Julian Day number of the UKIRT night {image primary HDU keyword: UTDATE} int 4 Julian days   time.epoch
julianDayNum MultiframeDetector WSATransit the Julian Day number of the UKIRT night {image primary HDU keyword: UTDATE} int 4 Julian days   time.epoch
julianDayNum MultiframeDetector WSAUHS the Julian Day number of the UKIRT night {image primary HDU keyword: UTDATE} int 4 Julian days   time.epoch
jVarClass calVariability WSACalib Classification of variability in this band smallint 2   -9999  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jVarClass dxsVariability, udsVariability WSA Classification of variability in this band smallint 2   -9999  
The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.
jXi calSource, calSynopticSource WSACalib Offset of J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
jXi dxsJKsource, gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableDxsSource, reliableGcsPointSource, reliableGpsPointSource, reliableUdsSource WSA Offset of J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
jXi dxsSource, gcsSource, gpsSource, udsSource WSA Offset of J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.
jXi uhsSource, uhsSourceAll WSAUHS Offset of J detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; UHS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want. NB: the master position is the position of the detection in the shortest passband in the set, rather than the ra/dec of the source as stored in source attributes of the same name. The former is used in the pairing process, while the latter is generally the optimally weighted mean position from an astrometric solution or other combinatorial process of all individual detection positions across the available passbands.


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29/06/2018