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Glossary of WSA NonSurvey attributes (UKIDSSDR5)

This Glossary alphabetically lists all attributes used in the WSA NonSurvey database(s) held in the WSA. If you would like to have more information about the schema tables please use the 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

Z

NameSchema TableDatabaseDescriptionTypeLengthUnitDefault ValueUnified Content Descriptor
z11 [nspid]Multiframe WSA NonSurvey Spherical: Z11 {image primary HDU keyword: Z11} real 4   -0.9999995e9  
z7 [nspid]Multiframe WSA NonSurvey Coma: Z7 {image primary HDU keyword: Z7} real 4   -0.9999995e9  
z8 [nspid]Multiframe WSA NonSurvey Coma: Z8 {image primary HDU keyword: Z8} real 4   -0.9999995e9  
zAperMag3 [nspid]Source WSA NonSurvey Default point/extended source Z aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator
real 4 mag -0.9999995e9 PHOT_MAG
zAperMag3Err [nspid]Source WSA NonSurvey Error in default point/extended source Z mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
zAperMag4 [nspid]Source WSA NonSurvey Extended source Z aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
zAperMag4Err [nspid]Source WSA NonSurvey Error in extended source Z mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
zAperMag6 [nspid]Source WSA NonSurvey Extended source Z aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
zAperMag6Err [nspid]Source WSA NonSurvey Error in extended source Z mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
zClass [nspid]Source WSA NonSurvey discrete image classification flag in Z smallint 2   -9999 CLASS_MISC
zClassStat [nspid]Source WSA NonSurvey N(0,1) stellarness-of-profile statistic in Z real 4   -0.9999995e9 STAT_PROP
zDeblend [nspid]Source WSA NonSurvey placeholder flag indicating parent/child relation in Z 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.
zEll [nspid]Source WSA NonSurvey 1-b/a, where a/b=semi-major/minor axes in Z real 4   -0.9999995e9 PHYS_ELLIPTICITY
zeNum [nspid]MergeLog WSA NonSurvey the extension number of this Z detector tinyint 1     NUMBER
zErrBits [nspid]Source WSA NonSurvey processing warning/error bitwise flags in Z int 4   -99999999 CODE_MISC
zEta [nspid]Source WSA NonSurvey Offset of Z 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; 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.
zGausig [nspid]Source WSA NonSurvey RMS of axes of ellipse fit in Z real 4 pixels -0.9999995e9 MORPH_PARAM
zHallMag [nspid]Source WSA NonSurvey Total point source Z mag real 4 mag -0.9999995e9 PHOT_MAG
zHallMagErr [nspid]Source WSA NonSurvey Error in total point source Z mag real 4 mag -0.9999995e9 ERROR
zmfID [nspid]MergeLog WSA NonSurvey the UID of the relevant Z multiframe bigint 8     ID_FRAME
zmjExt [nspid]Source WSA NonSurvey Extended source colour Z-J (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.
zmjExtErr [nspid]Source WSA NonSurvey Error on extended source colour Z-J 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.
zmjPnt [nspid]Source WSA NonSurvey Point source colour Z-J (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.
zmjPntErr [nspid]Source WSA NonSurvey Error on point source colour Z-J 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.
zObjID [nspid]Source WSA NonSurvey 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.
zone [nspid]ExternalSurveyTable WSA NonSurvey default (0) or special (n) zone smallint 2     ID_REGION
zPA [nspid]Source WSA NonSurvey ellipse fit celestial orientation in Z real 4 Degrees -0.9999995e9 POS_POS-ANG
zPetroMag [nspid]Source WSA NonSurvey Extended source Z mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
zPetroMagErr [nspid]Source WSA NonSurvey Error in extended source Z mag (Petrosian) real 4 mag -0.9999995e9 ERROR
zppErrBits [nspid]Source WSA NonSurvey additional WFAU post-processing error bits in Z int 4   0 CODE_MISC
zPsfMag [nspid]Source WSA NonSurvey Point source profile-fitted Z mag real 4 mag -0.9999995e9 PHOT_MAG
zPsfMagErr [nspid]Source WSA NonSurvey Error in point source profile-fitted Z mag real 4 mag -0.9999995e9 ERROR
zSeqNum [nspid]Source WSA NonSurvey the running number of the Z detection int 4   -99999999 ID_NUMBER
zSerMag2D [nspid]Source WSA NonSurvey Extended source Z mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
zSerMag2DErr [nspid]Source WSA NonSurvey Error in extended source Z mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
zXi [nspid]Source WSA NonSurvey Offset of Z 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; 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.



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30/04/2009