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### Glossary of WSA NonSurvey attributes (UKIDSSDR10)

##### 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

### Y

NameSchema TableDatabaseDescriptionTypeLengthUnitDefault ValueUnified Content Descriptor
y [nspid]Detection WSA NonSurvey Y coordinate of detection (SE: Y_IMAGE) {catalogue TType keyword: Y_coordinate}
Intensity-weighted isophotal centre-of-gravity in Y.
real 4 pixels   POS_PLATE_Y
y [nspid]Detection, [nspid]ListRemeasurement, [nspid]SatelliteDetection WSA NonSurvey Y coordinate of detection {catalogue TType keyword: Y_coordinate}
Intensity-weighted isophotal centre-of-gravity in Y.
real 4 pixels   POS_PLATE_Y
y [nspid]MapRemeasurement WSA NonSurvey Y coordinate of detection (SE: Y_IMAGE) {catalogue TType keyword: Y_coordinate}
Intensity-weighted isophotal centre-of-gravity in Y.
real 4 pixels   pos.cartesian.y;instr.plate
y [nspid]UKIDSSDetection WSA NonSurvey Y coordinate of detection real 4 pixels   POS_PLATE_Y
y_1AperMag3 [nspid]Source WSA NonSurvey Default point source Y_1 aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator
real 4 mag -0.9999995e9 PHOT_MAG
y_1AperMag3Err [nspid]Source WSA NonSurvey Error in default point source Y_1 mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
y_1AperMag4 [nspid]Source WSA NonSurvey Point source Y_1 aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
y_1AperMag4Err [nspid]Source WSA NonSurvey Error in point source Y_1 mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
y_1AperMag6 [nspid]Source WSA NonSurvey Point source Y_1 aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
y_1AperMag6Err [nspid]Source WSA NonSurvey Error in point source Y_1 mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
y_1Class [nspid]Source WSA NonSurvey discrete image classification flag in Y_1 smallint 2   -9999 CLASS_MISC
y_1ClassStat [nspid]Source WSA NonSurvey N(0,1) stellarness-of-profile statistic in Y_1 real 4   -0.9999995e9 STAT_PROP
y_1Deblend [nspid]Source WSA NonSurvey placeholder flag indicating parent/child relation in Y_1 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.
y_1Ell [nspid]Source WSA NonSurvey 1-b/a, where a/b=semi-major/minor axes in Y_1 real 4   -0.9999995e9 PHYS_ELLIPTICITY
y_1eNum [nspid]MergeLog WSA NonSurvey the extension number of this Y_1 frame tinyint 1     NUMBER
y_1ErrBits [nspid]Source WSA NonSurvey processing warning/error bitwise flags in Y_1 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.
y_1Eta [nspid]Source WSA NonSurvey Offset of Y_1 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.
y_1Gausig [nspid]Source WSA NonSurvey RMS of axes of ellipse fit in Y_1 real 4 pixels -0.9999995e9 MORPH_PARAM
y_1HallMag [nspid]Source WSA NonSurvey Total point source Y_1 mag real 4 mag -0.9999995e9 PHOT_MAG
y_1HallMagErr [nspid]Source WSA NonSurvey Error in total point source Y_1 mag real 4 mag -0.9999995e9 ERROR
y_1mfID [nspid]MergeLog WSA NonSurvey the UID of the relevant Y_1 multiframe bigint 8     ID_FRAME
y_1mj_1Ext [nspid]Source WSA NonSurvey Extended source colour Y_1-J_1 (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.
y_1mj_1ExtErr [nspid]Source WSA NonSurvey Error on extended source colour Y_1-J_1 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.
y_1mj_1Pnt [nspid]Source WSA NonSurvey Point source colour Y_1-J_1 (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.
y_1mj_1PntErr [nspid]Source WSA NonSurvey Error on point source colour Y_1-J_1 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.
y_1PA [nspid]Source WSA NonSurvey ellipse fit celestial orientation in Y_1 real 4 Degrees -0.9999995e9 POS_POS-ANG
y_1PetroMag [nspid]Source WSA NonSurvey Extended source Y_1 mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
y_1PetroMagErr [nspid]Source WSA NonSurvey Error in extended source Y_1 mag (Petrosian) real 4 mag -0.9999995e9 ERROR
y_1ppErrBits [nspid]Source WSA NonSurvey additional WFAU post-processing error bits in Y_1 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:
 Byte Bit Detection quality issue Threshold or bit mask Applies to Decimal Hexadecimal 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.
y_1PsfMag [nspid]Source WSA NonSurvey Point source profile-fitted Y_1 mag real 4 mag -0.9999995e9 PHOT_MAG
y_1PsfMagErr [nspid]Source WSA NonSurvey Error in point source profile-fitted Y_1 mag real 4 mag -0.9999995e9 ERROR
y_1SeqNum [nspid]Source WSA NonSurvey the running number of the Y_1 detection int 4   -99999999 ID_NUMBER
y_1SerMag2D [nspid]Source WSA NonSurvey Extended source Y_1 mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
y_1SerMag2DErr [nspid]Source WSA NonSurvey Error in extended source Y_1 mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
y_1Xi [nspid]Source WSA NonSurvey Offset of Y_1 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.
y_2AperMag3 [nspid]Source WSA NonSurvey Default point source Y_2 aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator
real 4 mag -0.9999995e9 PHOT_MAG
y_2AperMag3Err [nspid]Source WSA NonSurvey Error in default point source Y_2 mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
y_2AperMag4 [nspid]Source WSA NonSurvey Point source Y_2 aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
y_2AperMag4Err [nspid]Source WSA NonSurvey Error in point source Y_2 mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
y_2AperMag6 [nspid]Source WSA NonSurvey Point source Y_2 aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
y_2AperMag6Err [nspid]Source WSA NonSurvey Error in point source Y_2 mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
y_2Class [nspid]Source WSA NonSurvey discrete image classification flag in Y_2 smallint 2   -9999 CLASS_MISC
y_2ClassStat [nspid]Source WSA NonSurvey N(0,1) stellarness-of-profile statistic in Y_2 real 4   -0.9999995e9 STAT_PROP
y_2Deblend [nspid]Source WSA NonSurvey placeholder flag indicating parent/child relation in Y_2 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.
y_2Ell [nspid]Source WSA NonSurvey 1-b/a, where a/b=semi-major/minor axes in Y_2 real 4   -0.9999995e9 PHYS_ELLIPTICITY
y_2eNum [nspid]MergeLog WSA NonSurvey the extension number of this Y_2 frame tinyint 1     NUMBER
y_2ErrBits [nspid]Source WSA NonSurvey processing warning/error bitwise flags in Y_2 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.
y_2Eta [nspid]Source WSA NonSurvey Offset of Y_2 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.
y_2Gausig [nspid]Source WSA NonSurvey RMS of axes of ellipse fit in Y_2 real 4 pixels -0.9999995e9 MORPH_PARAM
y_2HallMag [nspid]Source WSA NonSurvey Total point source Y_2 mag real 4 mag -0.9999995e9 PHOT_MAG
y_2HallMagErr [nspid]Source WSA NonSurvey Error in total point source Y_2 mag real 4 mag -0.9999995e9 ERROR
y_2mfID [nspid]MergeLog WSA NonSurvey the UID of the relevant Y_2 multiframe bigint 8     ID_FRAME
y_2mhExt [nspid]Source WSA NonSurvey Extended source colour Y_2-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.
y_2mhExtErr [nspid]Source WSA NonSurvey Error on extended source colour Y_2-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.
y_2mhPnt [nspid]Source WSA NonSurvey Point source colour Y_2-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.
y_2mhPntErr [nspid]Source WSA NonSurvey Error on point source colour Y_2-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.
y_2PA [nspid]Source WSA NonSurvey ellipse fit celestial orientation in Y_2 real 4 Degrees -0.9999995e9 POS_POS-ANG
y_2PetroMag [nspid]Source WSA NonSurvey Extended source Y_2 mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
y_2PetroMagErr [nspid]Source WSA NonSurvey Error in extended source Y_2 mag (Petrosian) real 4 mag -0.9999995e9 ERROR
y_2ppErrBits [nspid]Source WSA NonSurvey additional WFAU post-processing error bits in Y_2 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:
 Byte Bit Detection quality issue Threshold or bit mask Applies to Decimal Hexadecimal 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.
y_2PsfMag [nspid]Source WSA NonSurvey Point source profile-fitted Y_2 mag real 4 mag -0.9999995e9 PHOT_MAG
y_2PsfMagErr [nspid]Source WSA NonSurvey Error in point source profile-fitted Y_2 mag real 4 mag -0.9999995e9 ERROR
y_2SeqNum [nspid]Source WSA NonSurvey the running number of the Y_2 detection int 4   -99999999 ID_NUMBER
y_2SerMag2D [nspid]Source WSA NonSurvey Extended source Y_2 mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
y_2SerMag2DErr [nspid]Source WSA NonSurvey Error in extended source Y_2 mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
y_2Xi [nspid]Source WSA NonSurvey Offset of Y_2 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.
yAperMag1 [nspid]SynopticSource WSA NonSurvey Extended source Y aperture corrected mag (0.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag1Err [nspid]SynopticSource WSA NonSurvey Error in extended source Y mag (0.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag2 [nspid]SynopticSource WSA NonSurvey Extended source Y aperture corrected mag (1.4 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag2Err [nspid]SynopticSource WSA NonSurvey Error in extended source Y mag (1.4 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag3 [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Default point/extended source Y aperture corrected mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag3 [nspid]Source WSA NonSurvey Default point/extended source Y aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator
real 4 mag -0.9999995e9 PHOT_MAG
yAperMag3 [nspid]Source WSA NonSurvey Default point source Y aperture corrected mag (2.0 arcsec aperture diameter)
If in doubt use this flux estimator
real 4 mag -0.9999995e9 PHOT_MAG
yAperMag3Err [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Error in default point/extended source Y mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag3Err [nspid]Source WSA NonSurvey Error in default point source Y mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag4 [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Extended source Y aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag4 [nspid]Source WSA NonSurvey Point source Y aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag4Err [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Error in extended source Y mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag4Err [nspid]Source WSA NonSurvey Error in point source Y mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag5 [nspid]SynopticSource WSA NonSurvey Extended source Y aperture corrected mag (4.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag5Err [nspid]SynopticSource WSA NonSurvey Error in extended source Y mag (4.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag6 [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Extended source Y aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag6 [nspid]Source WSA NonSurvey Point source Y aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG
yAperMag6Err [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Error in extended source Y mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yAperMag6Err [nspid]Source WSA NonSurvey Error in point source Y mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR
yaStratAst [nspid]VarFrameSetInfo WSA NonSurvey Strateva parameter, a, in fit to astrometric rms vs magnitude in Y 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.
yaStratAst [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c0 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to astrometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
yaStratPht [nspid]VarFrameSetInfo WSA NonSurvey Strateva parameter, a, in fit to photometric rms vs magnitude in Y 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.
yaStratPht [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c0 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to photometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
ybestAper [nspid]Variability WSA NonSurvey Best aperture (1-6) for photometric statistics in the Y 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)
ybStratAst [nspid]VarFrameSetInfo WSA NonSurvey Strateva parameter, b, in fit to astrometric rms vs magnitude in Y 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.
ybStratAst [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c1 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to astrometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
ybStratPht [nspid]VarFrameSetInfo WSA NonSurvey Strateva parameter, b, in fit to photometric rms vs magnitude in Y 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.
ybStratPht [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c1 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to photometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
ychiSqAst [nspid]VarFrameSetInfo WSA NonSurvey Goodness of fit of Strateva function to astrometric data in Y 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.
ychiSqAst [nspid]VarFrameSetInfo WSA NonSurvey Goodness of fit of Strateva function to astrometric data in Y band real 4   -0.9999995e9 stat.fit.goodness;em.IR.NIR
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.
ychiSqpd [nspid]Variability WSA NonSurvey 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.
ychiSqPht [nspid]VarFrameSetInfo WSA NonSurvey Goodness of fit of Strateva function to photometric data in Y 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.
yClass [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SourceRemeasurement, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey discrete image classification flag in Y smallint 2   -9999 CLASS_MISC
yClassStat [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SourceRemeasurement, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey N(0,1) stellarness-of-profile statistic in Y real 4   -0.9999995e9 STAT_PROP
ycStratAst [nspid]VarFrameSetInfo WSA NonSurvey Strateva parameter, c, in fit to astrometric rms vs magnitude in Y 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.
ycStratAst [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c2 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to astrometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
ycStratPht [nspid]VarFrameSetInfo WSA NonSurvey Strateva parameter, c, in fit to photometric rms vs magnitude in Y 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.
ycStratPht [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c2 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to photometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
yDeblend [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]SourceRemeasurement, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey placeholder flag indicating parent/child relation in Y int 4   -99999999 CODE_MISC
yDeblend [nspid]Source WSA NonSurvey placeholder flag indicating parent/child relation in Y 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.
ydStratAst [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c3 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to astrometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
ydStratPht [nspid]VarFrameSetInfo WSA NonSurvey Parameter, c0 from Ferreira-Lopes & Cross 2017, Eq. 18, in fit to photometric rms vs magnitude in Y band. real 4   -0.9999995e9 stat.fit.param;em.IR.NIR
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.
yEll [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SourceRemeasurement, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey 1-b/a, where a/b=semi-major/minor axes in Y real 4   -0.9999995e9 PHYS_ELLIPTICITY
yeNum [nspid]MergeLog, [nspid]SynopticMergeLog, [nspid]ZYJHKmergeLog WSA NonSurvey the extension number of this Y frame tinyint 1     NUMBER
yeNum [nspid]YJHKmergeLog WSA NonSurvey the extension number of this frame tinyint 1     NUMBER
yErr [nspid]Detection WSA NonSurvey Error in Y coordinate (SE: ERRY2_IMAGE½) {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error.
real 4 pixels   ERROR
yErr [nspid]Detection, [nspid]ListRemeasurement, [nspid]SatelliteDetection WSA NonSurvey Error in Y coordinate {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error.
real 4 pixels   ERROR
yErr [nspid]MapRemeasurement WSA NonSurvey Error in Y coordinate (SE: ERRY2_IMAGE½) {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error.
real 4 pixels   stat.error
yErr [nspid]UKIDSSDetection WSA NonSurvey Error in Y coordinate real 4 pixels   ERROR
yErrBits [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]SourceRemeasurement, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey processing warning/error bitwise flags in Y int 4   -99999999 CODE_MISC
yErrBits [nspid]Source, [nspid]SynopticSource WSA NonSurvey processing warning/error bitwise flags in Y 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.
yEta [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Offset of Y detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF
yEta [nspid]Source, [nspid]SynopticSource WSA NonSurvey Offset of Y 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.
yexpML [nspid]VarFrameSetInfo WSA NonSurvey Expected magnitude limit of frameSet in this in Y 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.
yExpRms [nspid]Variability WSA NonSurvey Rms calculated from polynomial fit to modal RMS as a function of magnitude in Y 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.
yExtent [nspid]RequiredMosaicTopLevel WSA NonSurvey The angular extent of the mosaic image in the y-direction real 4 degrees   ??
yGausig [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SourceRemeasurement, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey RMS of axes of ellipse fit in Y real 4 pixels -0.9999995e9 MORPH_PARAM
yHallMag [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Total point source Y mag real 4 mag -0.9999995e9 PHOT_MAG
yHallMagErr [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Error in total point source Y mag real 4 mag -0.9999995e9 ERROR
yIntRms [nspid]Variability WSA NonSurvey Intrinsic rms in Y-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.
yisDefAst [nspid]VarFrameSetInfo WSA NonSurvey Use a default model for the astrometric noise in Y band. tinyint 1   0
yisDefAst [nspid]VarFrameSetInfo WSA NonSurvey Use a default model for the astrometric noise in Y band. tinyint 1   0 meta.code;em.IR.NIR
yisDefPht [nspid]VarFrameSetInfo WSA NonSurvey Use a default model for the photometric noise in Y band. tinyint 1   0
yjiWS [nspid]Variability WSA NonSurvey Welch-Stetson statistic between Y and J. 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.
yMag [nspid]SourceRemeasurement WSA NonSurvey Y mag (as appropriate for this merged source) real 4 mag -0.9999995e9 PHOT_MAG
yMagErr [nspid]SourceRemeasurement WSA NonSurvey Error in Y mag real 4 mag -0.9999995e9 ERROR
yMagMAD [nspid]Variability WSA NonSurvey Median Absolute Deviation of Y 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.
yMagRms [nspid]Variability WSA NonSurvey rms of Y 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.
ymaxCadence [nspid]Variability WSA NonSurvey 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.
yMaxMag [nspid]Variability WSA NonSurvey Maximum magnitude in Y 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.
ymeanMag [nspid]Variability WSA NonSurvey Mean Y 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.
ymedCadence [nspid]Variability WSA NonSurvey 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.
ymedianMag [nspid]Variability WSA NonSurvey Median Y 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.
ymfID [nspid]MergeLog, [nspid]SynopticMergeLog, [nspid]ZYJHKmergeLog WSA NonSurvey the UID of the relevant Y multiframe bigint 8     ID_FRAME
ymfID [nspid]YJHKmergeLog WSA NonSurvey the UID of the relevant multiframe bigint 8     ID_FRAME
ymhExt [nspid]Source WSA NonSurvey Extended source colour Y-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.
ymhExtErr [nspid]Source WSA NonSurvey Error on extended source colour Y-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.
ymhPnt [nspid]Source WSA NonSurvey Point source colour Y-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.
ymhPntErr [nspid]Source WSA NonSurvey Error on point source colour Y-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.
yminCadence [nspid]Variability WSA NonSurvey 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.
yMinMag [nspid]Variability WSA NonSurvey Minimum magnitude in Y 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.
ymj [nspid]SourceRemeasurement WSA NonSurvey Default colour Y-J (using appropriate mags) real 4 mag   PHOT_COLOR
ymj_1Ext [nspid]ExtendedSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]YJHKsource WSA NonSurvey Extended source colour Y-J (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
ymj_1Ext [nspid]Source WSA NonSurvey Extended source colour Y-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.
ymj_1ExtErr [nspid]ExtendedSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]YJHKsource WSA NonSurvey Error on extended source colour Y-J real 4 mag -0.9999995e9 ERROR
ymj_1ExtErr [nspid]Source WSA NonSurvey Error on extended source colour Y-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.
ymj_1Pnt [nspid]ExtendedSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]YJHKsource WSA NonSurvey Point source colour Y-J (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
ymj_1Pnt [nspid]Source WSA NonSurvey Point source colour Y-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.
ymj_1PntErr [nspid]ExtendedSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]YJHKsource WSA NonSurvey Error on point source colour Y-J real 4 mag -0.9999995e9 ERROR
ymj_1PntErr [nspid]Source WSA NonSurvey Error on point source colour Y-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.
ymjErr [nspid]SourceRemeasurement WSA NonSurvey Error on colour Y-J real 4 mag   ERROR
ymjExt [nspid]GcsPointSource, [nspid]PointSource, [nspid]ZYJHKsource WSA NonSurvey Extended source colour Y-J (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
ymjExt [nspid]Source WSA NonSurvey Extended source colour Y-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.
ymjExtErr [nspid]GcsPointSource, [nspid]PointSource, [nspid]ZYJHKsource WSA NonSurvey Error on extended source colour Y-J real 4 mag -0.9999995e9 ERROR
ymjExtErr [nspid]Source WSA NonSurvey Error on extended source colour Y-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.
ymjPnt [nspid]GcsPointSource, [nspid]PointSource, [nspid]ZYJHKsource WSA NonSurvey Point source colour Y-J (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR
ymjPnt [nspid]Source, [nspid]SynopticSource WSA NonSurvey Point source colour Y-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.
ymjPntErr [nspid]GcsPointSource, [nspid]PointSource, [nspid]ZYJHKsource WSA NonSurvey Error on point source colour Y-J real 4 mag -0.9999995e9 ERROR
ymjPntErr [nspid]Source, [nspid]SynopticSource WSA NonSurvey Error on point source colour Y-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.
ymkExt [nspid]Source WSA NonSurvey Extended source colour Y-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.
ymkExtErr [nspid]Source WSA NonSurvey Error on extended source colour Y-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.
ymkPnt [nspid]Source WSA NonSurvey Point source colour Y-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.
ymkPntErr [nspid]Source WSA NonSurvey Error on point source colour Y-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.
yndof [nspid]Variability WSA NonSurvey 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.
ynDofAst [nspid]VarFrameSetInfo WSA NonSurvey Number of degrees of freedom of astrometric fit in Y 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.
ynDofAst [nspid]VarFrameSetInfo WSA NonSurvey Number of degrees of freedom of astrometric fit in Y band. smallint 2   -9999 stat.fit.dof;stat.param;em.IR.NIR
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.
ynDofPht [nspid]VarFrameSetInfo WSA NonSurvey Number of degrees of freedom of photometric fit in Y 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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y 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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u05bj1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u06bh22Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u08a15Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u08bj10Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u09ak1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u09bd1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u09bj2Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u09bk1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u09bk2Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u10a6Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u10ad4Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u10ah99Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u10ak1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u10ak2Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u10bk1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u10bk2Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u11ak3Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u11bk1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u11bk2Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u11bk3Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u11bk4Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u11bk4bDetection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u12ak1Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u12ak2Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u12ak3Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u12ak5Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u12bk3Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u14bua06Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u14bua17Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u15ah02Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u15bh01Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u15bua19Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by u16aua18Detection.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.
ynFlaggedObs [nspid]Variability WSA NonSurvey Number of detections in Y band flagged as potentially spurious by userv1677Detection.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.
ynGoodObs [nspid]Variability WSA NonSurvey Number of good detections in Y 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.
yNgt3sig [nspid]Variability WSA NonSurvey Number of good detections in Y-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.
yNgt3sig [nspid]Variability WSA NonSurvey Number of good detections in Y-band that are more than 3 sigma deviations (yAperMagN < (yMeanMag-3*yMagRms) 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.
ynMissingObs [nspid]Variability WSA NonSurvey Number of Y 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.
yObjID [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey DEPRECATED (do not use) bigint 8   -99999999 ID_NUMBER
yObjID [nspid]Source, [nspid]SourceRemeasurement 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.
yOverlap [nspid]RequiredMosaicTopLevel WSA NonSurvey The overlap between adjacent mosaics in the y-direction real 4 degrees   ??
yPA [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SourceRemeasurement, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey ellipse fit celestial orientation in Y real 4 Degrees -0.9999995e9 POS_POS-ANG
yPetroMag [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Extended source Y mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG
yPetroMagErr [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Error in extended source Y mag (Petrosian) real 4 mag -0.9999995e9 ERROR
yPixSize [nspid]CurrentAstrometry, [nspid]PreviousAstrometry WSA NonSurvey Angular size of pixels in Y real 4 Arcseconds -0.9999995e9 pos.angDistance
yppErrBits [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]SourceRemeasurement, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey additional WFAU post-processing error bits in Y int 4   0 CODE_MISC
yppErrBits [nspid]Source, [nspid]SynopticSource WSA NonSurvey additional WFAU post-processing error bits in Y 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:
 Byte Bit Detection quality issue Threshold or bit mask Applies to Decimal Hexadecimal 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.
yprobVar [nspid]Variability WSA NonSurvey 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.
yPsfMag [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Point source profile-fitted Y mag real 4 mag -0.9999995e9 PHOT_MAG
yPsfMagErr [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Error in point source profile-fitted Y mag real 4 mag -0.9999995e9 ERROR
ySeqNum [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]SynopticSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey the running number of the Y detection int 4   -99999999 ID_NUMBER
ySeqNum [nspid]SourceRemeasurement WSA NonSurvey the running number of the Y remeasurement int 4   -99999999 ID_NUMBER
ySerMag2D [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Extended source Y mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG
ySerMag2DErr [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]Source, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Error in extended source Y mag (profile-fitted) real 4 mag -0.9999995e9 ERROR
ySize [nspid]MultiframeDetector WSA NonSurvey Corresponding image size (Y); value only available if catalogue file exists {catalogue extension keyword:  NYOUT} int 4   -99999999 meta.number
yskewness [nspid]Variability WSA NonSurvey Skewness in Y 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.
ytotalPeriod [nspid]Variability WSA NonSurvey 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.
yVarClass [nspid]Variability WSA NonSurvey 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.
yXi [nspid]ExtendedSource, [nspid]GcsPointSource, [nspid]LasPointSource, [nspid]PointSource, [nspid]YJHKsource, [nspid]ZYJHKsource WSA NonSurvey Offset of Y detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF
yXi [nspid]Source, [nspid]SynopticSource WSA NonSurvey Offset of Y 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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