WSA Browser

Glossary of WSA attributes

This Glossary alphabetically lists all attributes used in the UKIDSSDR11 database(s) held in the WSA. If you would like to have more information about the schema tables please use the UKIDSSDR11 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

Name Schema Table Database Description Type Length Unit Default Value Unified Content Descriptor

y UKIDSSDetection WSA Y coordinate of detection real 4 pixels POS_PLATE_Y

y allwise_sc WISE Unit sphere position y value float 8

y calDetection WSACalib Y coordinate of detection {catalogue TType keyword: Y_coordinate}
Intensity-weighted isophotal centre-of-gravity in Y. real 4 pixels POS_PLATE_Y

y dxsDetection, gcsDetection, gpsDetection, lasDetection WSA Y coordinate of detection {catalogue TType keyword: Y_coordinate}
Intensity-weighted isophotal centre-of-gravity in Y. real 4 pixels POS_PLATE_Y

y lasMapRemeasurement WSA 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 ptsDetection WSATransit Y coordinate of detection {catalogue TType keyword: Y_coordinate}
Intensity-weighted isophotal centre-of-gravity in Y. real 4 pixels POS_PLATE_Y

y udsDetection WSA 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 uhsDetection, uhsDetectionAll WSAUHS Y coordinate of detection {catalogue TType keyword: Y_coordinate}
Intensity-weighted isophotal centre-of-gravity in Y. real 4 pixels POS_PLATE_Y

y_coadd twomass_xsc 2MASS y (in-scan) position (coadd coord.). real 4 arcsec INST_POS

Y_IMAGE mgcDetection MGC Object y position real 4 pixel

Y_OFF mgcGalaxyStruct MGC Y offset of Galaxy Centre real 4 99.99

Y_OFFm mgcGalaxyStruct MGC Y offset error (-) real 4 99.99

Y_OFFp mgcGalaxyStruct MGC Y offset error (+) real 4 99.99

yAperJky3 lasYselJSourceRemeasurement WSA Default point source Y aperture corrected (2.0 arcsec aperture diameter) calibrated flux
If in doubt use this flux estimator real 4 jansky -0.9999995e9 phot.flux

yAperJky3Err lasYselJSourceRemeasurement WSA Error in default point/extended source Y (2.0 arcsec aperture diameter) calibrated flux real 4 jansky -0.9999995e9 stat.error

yAperJky4 lasYselJSourceRemeasurement WSA Point source Y aperture corrected (2.8 arcsec aperture diameter) calibrated flux real 4 jansky -0.9999995e9 phot.flux

yAperJky4Err lasYselJSourceRemeasurement WSA Error in point/extended source Y (2.8 arcsec aperture diameter) calibrated flux real 4 jansky -0.9999995e9 stat.error

yAperJky6 lasYselJSourceRemeasurement WSA Point source Y aperture corrected (5.7 arcsec aperture diameter) calibrated flux real 4 jansky -0.9999995e9 phot.flux

yAperJky6Err lasYselJSourceRemeasurement WSA Error in point/extended source Y (5.7 arcsec aperture diameter) calibrated flux real 4 jansky -0.9999995e9 stat.error

yAperJkyNoAperCorr3 lasYselJSourceRemeasurement WSA Default extended source Y (2.0 arcsec aperture diameter, but no aperture correction applied) aperture calibrated flux
If in doubt use this flux estimator real 4 jansky -0.9999995e9 phot.flux

yAperJkyNoAperCorr4 lasYselJSourceRemeasurement WSA Extended source Y (2.8 arcsec aperture diameter, but no aperture correction applied) aperture calibrated flux real 4 jansky -0.9999995e9 phot.flux

yAperJkyNoAperCorr6 lasYselJSourceRemeasurement WSA Extended source Y (5.7 arcsec aperture diameter, but no aperture correction applied) aperture calibrated flux real 4 jansky -0.9999995e9 phot.flux

yAperLup3 lasYselJSourceRemeasurement WSA Default point source Y aperture corrected (2.0 arcsec aperture diameter) luptitude
If in doubt use this flux estimator real 4 lup -0.9999995e9 phot.lup

yAperLup3Err lasYselJSourceRemeasurement WSA Error in default point/extended source Y (2.0 arcsec aperture diameter) luptitude real 4 lup -0.9999995e9 stat.error

yAperLup4 lasYselJSourceRemeasurement WSA Point source Y aperture corrected (2.8 arcsec aperture diameter) luptitude real 4 lup -0.9999995e9 phot.lup

yAperLup4Err lasYselJSourceRemeasurement WSA Error in point/extended source Y (2.8 arcsec aperture diameter) luptitude real 4 lup -0.9999995e9 stat.error

yAperLup6 lasYselJSourceRemeasurement WSA Point source Y aperture corrected (5.7 arcsec aperture diameter) luptitude real 4 lup -0.9999995e9 phot.lup

yAperLup6Err lasYselJSourceRemeasurement WSA Error in point/extended source Y (5.7 arcsec aperture diameter) luptitude real 4 lup -0.9999995e9 stat.error

yAperLupNoAperCorr3 lasYselJSourceRemeasurement WSA Default extended source Y (2.0 arcsec aperture diameter, but no aperture correction applied) aperture luptitude
If in doubt use this flux estimator real 4 lup -0.9999995e9 phot.lup

yAperLupNoAperCorr4 lasYselJSourceRemeasurement WSA Extended source Y (2.8 arcsec aperture diameter, but no aperture correction applied) aperture luptitude real 4 lup -0.9999995e9 phot.lup

yAperLupNoAperCorr6 lasYselJSourceRemeasurement WSA Extended source Y (5.7 arcsec aperture diameter, but no aperture correction applied) aperture luptitude real 4 lup -0.9999995e9 phot.lup

yAperMag1 calSynopticSource WSACalib Extended source Y aperture corrected mag (1.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag1Err calSynopticSource WSACalib Error in extended source Y mag (1.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag2 calSynopticSource WSACalib Extended source Y aperture corrected mag (1.4 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag2Err calSynopticSource WSACalib Error in extended source Y mag (1.4 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag3 calSource WSACalib 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 calSynopticSource WSACalib Default point/extended source Y aperture corrected mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag3 gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Default point source Y aperture corrected mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag3 gcsSource, lasSource WSA 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

yAperMag3 lasYselJSourceRemeasurement WSA Default point source Y aperture corrected (2.0 arcsec aperture diameter)
If in doubt use this flux estimator real 4 mag -0.9999995e9 phot.mag

yAperMag3Err calSource, calSynopticSource WSACalib Error in default point/extended source Y mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag3Err gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error in default point source Y mag (2.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag3Err lasYselJSourceRemeasurement WSA Error in default point/extended source Y (2.0 arcsec aperture diameter) magnitude real 4 mag -0.9999995e9 stat.error

yAperMag4 calSource, calSynopticSource WSACalib Extended source Y aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag4 gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Point source Y aperture corrected mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag4 lasYselJSourceRemeasurement WSA Point source Y aperture corrected (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 phot.mag

yAperMag4Err calSource, calSynopticSource WSACalib Error in extended source Y mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag4Err gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error in point source Y mag (2.8 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag4Err lasYselJSourceRemeasurement WSA Error in point/extended source Y (2.8 arcsec aperture diameter) magnitude real 4 mag -0.9999995e9 stat.error

yAperMag5 calSynopticSource WSACalib Extended source Y aperture corrected mag (4.0 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag5Err calSynopticSource WSACalib Error in extended source Y mag (4.0 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag6 calSource WSACalib Extended source Y aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag6 gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Point source Y aperture corrected mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 PHOT_MAG

yAperMag6 lasYselJSourceRemeasurement WSA Point source Y aperture corrected (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 phot.mag

yAperMag6Err calSource WSACalib Error in extended source Y mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag6Err gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error in point source Y mag (5.7 arcsec aperture diameter) real 4 mag -0.9999995e9 ERROR

yAperMag6Err lasYselJSourceRemeasurement WSA Error in point/extended source Y (5.7 arcsec aperture diameter) magnitude real 4 mag -0.9999995e9 stat.error

yAperMagNoAperCorr3 lasYselJSourceRemeasurement WSA Default extended source Y (2.0 arcsec aperture diameter, but no aperture correction applied) aperture magnitude
If in doubt use this flux estimator real 4 mag -0.9999995e9 phot.mag

yAperMagNoAperCorr4 lasYselJSourceRemeasurement WSA Extended source Y (2.8 arcsec aperture diameter, but no aperture correction applied) aperture magnitude real 4 mag -0.9999995e9 phot.mag

yAperMagNoAperCorr6 lasYselJSourceRemeasurement WSA Extended source Y (5.7 arcsec aperture diameter, but no aperture correction applied) aperture magnitude real 4 mag -0.9999995e9 phot.mag

yApFillFac StackObjectAttributes PS1DR2 Aperture fill factor from y filter stack detection. real 4 -999

yApFlux StackObjectAttributes PS1DR2 Aperture flux from y filter stack detection. real 4 Janskys -999

yApFluxErr StackObjectAttributes PS1DR2 Error in aperture flux from y filter stack detection. real 4 Janskys -999

yApMag StackObjectThin PS1DR2 Aperture magnitude from y filter stack detection. real 4 AB magnitudes -999

yApMagErr StackObjectThin PS1DR2 Error in aperture magnitude from y filter stack detection. real 4 AB magnitudes -999

yApRadius StackObjectAttributes PS1DR2 Aperture radius for y filter stack detection. real 4 arcsec -999

yaStratAst calVarFrameSetInfo WSACalib 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.

yaStratPht calVarFrameSetInfo WSACalib 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.

yAverageConf lasYselJSourceRemeasurement WSA average confidence in 2 arcsec diameter default aperture (aper3) Y real 4 -0.9999995e9 stat.likelihood;em.IR.NIR

ybestAper calVariability WSACalib 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 calVarFrameSetInfo WSACalib 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.

ybStratPht calVarFrameSetInfo WSACalib 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.

ychiSqAst calVarFrameSetInfo WSACalib 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.

ychiSqpd calVariability WSACalib Chi square (per degree of freedom) fit to data (mean and expected rms) real 4 -0.9999995e9

The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.

ychiSqPht calVarFrameSetInfo WSACalib 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 calSource, calSynopticSource WSACalib discrete image classification flag in Y smallint 2 -9999 CLASS_MISC

yClass gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA discrete image classification flag in Y smallint 2 -9999 CLASS_MISC

yClass lasYselJSourceRemeasurement WSA discrete image classification flag in Y smallint 2 -9999 src.class

yClassStat calSource, calSynopticSource WSACalib N(0,1) stellarness-of-profile statistic in Y real 4 -0.9999995e9 STAT_PROP

yClassStat gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA N(0,1) stellarness-of-profile statistic in Y real 4 -0.9999995e9 STAT_PROP

yClassStat lasYselJSourceRemeasurement WSA N(0,1) stellarness-of-profile statistic in Y real 4 -0.9999995e9 stat

ycStratAst calVarFrameSetInfo WSACalib 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.

ycStratPht calVarFrameSetInfo WSACalib 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.

yDeblend calSource WSACalib 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.

yDeblend calSynopticSource WSACalib placeholder flag indicating parent/child relation in Y int 4 -99999999 CODE_MISC

yDeblend gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA placeholder flag indicating parent/child relation in Y int 4 -99999999 CODE_MISC

yDeblend gcsSource, lasSource WSA 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.

ydec StackObjectThin PS1DR2 Declination from y filter stack detection. float 8 degrees -999

ydecErr StackObjectThin PS1DR2 Declination error from y filter stack detection. real 4 arcsec -999

yEll calSource, calSynopticSource WSACalib 1-b/a, where a/b=semi-major/minor axes in Y real 4 -0.9999995e9 PHYS_ELLIPTICITY

yEll gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA 1-b/a, where a/b=semi-major/minor axes in Y real 4 -0.9999995e9 PHYS_ELLIPTICITY

yEll lasYselJSourceRemeasurement WSA 1-b/a, where a/b=semi-major/minor axes in Y real 4 -0.9999995e9 src.ellipticty

yeNum calMergeLog, calSynopticMergeLog WSACalib the extension number of this Y frame tinyint 1 NUMBER

yeNum gcsMergeLog, gcsZYJHKmergeLog, lasMergeLog WSA the extension number of this Y frame tinyint 1 NUMBER

yeNum lasYJHKmergeLog WSA the extension number of this frame tinyint 1 NUMBER

yeNum lasYselJRemeasMergeLog WSA the extension number of this Y frame tinyint 1 meta.number;em.IR.NIR

yEpoch StackObjectThin PS1DR2 Modified Julian Date of the mean epoch of images contributing to the the y-band stack (equinox J2000). float 8 days -999

yErr UKIDSSDetection WSA Error in Y coordinate real 4 pixels ERROR

yErr calDetection WSACalib Error in Y coordinate {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error. real 4 pixels ERROR

yErr dxsDetection, gcsDetection, gpsDetection, lasDetection WSA Error in Y coordinate {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error. real 4 pixels ERROR

yErr lasMapRemeasurement WSA Error in Y coordinate (SE: ERRY2_IMAGE^½) {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error. real 4 pixels stat.error

yErr ptsDetection WSATransit Error in Y coordinate {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error. real 4 pixels ERROR

yErr udsDetection WSA Error in Y coordinate (SE: ERRY2_IMAGE^½) {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error. real 4 pixels ERROR

yErr uhsDetection, uhsDetectionAll WSAUHS Error in Y coordinate {catalogue TType keyword: Y_coordinate_err}
Estimate of centroid error. real 4 pixels ERROR

yErrBits calSource, calSynopticSource WSACalib 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.

yErrBits gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA processing warning/error bitwise flags in Y int 4 -99999999 CODE_MISC

yErrBits gcsSource, lasSource WSA 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.

yErrBits lasYselJSourceRemeasurement WSA processing warning/error bitwise flags in Y int 4 -99999999 meta.code

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 calSource, calSynopticSource WSACalib 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.

yEta gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Offset of Y detection from master position (+north/-south) real 4 arcsec -0.9999995e9 POS_EQ_DEC_OFF

yEta gcsSource, lasSource WSA 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 calVarFrameSetInfo WSACalib 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 calVariability WSACalib 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.

yexpTime StackObjectAttributes PS1DR2 Exposure time of the y filter stack. Necessary for converting listed fluxes and magnitudes back to measured ADU counts. real 4 seconds -999

yExtent RequiredMosaicTopLevel WSAUHS The angular extent of the mosaic image in the y-direction real 4 degrees ??

yExtNSigma StackObjectAttributes PS1DR2 An extendedness measure for the y filter stack detection based on the deviation between PSF and Kron (1980) magnitudes, normalized by the PSF magnitude uncertainty. real 4 -999

yFlags MeanObject PS1DR2 Information flag bitmask for mean object from y filter detections. Values listed in ObjectFilterFlags. int 4 0

yGausig calSource, calSynopticSource WSACalib RMS of axes of ellipse fit in Y real 4 pixels -0.9999995e9 MORPH_PARAM

yGausig gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA RMS of axes of ellipse fit in Y real 4 pixels -0.9999995e9 MORPH_PARAM

yGausig lasYselJSourceRemeasurement WSA RMS of axes of ellipse fit in Y real 4 pixels -0.9999995e9 src.morph.param

yHallMag calSource WSACalib Total point source Y mag real 4 mag -0.9999995e9 PHOT_MAG

yHallMag gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Total point source Y mag real 4 mag -0.9999995e9 PHOT_MAG

yHallMagErr calSource WSACalib Error in total point source Y mag real 4 mag -0.9999995e9 ERROR

yHallMagErr gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error in total point source Y mag real 4 mag -0.9999995e9 ERROR

yinfoFlag StackObjectThin PS1DR2 Information flag bitmask indicating details of the y filter stack photometry. Values listed in DetectionFlags. bigint 8 0

yinfoFlag2 StackObjectThin PS1DR2 Information flag bitmask indicating details of the y filter stack photometry. Values listed in DetectionFlags2. int 4 0

yinfoFlag3 StackObjectThin PS1DR2 Information flag bitmask indicating details of the y filter stack photometry. Values listed in DetectionFlags3. int 4 0

yIntRms calVariability WSACalib 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.

yippDetectID StackObjectAttributes, StackObjectThin PS1DR2 IPP internal detection identifier. bigint 8

yisDefAst calVarFrameSetInfo WSACalib Use a default model for the astrometric noise in Y band. tinyint 1 0

yisDefPht calVarFrameSetInfo WSACalib Use a default model for the photometric noise in Y band. tinyint 1 0

yIsMeas lasYselJSourceRemeasurement WSA Is pass band Y measured? 0 no, 1 yes tinyint 1 0 meta.code

yjiWS calVariability WSACalib 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.

yKronFlux StackObjectAttributes PS1DR2 Kron (1980) flux from y filter stack detection. real 4 Janskys -999

yKronFluxErr StackObjectAttributes PS1DR2 Error in Kron (1980) flux from y filter stack detection. real 4 Janskys -999

yKronMag StackObjectThin PS1DR2 Kron (1980) magnitude from y filter stack detection. real 4 AB magnitudes -999

yKronMagErr StackObjectThin PS1DR2 Error in Kron (1980) magnitude from y filter stack detection. real 4 AB magnitudes -999

yKronRad StackObjectAttributes PS1DR2 Kron (1980) radius from y filter stack detection. real 4 arcsec -999

yMagMAD calVariability WSACalib 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 calVariability WSACalib 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 calVariability WSACalib maximum gap between observations real 4 days -0.9999995e9

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.

yMaxMag calVariability WSACalib 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.

yMeanApMag MeanObject PS1DR2 Mean aperture magnitude from y filter detections. real 4 AB magnitudes -999

yMeanApMagErr MeanObject PS1DR2 Error in mean aperture magnitude from y filter detections. real 4 AB magnitudes -999

yMeanApMagNpt MeanObject PS1DR2 Number of measurements included in mean aperture magnitude from y filter detections. smallint 2 -999

yMeanApMagStd MeanObject PS1DR2 Standard deviation of aperture magnitudes from y filter detections. real 4 AB magnitudes -999

yMeanKronMag MeanObject PS1DR2 Mean Kron (1980) magnitude from y filter detections. real 4 AB magnitudes -999

yMeanKronMagErr MeanObject PS1DR2 Error in mean Kron (1980) magnitude from y filter detections. real 4 AB magnitudes -999

yMeanKronMagNpt MeanObject PS1DR2 Number of measurements included in mean Kron (1980) magnitude from y filter detections. smallint 2 -999

yMeanKronMagStd MeanObject PS1DR2 Standard deviation of Kron (1980) magnitudes from y filter detections. real 4 AB magnitudes -999

ymeanMag calVariability WSACalib 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.

yMeanPSFMag MeanObject PS1DR2 Mean PSF magnitude from y filter detections. real 4 AB magnitudes -999

yMeanPSFMagErr MeanObject PS1DR2 Error in mean PSF magnitude from y filter detections. real 4 AB magnitudes -999

yMeanPSFMagMax MeanObject PS1DR2 Maximum PSF magnitude from y filter detections. real 4 AB magnitudes -999

yMeanPSFMagMin MeanObject PS1DR2 Minimum PSF magnitude from y filter detections. real 4 AB magnitudes -999

yMeanPSFMagNpt MeanObject PS1DR2 Number of measurements included in mean PSF magnitude from y filter detections. smallint 2 -999

yMeanPSFMagStd MeanObject PS1DR2 Standard deviation of PSF magnitudes from y filter detections. real 4 AB magnitudes -999

ymedCadence calVariability WSACalib median gap between observations real 4 days -0.9999995e9

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.

ymedianMag calVariability WSACalib 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 calMergeLog, calSynopticMergeLog WSACalib the UID of the relevant Y multiframe bigint 8 ID_FRAME

ymfID gcsMergeLog, gcsZYJHKmergeLog, lasMergeLog WSA the UID of the relevant Y multiframe bigint 8 ID_FRAME

ymfID lasYJHKmergeLog WSA the UID of the relevant multiframe bigint 8 ID_FRAME

ymfID lasYselJRemeasMergeLog WSA the UID of the relevant Y multiframe bigint 8 meta.id;obs.field;em.IR.NIR

yminCadence calVariability WSACalib minimum gap between observations real 4 days -0.9999995e9

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.

yMinMag calVariability WSACalib 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_1Ext lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Extended source colour Y-J_1 (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR

ymj_1Ext lasSource WSA Extended source colour Y-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.

ymj_1ExtErr lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Error on extended source colour Y-J_1 real 4 mag -0.9999995e9 ERROR

ymj_1ExtErr lasSource WSA Error on extended source colour Y-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.

ymj_1Pnt lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Point source colour Y-J_1 (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR

ymj_1Pnt lasSource WSA Point source colour Y-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.

ymj_1PntErr lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Error on point source colour Y-J_1 real 4 mag -0.9999995e9 ERROR

ymj_1PntErr lasSource WSA Error on point source colour Y-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.

ymj_2Ext lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Extended source colour Y-J_2 (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR

ymj_2Ext lasSource WSA Extended source colour Y-J_2 (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_2ExtErr lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Error on extended source colour Y-J_2 real 4 mag -0.9999995e9 ERROR

ymj_2ExtErr lasSource WSA Error on extended source colour Y-J_2 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_2Pnt lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Point source colour Y-J_2 (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR

ymj_2Pnt lasSource WSA Point source colour Y-J_2 (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_2PntErr lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource WSA Error on point source colour Y-J_2 real 4 mag -0.9999995e9 ERROR

ymj_2PntErr lasSource WSA Error on point source colour Y-J_2 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.

ymjExt calSource WSACalib 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.

ymjExt gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Extended source colour Y-J (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR

ymjExt gcsSource, lasSource WSA 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.

ymjExt lasYselJSourceRemeasurement WSA Extended source colour Y-J (using aperMagNoAperCorr3) 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 calSource WSACalib 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.

ymjExtErr gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error on extended source colour Y-J real 4 mag -0.9999995e9 ERROR

ymjExtErr gcsSource, lasSource WSA 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.

ymjExtErr lasYselJSourceRemeasurement WSA Error on extended source colour Y-J real 4 mag -0.9999995e9 stat.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.

ymjExtJky lasYselJSourceRemeasurement WSA Extended source colour calibrated flux J/Y (using aperJkyNoAperCorr3) real 4 jansky -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.

ymjExtJkyErr lasYselJSourceRemeasurement WSA Error on extended source colour calibrated flux J/Y real 4 jansky -0.9999995e9 stat.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.

ymjExtLup lasYselJSourceRemeasurement WSA Extended source colour luptitudeY-J (using aperLupNoAperCorr3) real 4 lup -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.

ymjExtLupErr lasYselJSourceRemeasurement WSA Error on extended source colour luptitude Y-J real 4 lup -0.9999995e9 stat.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 calSource, calSynopticSource WSACalib 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.

ymjPnt gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Point source colour Y-J (using aperMag3) real 4 mag -0.9999995e9 PHOT_COLOR

ymjPnt gcsSource, lasSource WSA 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.

ymjPnt lasYselJSourceRemeasurement WSA 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 calSource, calSynopticSource WSACalib 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.

ymjPntErr gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error on point source colour Y-J real 4 mag -0.9999995e9 ERROR

ymjPntErr gcsSource, lasSource WSA 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.

ymjPntErr lasYselJSourceRemeasurement WSA Error on point source colour Y-J real 4 mag -0.9999995e9 stat.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.

ymjPntJky lasYselJSourceRemeasurement WSA Point source colour calibrated flux J/Y (using aperJky3) real 4 jansky -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.

ymjPntJkyErr lasYselJSourceRemeasurement WSA Error on point source colour calibrated flux J/Y real 4 jansky -0.9999995e9 stat.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.

ymjPntLup lasYselJSourceRemeasurement WSA Point source colour luptitude Y-J (using aperLup3) real 4 lup -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.

ymjPntLupErr lasYselJSourceRemeasurement WSA Error on point source colour luptitude Y-J real 4 lup -0.9999995e9 stat.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.

ymomentR1 StackObjectAttributes PS1DR2 First radial moment for y filter stack detection. real 4 arcsec -999

ymomentRH StackObjectAttributes PS1DR2 Half radial moment (r^0.5 weighting) for y filter stack detection. real 4 arcsec^0.5 -999

ymomentXX StackObjectAttributes PS1DR2 Second moment M_xx for y filter stack detection. real 4 arcsec^2 -999

ymomentXY StackObjectAttributes PS1DR2 Second moment M_xy for y filter stack detection. real 4 arcsec^2 -999

ymomentYY StackObjectAttributes PS1DR2 Second moment M_yy for y filter stack detection. real 4 arcsec^2 -999

yndof calVariability WSACalib Number of degrees of freedom for chisquare smallint 2 -9999

The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.

ynDofAst calVarFrameSetInfo WSACalib 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.

ynDofPht calVarFrameSetInfo WSACalib 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 calVariability WSACalib 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.

ynFrames StackObjectThin PS1DR2 Number of input frames/exposures contributing to the y filter stack detection. int 4 -999

ynGoodObs calVariability WSACalib 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 calVariability WSACalib 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.

ynMissingObs calVariability WSACalib 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.

yOverlap RequiredMosaicTopLevel WSAUHS The overlap between adjacent mosaics in the y-direction real 4 degrees ??

yPA calSource, calSynopticSource WSACalib ellipse fit celestial orientation in Y real 4 Degrees -0.9999995e9 POS_POS-ANG

yPA gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA ellipse fit celestial orientation in Y real 4 Degrees -0.9999995e9 POS_POS-ANG

yPA lasYselJSourceRemeasurement WSA ellipse fit celestial orientation in Y real 4 Degrees -0.9999995e9 pos.posAng

yPetroMag calSource WSACalib Extended source Y mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG

yPetroMag gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Extended source Y mag (Petrosian) real 4 mag -0.9999995e9 PHOT_MAG

yPetroMagErr calSource WSACalib Error in extended source Y mag (Petrosian) real 4 mag -0.9999995e9 ERROR

yPetroMagErr gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error in extended source Y mag (Petrosian) real 4 mag -0.9999995e9 ERROR

yPixSize CurrentAstrometry WSACalib Angular size of pixels in Y real 4 Arcseconds -0.9999995e9 pos.angDistance

yPixSize CurrentAstrometry WSATransit Angular size of pixels in Y real 4 Arcseconds -0.9999995e9 pos.angDistance

yPixSize CurrentAstrometry WSAUHS Angular size of pixels in Y real 4 Arcseconds -0.9999995e9 pos.angDistance

yPixSize CurrentAstrometry, PreviousAstrometry WSA Angular size of pixels in Y real 4 Arcseconds -0.9999995e9 pos.angDistance

yPlateScale StackObjectAttributes PS1DR2 Local plate scale for the y filter stack. real 4 arcsec/pixel 0

yPos Detection PS1DR2 PSF y center location. real 4 raw pixels -999

yPos nvssSource NVSS Y position (Dec direction) of the radio source real 4 pixels POS_CCD_Y

yPosErr Detection PS1DR2 Error in PSF y center location. real 4 raw pixels -999

yppErrBits calSource, calSynopticSource WSACalib 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.

yppErrBits gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA additional WFAU post-processing error bits in Y int 4 0 CODE_MISC

yppErrBits gcsSource, lasSource WSA 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.

yppErrBits lasYselJSourceRemeasurement WSA additional WFAU post-processing error bits in Y int 4 0 meta.code

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 calVariability WSACalib Probability of variable from chi-square (and other data) real 4 -0.9999995e9

The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.

ypsfChiSq StackObjectAttributes PS1DR2 Reduced chi squared value of the PSF model fit for y filter stack detection. real 4 -999

ypsfCore StackObjectAttributes PS1DR2 PSF core parameter k from y filter stack detection, where F = F0 / (1 + k r^2 + r^3.33). real 4 -999

yPSFFlux StackObjectAttributes PS1DR2 PSF flux from y filter stack detection. real 4 Janskys -999

yPSFFluxErr StackObjectAttributes PS1DR2 Error in PSF flux from y filter stack detection. real 4 Janskys -999

ypsfLikelihood StackObjectAttributes PS1DR2 Likelihood that this y filter stack detection is best fit by a PSF. real 4 -999

yPSFMag StackObjectThin PS1DR2 PSF magnitude from y filter stack detection. real 4 AB magnitudes -999

yPsfMag calSource WSACalib Point source profile-fitted Y mag real 4 mag -0.9999995e9 PHOT_MAG

yPsfMag gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Point source profile-fitted Y mag real 4 mag -0.9999995e9 PHOT_MAG

yPSFMagErr StackObjectThin PS1DR2 Error in PSF magnitude from y filter stack detection. real 4 AB magnitudes -999

yPsfMagErr calSource WSACalib Error in point source profile-fitted Y mag real 4 mag -0.9999995e9 ERROR

yPsfMagErr gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error in point source profile-fitted Y mag real 4 mag -0.9999995e9 ERROR

ypsfMajorFWHM StackObjectAttributes PS1DR2 PSF major axis FWHM from y filter stack detection. real 4 arcsec -999

ypsfMinorFWHM StackObjectAttributes PS1DR2 PSF minor axis FWHM from y filter stack detection. real 4 arcsec -999

ypsfQf StackObjectAttributes PS1DR2 PSF coverage factor for y filter stack detection. real 4 -999

ypsfQfPerfect StackObjectAttributes PS1DR2 PSF-weighted fraction of pixels totally unmasked for y filter stack detection. real 4 -999

ypsfTheta StackObjectAttributes PS1DR2 PSF major axis orientation from y filter stack detection. real 4 degrees -999

yQfPerfect MeanObject PS1DR2 Maximum PSF weighted fraction of pixels totally unmasked from y filter detections. real 4 -999

yra StackObjectThin PS1DR2 Right ascension from y filter stack detection. float 8 degrees -999

yraErr StackObjectThin PS1DR2 Right ascension error from y filter stack detection. real 4 arcsec -999

ySeqNum calSource, calSynopticSource WSACalib the running number of the Y detection int 4 -99999999 ID_NUMBER

ySeqNum gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA the running number of the Y detection int 4 -99999999 ID_NUMBER

ySerMag2D calSource WSACalib Extended source Y mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG

ySerMag2D gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Extended source Y mag (profile-fitted) real 4 mag -0.9999995e9 PHOT_MAG

ySerMag2DErr calSource WSACalib Error in extended source Y mag (profile-fitted) real 4 mag -0.9999995e9 ERROR

ySerMag2DErr gcsPointSource, gcsSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Error in extended source Y mag (profile-fitted) real 4 mag -0.9999995e9 ERROR

ySize MultiframeDetector WSA Corresponding image size (Y); value only available if catalogue file exists {catalogue extension keyword: NYOUT} int 4 -99999999 meta.number

ySize MultiframeDetector WSACalib Corresponding image size (Y); value only available if catalogue file exists {catalogue extension keyword: NYOUT} int 4 -99999999 meta.number

ySize MultiframeDetector WSATransit Corresponding image size (Y); value only available if catalogue file exists {catalogue extension keyword: NYOUT} int 4 -99999999 meta.number

ySize MultiframeDetector WSAUHS Corresponding image size (Y); value only available if catalogue file exists {catalogue extension keyword: NYOUT} int 4 -99999999 meta.number

yskewness calVariability WSACalib 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.

ysky StackObjectAttributes PS1DR2 Residual background sky level at the y filter stack detection. real 4 Janskys/arcsec^2 -999

yskyErr StackObjectAttributes PS1DR2 Error in residual background sky level at the y filter stack detection. real 4 Janskys/arcsec^2 -999

ystackDetectID StackObjectAttributes, StackObjectThin PS1DR2 Unique stack detection identifier. bigint 8

ystackImageID StackObjectAttributes, StackObjectThin PS1DR2 Unique stack identifier for y filter detection. bigint 8

ytotalPeriod calVariability WSACalib total period of observations (last obs-first obs) real 4 days -0.9999995e9

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable.

yVarClass calVariability WSACalib Classification of variability in this band smallint 2 -9999

The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chi-squared is calculated, assuming a non-variable object which has the noise from the expected-rms and mean calculated as above. The probVar statistic assumes a chi-squared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3.

yXi calSource, calSynopticSource WSACalib 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.

yXi gcsPointSource, gcsZYJHKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableGcsPointSource, reliableLasPointSource WSA Offset of Y detection from master position (+east/-west) real 4 arcsec -0.9999995e9 POS_EQ_RA_OFF

yXi gcsSource, lasSource WSA 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.

yxPos StackObjectAttributes PS1DR2 PSF x center location from y filter stack detection. real 4 sky pixels -999

yxPosErr StackObjectAttributes PS1DR2 Error in PSF x center location from y filter stack detection. real 4 sky pixels -999

yyPos StackObjectAttributes PS1DR2 PSF y center location from y filter stack detection. real 4 sky pixels -999

yyPosErr StackObjectAttributes PS1DR2 Error in PSF y center location from y filter stack detection. real 4 sky pixels -999

yzp StackObjectAttributes PS1DR2 Photometric zeropoint for the y filter stack. Necessary for converting listed fluxes and magnitudes back to measured ADU counts. real 4 magnitudes 0

WFAU, Institute for Astronomy,
Royal Observatory, Blackford Hill
Edinburgh, EH9 3HJ, UK

wsa-support@roe.ac.uk
17/01/2022