K 
Name  Schema Table  Database  Description  Type  Length  Unit  Default Value  Unified Content Descriptor 
k_1AperMag1 
gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource 
WSA 
Extended source 1st epoch K aperture corrected mag (1.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1AperMag1Err 
gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource 
WSA 
Error in extended source 1st epoch K mag (1.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1AperMag3 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Default point/extended source 1st epoch K aperture corrected mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1AperMag3 
gcsSource, gpsSource 
WSA 
Default point/extended source 1st epoch K aperture corrected mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1AperMag3Err 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Error in default point/extended source 1st epoch K mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1AperMag4 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Extended source 1st epoch K aperture corrected mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1AperMag4Err 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Error in extended source 1st epoch K mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1AperMag6 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Extended source 1st epoch K aperture corrected mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1AperMag6Err 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in extended source 1st epoch K mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1Class 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
discrete image classification flag in 1st epoch K 
smallint 
2 

9999 
CLASS_MISC 
k_1ClassStat 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsSourceRemeasurement, reliableGcsPointSource 
WSA 
N(0,1) stellarnessofprofile statistic in 1st epoch K 
real 
4 

0.9999995e9 
STAT_PROP 
k_1ClassStat 
gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource 
WSA 
SExtractor classification statistic in 1st epoch K 
real 
4 

0.9999995e9 
STAT_PROP 
k_1Deblend 
gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
placeholder flag indicating parent/child relation in 1st epoch K 
int 
4 

99999999 
CODE_MISC 
k_1Deblend 
gcsSource 
WSA 
placeholder flag indicating parent/child relation in 1st epoch K 
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 postprocessing software based on testing the areal profiles aprof28 (these are set by CASU to 1 for deblended components, or positive values for nondeblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables. 
k_1Ell 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
1b/a, where a/b=semimajor/minor axes in 1st epoch K 
real 
4 

0.9999995e9 
PHYS_ELLIPTICITY 
k_1eNum 
gcsMergeLog, gcsZYJHKmergeLog, gpsJHKmergeLog, gpsMergeLog 
WSA 
the extension number of this 1st epoch K frame 
tinyint 
1 


NUMBER 
k_1ErrBits 
gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
processing warning/error bitwise flags in 1st epoch K 
int 
4 

99999999 
CODE_MISC 
k_1ErrBits 
gcsSource 
WSA 
processing warning/error bitwise flags in 1st epoch K 
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. 
k_1ErrBits 
gpsSource 
WSA 
processing warning/error bitwise flags in 1st epoch K 
int 
4 

99999999 
CODE_MISC 
This uses the FLAGS attribute in SE. The individual bit flags that this can be decomposed into are as follows: Bit Flag  Meaning   1  The object has neighbours, bright enough and close enough to significantly bias the MAG_AUTO photometry or bad pixels (more than 10% of photometry affected).   2  The object was originally blended with another   4  At least one pixel is saturated (or very close to)   8  The object is truncated (too close to an image boundary)   16  Object's aperture data are incomplete or corrupted   32  Object's isophotal data are imcomplete or corrupted. This is an old flag inherited from SE v1.0, and is kept for compatability reasons. It doesn't have any consequence for the extracted parameters.   64  Memory overflow occurred during deblending   128  Memory overflow occurred during extraction  

k_1Eta 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Offset of 1st epoch K detection from master position (+north/south) 
real 
4 
arcsec 
0.9999995e9 
POS_EQ_DEC_OFF 
k_1Eta 
gcsSource, gpsSource 
WSA 
Offset of 1st epoch K 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 nonsurvey 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. 
k_1Gausig 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
RMS of axes of ellipse fit in 1st epoch K 
real 
4 
pixels 
0.9999995e9 
MORPH_PARAM 
k_1HallMag 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Total point source 1st epoch K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1HallMagErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in total point source 1st epoch K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1Mag 
gcsSourceRemeasurement, gpsSourceRemeasurement 
WSA 
1st epoch K mag (as appropriate for this merged source) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1MagErr 
gcsSourceRemeasurement, gpsSourceRemeasurement 
WSA 
Error in 1st epoch K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1mfID 
gcsMergeLog, gcsZYJHKmergeLog, gpsJHKmergeLog, gpsMergeLog 
WSA 
the UID of the relevant 1st epoch K multiframe 
bigint 
8 


ID_FRAME 
k_1ObjID 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
DEPRECATED (do not use) 
bigint 
8 

99999999 
ID_NUMBER 
k_1ObjID 
gcsSource, gcsSourceRemeasurement, gpsSource, gpsSourceRemeasurement 
WSA 
DEPRECATED (do not use) 
bigint 
8 

99999999 
ID_NUMBER 
This attribute is included in source tables for historical reasons, but it's use is not recommended unless you really know what you are doing. In general, if you need to look up detection table attributes for a source in a given passband that are not in the source table, you should make an SQL join between source, mergelog and detection using the primary key attribute frameSetID and combination multiframeID, extNum, seqNum to associate related rows between the three tables. See the Q&A example SQL for more information. 
k_1PA 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
ellipse fit celestial orientation in 1st epoch K 
real 
4 
Degrees 
0.9999995e9 
POS_POSANG 
k_1PetroMag 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Extended source 1st epoch K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1PetroMagErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in extended source 1st epoch K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1ppErrBits 
gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
additional WFAU postprocessing error bits in 1st epoch K 
int 
4 

0 
CODE_MISC 
k_1ppErrBits 
gcsSource 
WSA 
additional WFAU postprocessing error bits in 1st epoch K 
int 
4 

0 
CODE_MISC 
Postprocessing 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 4byte 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. 
k_1PsfMag 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Point source profilefitted 1st epoch K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1PsfMagErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in point source profilefitted 1st epoch K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1SeqNum 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
the running number of the 1st epoch K detection 
int 
4 

99999999 
ID_NUMBER 
k_1SeqNum 
gcsSourceRemeasurement, gpsSourceRemeasurement 
WSA 
the running number of the 1st epoch K remeasurement 
int 
4 

99999999 
ID_NUMBER 
k_1SerMag2D 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Extended source 1st epoch K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_1SerMag2DErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in extended source 1st epoch K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_1Xi 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Offset of 1st epoch K detection from master position (+east/west) 
real 
4 
arcsec 
0.9999995e9 
POS_EQ_RA_OFF 
k_1Xi 
gcsSource, gpsSource 
WSA 
Offset of 1st epoch K 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 nonsurvey 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. 
k_2AperMag1 
gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource 
WSA 
Extended source 2nd epoch K aperture corrected mag (1.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2AperMag1Err 
gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource 
WSA 
Error in extended source 2nd epoch K mag (1.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2AperMag3 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Default point/extended source 2nd epoch K aperture corrected mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2AperMag3 
gcsSource, gpsSource 
WSA 
Default point/extended source 2nd epoch K aperture corrected mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2AperMag3Err 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Error in default point/extended source 2nd epoch K mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2AperMag4 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Extended source 2nd epoch K aperture corrected mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2AperMag4Err 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Error in extended source 2nd epoch K mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2AperMag6 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Extended source 2nd epoch K aperture corrected mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2AperMag6Err 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in extended source 2nd epoch K mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2Class 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
discrete image classification flag in 2nd epoch K 
smallint 
2 

9999 
CLASS_MISC 
k_2ClassStat 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsSourceRemeasurement, reliableGcsPointSource 
WSA 
N(0,1) stellarnessofprofile statistic in 2nd epoch K 
real 
4 

0.9999995e9 
STAT_PROP 
k_2ClassStat 
gpsJHKsource, gpsPointSource, gpsSource, reliableGpsPointSource 
WSA 
SExtractor classification statistic in 2nd epoch K 
real 
4 

0.9999995e9 
STAT_PROP 
k_2Deblend 
gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
placeholder flag indicating parent/child relation in 2nd epoch K 
int 
4 

99999999 
CODE_MISC 
k_2Deblend 
gcsSource 
WSA 
placeholder flag indicating parent/child relation in 2nd epoch K 
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 postprocessing software based on testing the areal profiles aprof28 (these are set by CASU to 1 for deblended components, or positive values for nondeblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables. 
k_2Ell 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
1b/a, where a/b=semimajor/minor axes in 2nd epoch K 
real 
4 

0.9999995e9 
PHYS_ELLIPTICITY 
k_2eNum 
gcsMergeLog, gcsZYJHKmergeLog, gpsJHKmergeLog, gpsMergeLog 
WSA 
the extension number of this 2nd epoch K frame 
tinyint 
1 


NUMBER 
k_2ErrBits 
gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
processing warning/error bitwise flags in 2nd epoch K 
int 
4 

99999999 
CODE_MISC 
k_2ErrBits 
gcsSource 
WSA 
processing warning/error bitwise flags in 2nd epoch K 
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. 
k_2ErrBits 
gpsSource 
WSA 
processing warning/error bitwise flags in 2nd epoch K 
int 
4 

99999999 
CODE_MISC 
This uses the FLAGS attribute in SE. The individual bit flags that this can be decomposed into are as follows: Bit Flag  Meaning   1  The object has neighbours, bright enough and close enough to significantly bias the MAG_AUTO photometry or bad pixels (more than 10% of photometry affected).   2  The object was originally blended with another   4  At least one pixel is saturated (or very close to)   8  The object is truncated (too close to an image boundary)   16  Object's aperture data are incomplete or corrupted   32  Object's isophotal data are imcomplete or corrupted. This is an old flag inherited from SE v1.0, and is kept for compatability reasons. It doesn't have any consequence for the extracted parameters.   64  Memory overflow occurred during deblending   128  Memory overflow occurred during extraction  

k_2Eta 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Offset of 2nd epoch K detection from master position (+north/south) 
real 
4 
arcsec 
0.9999995e9 
POS_EQ_DEC_OFF 
k_2Eta 
gcsSource, gpsSource 
WSA 
Offset of 2nd epoch K 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 nonsurvey 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. 
k_2Gausig 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
RMS of axes of ellipse fit in 2nd epoch K 
real 
4 
pixels 
0.9999995e9 
MORPH_PARAM 
k_2HallMag 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Total point source 2nd epoch K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2HallMagErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in total point source 2nd epoch K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2Mag 
gcsSourceRemeasurement, gpsSourceRemeasurement 
WSA 
2nd epoch K mag (as appropriate for this merged source) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2MagErr 
gcsSourceRemeasurement, gpsSourceRemeasurement 
WSA 
Error in 2nd epoch K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2mfID 
gcsMergeLog, gcsZYJHKmergeLog, gpsJHKmergeLog, gpsMergeLog 
WSA 
the UID of the relevant 2nd epoch K multiframe 
bigint 
8 


ID_FRAME 
k_2mrat 
twomass_scn 
2MASS 
Ksband average 2nd image moment ratio. 
real 
4 


FIT_PARAM_VALUE 
k_2mrat 
twomass_sixx2_scn 
2MASS 
K band average 2nd image moment ratio for scan 
real 
4 



k_2ObjID 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
DEPRECATED (do not use) 
bigint 
8 

99999999 
ID_NUMBER 
k_2ObjID 
gcsSource, gcsSourceRemeasurement, gpsSource, gpsSourceRemeasurement 
WSA 
DEPRECATED (do not use) 
bigint 
8 

99999999 
ID_NUMBER 
This attribute is included in source tables for historical reasons, but it's use is not recommended unless you really know what you are doing. In general, if you need to look up detection table attributes for a source in a given passband that are not in the source table, you should make an SQL join between source, mergelog and detection using the primary key attribute frameSetID and combination multiframeID, extNum, seqNum to associate related rows between the three tables. See the Q&A example SQL for more information. 
k_2PA 
gcsPointSource, gcsSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
ellipse fit celestial orientation in 2nd epoch K 
real 
4 
Degrees 
0.9999995e9 
POS_POSANG 
k_2PetroMag 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Extended source 2nd epoch K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2PetroMagErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in extended source 2nd epoch K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2ppErrBits 
gcsPointSource, gcsSourceRemeasurement, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, gpsSourceRemeasurement, reliableGcsPointSource, reliableGpsPointSource 
WSA 
additional WFAU postprocessing error bits in 2nd epoch K 
int 
4 

0 
CODE_MISC 
k_2ppErrBits 
gcsSource 
WSA 
additional WFAU postprocessing error bits in 2nd epoch K 
int 
4 

0 
CODE_MISC 
Postprocessing 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 4byte 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. 
k_2PsfMag 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Point source profilefitted 2nd epoch K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2PsfMagErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in point source profilefitted 2nd epoch K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2SeqNum 
gcsPointSource, gcsSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, gpsSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
the running number of the 2nd epoch K detection 
int 
4 

99999999 
ID_NUMBER 
k_2SeqNum 
gcsSourceRemeasurement, gpsSourceRemeasurement 
WSA 
the running number of the 2nd epoch K remeasurement 
int 
4 

99999999 
ID_NUMBER 
k_2SerMag2D 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Extended source 2nd epoch K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
k_2SerMag2DErr 
gcsPointSource, gcsSource, gcsZYJHKsource, reliableGcsPointSource 
WSA 
Error in extended source 2nd epoch K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
ERROR 
k_2Xi 
gcsPointSource, gcsZYJHKsource, gpsJHKsource, gpsPointSource, reliableGcsPointSource, reliableGpsPointSource 
WSA 
Offset of 2nd epoch K detection from master position (+east/west) 
real 
4 
arcsec 
0.9999995e9 
POS_EQ_RA_OFF 
k_2Xi 
gcsSource, gpsSource 
WSA 
Offset of 2nd epoch K 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 nonsurvey 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. 
k_5sig_ba 
twomass_xsc 
2MASS 
K minor/major axis ratio fit to the 5sigma isophote. 
real 
4 


PHYS_AXISRATIO 
k_5sig_phi 
twomass_xsc 
2MASS 
K angle to 5sigma major axis (E of N). 
smallint 
2 
degrees 

ERROR 
k_5surf 
twomass_xsc 
2MASS 
K central surface brightness (r<=5). 
real 
4 
mag 

PHOT_SB_GENERAL 
k_ba 
twomass_sixx2_xsc 
2MASS 
K minor/major axis ratio fit to the 3sigma isophote 
real 
4 



k_ba 
twomass_xsc 
2MASS 
K minor/major axis ratio fit to the 3sigma isophote. 
real 
4 


PHYS_AXISRATIO 
k_back 
twomass_xsc 
2MASS 
K coadd median background. 
real 
4 


CODE_MISC 
k_bisym_chi 
twomass_xsc 
2MASS 
K bisymmetric crosscorrelation chi. 
real 
4 


FIT_PARAM_VALUE 
k_bisym_rat 
twomass_xsc 
2MASS 
K bisymmetric flux ratio. 
real 
4 


PHOT_FLUX_RATIO 
k_bndg_amp 
twomass_xsc 
2MASS 
K banding maximum FT amplitude on this side of coadd. 
real 
4 
DN 

FIT_PARAM_VALUE 
k_bndg_per 
twomass_xsc 
2MASS 
K banding Fourier Transf. period on this side of coadd. 
int 
4 
arcsec 

FIT_PARAM_VALUE 
k_chif_ellf 
twomass_xsc 
2MASS 
K % chifraction for elliptical fit to 3sig isophote. 
real 
4 


FIT_PARAM_VALUE 
k_cmsig 
twomass_psc 
2MASS 
Corrected photometric uncertainty for the default Ksband magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_con_indx 
twomass_xsc 
2MASS 
K concentration index r_75%/r_25%. 
real 
4 


PHYS_CONCENT_INDEX 
k_d_area 
twomass_xsc 
2MASS 
K 5sigma to 3sigma differential area. 
smallint 
2 


FIT_RESIDUAL 
k_flg_10 
twomass_xsc 
2MASS 
K confusion flag for 10 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_15 
twomass_xsc 
2MASS 
K confusion flag for 15 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_20 
twomass_xsc 
2MASS 
K confusion flag for 20 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_25 
twomass_xsc 
2MASS 
K confusion flag for 25 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_30 
twomass_xsc 
2MASS 
K confusion flag for 30 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_40 
twomass_xsc 
2MASS 
K confusion flag for 40 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_5 
twomass_xsc 
2MASS 
K confusion flag for 5 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_50 
twomass_xsc 
2MASS 
K confusion flag for 50 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_60 
twomass_xsc 
2MASS 
K confusion flag for 60 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_7 
twomass_sixx2_xsc 
2MASS 
K confusion flag for 7 arcsec circular ap. mag 
smallint 
2 



k_flg_7 
twomass_xsc 
2MASS 
K confusion flag for 7 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_70 
twomass_xsc 
2MASS 
K confusion flag for 70 arcsec circular ap. mag. 
smallint 
2 


CODE_MISC 
k_flg_c 
twomass_xsc 
2MASS 
K confusion flag for Kron circular mag. 
smallint 
2 


CODE_MISC 
k_flg_e 
twomass_xsc 
2MASS 
K confusion flag for Kron elliptical mag. 
smallint 
2 


CODE_MISC 
k_flg_fc 
twomass_xsc 
2MASS 
K confusion flag for fiducial Kron circ. mag. 
smallint 
2 


CODE_MISC 
k_flg_fe 
twomass_xsc 
2MASS 
K confusion flag for fiducial Kron ell. mag. 
smallint 
2 


CODE_MISC 
k_flg_i20c 
twomass_xsc 
2MASS 
K confusion flag for 20mag/sq." iso. circ. mag. 
smallint 
2 


CODE_MISC 
k_flg_i20e 
twomass_xsc 
2MASS 
K confusion flag for 20mag/sq." iso. ell. mag. 
smallint 
2 


CODE_MISC 
k_flg_i21c 
twomass_xsc 
2MASS 
K confusion flag for 21mag/sq." iso. circ. mag. 
smallint 
2 


CODE_MISC 
k_flg_i21e 
twomass_xsc 
2MASS 
K confusion flag for 21mag/sq." iso. ell. mag. 
smallint 
2 


CODE_MISC 
k_flg_j21fc 
twomass_xsc 
2MASS 
K confusion flag for 21mag/sq." iso. fid. circ. mag. 
smallint 
2 


CODE_MISC 
k_flg_j21fe 
twomass_xsc 
2MASS 
K confusion flag for 21mag/sq." iso. fid. ell. mag. 
smallint 
2 


CODE_MISC 
k_flg_k20fc 
twomass_xsc 
2MASS 
K confusion flag for 20mag/sq." iso. fid. circ. mag. 
smallint 
2 


CODE_MISC 
k_flg_k20fe 
twomass_sixx2_xsc 
2MASS 
K confusion flag for 20mag/sq.″ iso. fid. ell. mag 
smallint 
2 



k_flg_k20fe 
twomass_xsc 
2MASS 
K confusion flag for 20mag/sq." iso. fid. ell. mag. 
smallint 
2 


CODE_MISC 
k_m 
twomass_psc 
2MASS 
Default Ksband magnitude 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m 
twomass_sixx2_psc 
2MASS 
K selected "default" magnitude 
real 
4 
mag 


k_m_10 
twomass_xsc 
2MASS 
K 10 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_15 
twomass_xsc 
2MASS 
K 15 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_20 
twomass_xsc 
2MASS 
K 20 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_25 
twomass_xsc 
2MASS 
K 25 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_2mass 
allwise_sc2 
WISE 
2MASS K_{s}band magnitude of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC K_{s}band magnitude entry is "null". 
float 
8 
mag 


k_m_30 
twomass_xsc 
2MASS 
K 30 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_40 
twomass_xsc 
2MASS 
K 40 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_5 
twomass_xsc 
2MASS 
K 5 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_50 
twomass_xsc 
2MASS 
K 50 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_60 
twomass_xsc 
2MASS 
K 60 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_7 
twomass_sixx2_xsc 
2MASS 
K 7 arcsec radius circular aperture magnitude 
real 
4 
mag 


k_m_7 
twomass_xsc 
2MASS 
K 7 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_70 
twomass_xsc 
2MASS 
K 70 arcsec radius circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_c 
twomass_xsc 
2MASS 
K Kron circular aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_e 
twomass_xsc 
2MASS 
K Kron elliptical aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_ext 
twomass_sixx2_xsc 
2MASS 
K mag from fit extrapolation 
real 
4 
mag 


k_m_ext 
twomass_xsc 
2MASS 
K mag from fit extrapolation. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_fc 
twomass_xsc 
2MASS 
K fiducial Kron circular magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_fe 
twomass_xsc 
2MASS 
K fiducial Kron ell. mag aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_i20c 
twomass_xsc 
2MASS 
K 20mag/sq." isophotal circular ap. magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_i20e 
twomass_xsc 
2MASS 
K 20mag/sq." isophotal elliptical ap. magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_i21c 
twomass_xsc 
2MASS 
K 21mag/sq." isophotal circular ap. magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_i21e 
twomass_xsc 
2MASS 
K 21mag/sq." isophotal elliptical ap. magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_j21fc 
twomass_xsc 
2MASS 
K 21mag/sq." isophotal fiducial circ. ap. mag. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_j21fe 
twomass_xsc 
2MASS 
K 21mag/sq." isophotal fiducial ell. ap. magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_k20fc 
twomass_xsc 
2MASS 
K 20mag/sq." isophotal fiducial circ. ap. mag. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_k20fe 
twomass_sixx2_xsc 
2MASS 
K 20mag/sq.″ isophotal fiducial ell. ap. magnitude 
real 
4 
mag 


k_m_k20fe 
twomass_xsc 
2MASS 
K 20mag/sq." isophotal fiducial ell. ap. magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_stdap 
twomass_psc 
2MASS 
Ksband "standard" aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_m_sys 
twomass_xsc 
2MASS 
K system photometry magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_mnsurfb_eff 
twomass_xsc 
2MASS 
K mean surface brightness at the halflight radius. 
real 
4 
mag 

PHOT_SB_GENERAL 
k_msig 
twomass_sixx2_psc 
2MASS 
K "default" mag uncertainty 
real 
4 
mag 


k_msig_10 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 10 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_15 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 15 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_20 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 20 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_25 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 25 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_2mass 
allwise_sc2 
WISE 
2MASS K_{s}band corrected photometric uncertainty of the associated 2MASS PSC source. This column is "null" if there is no associated 2MASS PSC source or if the 2MASS PSC K_{s}band uncertainty entry is "null". 
float 
8 
mag 


k_msig_30 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 30 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_40 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 40 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_5 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 5 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_50 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 50 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_60 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 60 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_7 
twomass_sixx2_xsc 
2MASS 
K 1sigma uncertainty in 7 arcsec circular ap. mag 
real 
4 
mag 


k_msig_7 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 7 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_70 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 70 arcsec circular ap. mag. 
real 
4 
mag 

ERROR 
k_msig_c 
twomass_xsc 
2MASS 
K 1sigma uncertainty in Kron circular mag. 
real 
4 
mag 

ERROR 
k_msig_e 
twomass_xsc 
2MASS 
K 1sigma uncertainty in Kron elliptical mag. 
real 
4 
mag 

ERROR 
k_msig_ext 
twomass_sixx2_xsc 
2MASS 
K 1sigma uncertainty in mag from fit extrapolation 
real 
4 
mag 


k_msig_ext 
twomass_xsc 
2MASS 
K 1sigma uncertainty in mag from fit extrapolation. 
real 
4 
mag 

ERROR 
k_msig_fc 
twomass_xsc 
2MASS 
K 1sigma uncertainty in fiducial Kron circ. mag. 
real 
4 
mag 

ERROR 
k_msig_fe 
twomass_xsc 
2MASS 
K 1sigma uncertainty in fiducial Kron ell. mag. 
real 
4 
mag 

ERROR 
k_msig_i20c 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 20mag/sq." iso. circ. mag. 
real 
4 
mag 

ERROR 
k_msig_i20e 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 20mag/sq." iso. ell. mag. 
real 
4 
mag 

ERROR 
k_msig_i21c 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 21mag/sq." iso. circ. mag. 
real 
4 
mag 

ERROR 
k_msig_i21e 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 21mag/sq." iso. ell. mag. 
real 
4 
mag 

ERROR 
k_msig_j21fc 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 21mag/sq." iso.fid.circ.mag. 
real 
4 
mag 

ERROR 
k_msig_j21fe 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 21mag/sq." iso.fid.ell.mag. 
real 
4 
mag 

ERROR 
k_msig_k20fc 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 20mag/sq." iso.fid.circ. mag. 
real 
4 
mag 

ERROR 
k_msig_k20fe 
twomass_sixx2_xsc 
2MASS 
K 1sigma uncertainty in 20mag/sq.″ iso.fid.ell.mag 
real 
4 
mag 


k_msig_k20fe 
twomass_xsc 
2MASS 
K 1sigma uncertainty in 20mag/sq." iso.fid.ell.mag. 
real 
4 
mag 

ERROR 
k_msig_stdap 
twomass_psc 
2MASS 
Uncertainty in the Ksband standard aperture magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_msig_sys 
twomass_xsc 
2MASS 
K 1sigma uncertainty in system photometry mag. 
real 
4 
mag 

ERROR 
k_msigcom 
twomass_psc 
2MASS 
Combined, or total photometric uncertainty for the default Ksband magnitude. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_msigcom 
twomass_sixx2_psc 
2MASS 
combined (total) K band photometric uncertainty 
real 
4 
mag 


k_msnr10 
twomass_scn 
2MASS 
The estimated Ksband magnitude at which SNR=10 is achieved for this scan. 
real 
4 
mag 

SPECT_FLUX_VALUE 
k_msnr10 
twomass_sixx2_scn 
2MASS 
K mag at which SNR=10 is achieved, from k_psp and k_zp_ap 
real 
4 
mag 


k_n_snr10 
twomass_scn 
2MASS 
Number of point sources at Ksband with SNR>10 (instrumental mag <=14.3) 
int 
4 


NUMBER 
k_n_snr10 
twomass_sixx2_scn 
2MASS 
number of K point sources with SNR>10 (instrumental m<=14.3) 
int 
4 



k_pchi 
twomass_xsc 
2MASS 
K chi^2 of fit to rad. profile (LCSB: alpha scale len). 
real 
4 


FIT_PARAM_VALUE 
k_peak 
twomass_xsc 
2MASS 
K peak pixel brightness. 
real 
4 
mag 

PHOT_SB_GENERAL 
k_perc_darea 
twomass_xsc 
2MASS 
K 5sigma to 3sigma percent area change. 
smallint 
2 


FIT_PARAM 
k_phi 
twomass_sixx2_xsc 
2MASS 
K angle to 3sigma major axis (E of N) 
smallint 
2 
deg 


k_phi 
twomass_xsc 
2MASS 
K angle to 3sigma major axis (E of N). 
smallint 
2 
degrees 

POS_POSANG 
k_psfchi 
twomass_psc 
2MASS 
Reduced chisquared goodnessoffit value for the Ksband profilefit photometry made on the 1.3 s "Read_2" exposures. 
real 
4 


FIT_PARAM_VALUE 
k_psp 
twomass_scn 
2MASS 
Ksband photometric sensitivity paramater (PSP). 
real 
4 


INST_SENSITIVITY 
k_psp 
twomass_sixx2_scn 
2MASS 
K photometric sensitivity param: k_shape_avg*(k_fbg_avg^.29) 
real 
4 



k_pts_noise 
twomass_scn 
2MASS 
Base10 logarithm of the mode of the noise distribution for all point source detections in the scan, where the noise is estimated from the measured Ksband photometric errors and is expressed in units of mJy. 
real 
4 


INST_NOISE 
k_pts_noise 
twomass_sixx2_scn 
2MASS 
log10 of K band modal point src noise estimate 
real 
4 
logmJy 


k_r_c 
twomass_xsc 
2MASS 
K Kron circular aperture radius. 
real 
4 
arcsec 

EXTENSION_RAD 
k_r_e 
twomass_xsc 
2MASS 
K Kron elliptical aperture semimajor axis. 
real 
4 
arcsec 

EXTENSION_RAD 
k_r_eff 
twomass_xsc 
2MASS 
K halflight (integrated halfflux point) radius. 
real 
4 
arcsec 

EXTENSION_RAD 
k_r_i20c 
twomass_xsc 
2MASS 
K 20mag/sq." isophotal circular aperture radius. 
real 
4 
arcsec 

EXTENSION_RAD 
k_r_i20e 
twomass_xsc 
2MASS 
K 20mag/sq." isophotal elliptical ap. semimajor axis. 
real 
4 
arcsec 

EXTENSION_RAD 
k_r_i21c 
twomass_xsc 
2MASS 
K 21mag/sq." isophotal circular aperture radius. 
real 
4 
arcsec 

EXTENSION_RAD 
k_r_i21e 
twomass_xsc 
2MASS 
K 21mag/sq." isophotal elliptical ap. semimajor axis. 
real 
4 
arcsec 

EXTENSION_RAD 
k_resid_ann 
twomass_xsc 
2MASS 
K residual annulus background median. 
real 
4 
DN 

CODE_MISC 
k_sc_1mm 
twomass_xsc 
2MASS 
K 1st moment (score) (LCSB: super blk 2,4,8 SNR). 
real 
4 


CODE_MISC 
k_sc_2mm 
twomass_xsc 
2MASS 
K 2nd moment (score) (LCSB: SNRMAX  super SNR max). 
real 
4 


CODE_MISC 
k_sc_msh 
twomass_xsc 
2MASS 
K median shape score. 
real 
4 


CODE_MISC 
k_sc_mxdn 
twomass_xsc 
2MASS 
K mxdn (score) (LCSB: BSNR  block/smoothed SNR). 
real 
4 


CODE_MISC 
k_sc_r1 
twomass_xsc 
2MASS 
K r1 (score). 
real 
4 


CODE_MISC 
k_sc_r23 
twomass_xsc 
2MASS 
K r23 (score) (LCSB: TSNR  integrated SNR for r=15). 
real 
4 


CODE_MISC 
k_sc_sh 
twomass_xsc 
2MASS 
K shape (score). 
real 
4 


CODE_MISC 
k_sc_vint 
twomass_xsc 
2MASS 
K vint (score). 
real 
4 


CODE_MISC 
k_sc_wsh 
twomass_xsc 
2MASS 
K wsh (score) (LCSB: PSNR  peak raw SNR). 
real 
4 


CODE_MISC 
k_seetrack 
twomass_xsc 
2MASS 
K band seetracking score. 
real 
4 


CODE_MISC 
k_sh0 
twomass_xsc 
2MASS 
K ridge shape (LCSB: BSNR limit). 
real 
4 


FIT_PARAM 
k_shape_avg 
twomass_scn 
2MASS 
Ksband average seeing shape for scan. 
real 
4 


INST_SEEING 
k_shape_avg 
twomass_sixx2_scn 
2MASS 
K band average seeing shape for scan 
real 
4 



k_shape_rms 
twomass_scn 
2MASS 
RMSerror of Ksband average seeing shape. 
real 
4 


INST_SEEING 
k_shape_rms 
twomass_sixx2_scn 
2MASS 
rms of K band avg seeing shape for scan 
real 
4 



k_sig_sh0 
twomass_xsc 
2MASS 
K ridge shape sigma (LCSB: B2SNR limit). 
real 
4 


FIT_PARAM 
k_snr 
twomass_psc 
2MASS 
Ksband "scan" signaltonoise ratio. 
real 
4 
mag 

INST_NOISE 
k_snr 
twomass_sixx2_psc 
2MASS 
K band "scan" signaltonoise ratio 
real 
4 



k_subst2 
twomass_xsc 
2MASS 
K residual background #2 (score). 
real 
4 


CODE_MISC 
k_zp_ap 
twomass_scn 
2MASS 
Photometric zeropoint for Ksband aperture photometry. 
real 
4 
mag 

PHOT_ZP 
k_zp_ap 
twomass_sixx2_scn 
2MASS 
K band ap. calibration photometric zeropoint for scan 
real 
4 
mag 


k_zperr_ap 
twomass_scn 
2MASS 
RMSerror of zeropoint for Ksband aperture photometry 
real 
4 
mag 

FIT_ERROR 
k_zperr_ap 
twomass_sixx2_scn 
2MASS 
K band ap. calibration rms error of zeropoint for scan 
real 
4 
mag 


kAperMag1 
calSynopticSource 
WSACalib 
Extended source K aperture corrected mag (0.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag1Err 
calSynopticSource 
WSACalib 
Error in extended source K mag (0.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag2 
calSynopticSource 
WSACalib 
Extended source K aperture corrected mag (1.4 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag2Err 
calSynopticSource 
WSACalib 
Error in extended source K mag (1.4 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag3 
calSource 
WSACalib 
Default point/extended source K aperture corrected mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag3 
calSynopticSource 
WSACalib 
Default point/extended source K aperture corrected mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag3 
dxsJKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Default point/extended source K aperture corrected mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag3 
dxsSource, lasSource 
WSA 
Default point/extended source K aperture corrected mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag3 
reliableUdsSource 
WSA 
Default point/extended source K mag, no aperture correction applied 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag3 
udsSource 
WSA 
Default point/extended source K mag, no aperture correction applied If in doubt use this flux estimator 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag3Err 
calSource, calSynopticSource 
WSACalib 
Error in default point/extended source K mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag3Err 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
Error in default point/extended source K mag (2.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag4 
calSource, calSynopticSource 
WSACalib 
Extended source K aperture corrected mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag4 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Extended source K aperture corrected mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag4 
reliableUdsSource, udsSource 
WSA 
Extended source K mag, no aperture correction applied 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag4Err 
calSource, calSynopticSource 
WSACalib 
Error in extended source K mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag4Err 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
Error in extended source K mag (2.8 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag5 
calSynopticSource 
WSACalib 
Extended source K aperture corrected mag (4.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag5Err 
calSynopticSource 
WSACalib 
Error in extended source K mag (4.0 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag6 
calSource 
WSACalib 
Extended source K aperture corrected mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag6 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Extended source K aperture corrected mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag6 
reliableUdsSource, udsSource 
WSA 
Extended source K mag, no aperture correction applied 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kAperMag6Err 
calSource 
WSACalib 
Error in extended source K mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kAperMag6Err 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
Error in extended source K mag (5.7 arcsec aperture diameter) 
real 
4 
mag 
0.9999995e9 
ERROR 
kaStratAst 
calVarFrameSetInfo 
WSACalib 
Strateva parameter, a, in fit to astrometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kaStratAst 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Strateva parameter, a, in fit to astrometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kaStratPht 
calVarFrameSetInfo 
WSACalib 
Strateva parameter, a, in fit to photometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kaStratPht 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Strateva parameter, a, in fit to photometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kbestAper 
calVariability 
WSACalib 
Best aperture (16) for photometric statistics in the K band 
int 
4 

9999 

Aperture magnitude (16) 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) 
kbestAper 
dxsVariability, udsVariability 
WSA 
Best aperture (16) for photometric statistics in the K band 
int 
4 

9999 

Aperture magnitude (16) 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) 
kbStratAst 
calVarFrameSetInfo 
WSACalib 
Strateva parameter, b, in fit to astrometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kbStratAst 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Strateva parameter, b, in fit to astrometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kbStratPht 
calVarFrameSetInfo 
WSACalib 
Strateva parameter, b, in fit to photometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kbStratPht 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Strateva parameter, b, in fit to photometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kchiSqAst 
calVarFrameSetInfo 
WSACalib 
Goodness of fit of Strateva function to astrometric data in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kchiSqAst 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Goodness of fit of Strateva function to astrometric data in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kchiSqpd 
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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kchiSqpd 
dxsVariability, udsVariability 
WSA 
Chi square (per degree of freedom) fit to data (mean and expected rms) 
real 
4 

0.9999995e9 

The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kchiSqPht 
calVarFrameSetInfo 
WSACalib 
Goodness of fit of Strateva function to photometric data in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kchiSqPht 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Goodness of fit of Strateva function to photometric data in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kClass 
calSource, calSynopticSource 
WSACalib 
discrete image classification flag in K 
smallint 
2 

9999 
CLASS_MISC 
kClass 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
discrete image classification flag in K 
smallint 
2 

9999 
CLASS_MISC 
kClassStat 
calSource, calSynopticSource 
WSACalib 
N(0,1) stellarnessofprofile statistic in K 
real 
4 

0.9999995e9 
STAT_PROP 
kClassStat 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
N(0,1) stellarnessofprofile statistic in K 
real 
4 

0.9999995e9 
STAT_PROP 
kClassStat 
reliableUdsSource, udsSource 
WSA 
SExtractor classification statistic in K 
real 
4 

0.9999995e9 
STAT_PROP 
kcStratAst 
calVarFrameSetInfo 
WSACalib 
Strateva parameter, c, in fit to astrometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kcStratAst 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Strateva parameter, c, in fit to astrometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
kcStratPht 
calVarFrameSetInfo 
WSACalib 
Strateva parameter, c, in fit to photometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kcStratPht 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Strateva parameter, c, in fit to photometric rms vs magnitude in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
kDeblend 
calSource 
WSACalib 
placeholder flag indicating parent/child relation in K 
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 postprocessing software based on testing the areal profiles aprof28 (these are set by CASU to 1 for deblended components, or positive values for nondeblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables. 
kDeblend 
calSynopticSource 
WSACalib 
placeholder flag indicating parent/child relation in K 
int 
4 

99999999 
CODE_MISC 
kDeblend 
dxsJKsource, lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
placeholder flag indicating parent/child relation in K 
int 
4 

99999999 
CODE_MISC 
kDeblend 
dxsSource, lasSource 
WSA 
placeholder flag indicating parent/child relation in K 
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 postprocessing software based on testing the areal profiles aprof28 (these are set by CASU to 1 for deblended components, or positive values for nondeblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables. 
kEll 
calSource, calSynopticSource 
WSACalib 
1b/a, where a/b=semimajor/minor axes in K 
real 
4 

0.9999995e9 
PHYS_ELLIPTICITY 
kEll 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
1b/a, where a/b=semimajor/minor axes in K 
real 
4 

0.9999995e9 
PHYS_ELLIPTICITY 
keNum 
calMergeLog, calSynopticMergeLog 
WSACalib 
the extension number of this K frame 
tinyint 
1 


NUMBER 
keNum 
dxsJKmergeLog, dxsMergeLog, lasMergeLog, lasYJHKmergeLog, udsMergeLog 
WSA 
the extension number of this K frame 
tinyint 
1 


NUMBER 
kErrBits 
calSource, calSynopticSource 
WSACalib 
processing warning/error bitwise flags in K 
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. 
kErrBits 
dxsJKsource, lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource 
WSA 
processing warning/error bitwise flags in K 
int 
4 

99999999 
CODE_MISC 
kErrBits 
dxsSource, lasSource 
WSA 
processing warning/error bitwise flags in K 
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. 
kErrBits 
udsSource 
WSA 
processing warning/error bitwise flags in K 
int 
4 

99999999 
CODE_MISC 
This uses the FLAGS attribute in SE. The individual bit flags that this can be decomposed into are as follows: Bit Flag  Meaning   1  The object has neighbours, bright enough and close enough to significantly bias the MAG_AUTO photometry or bad pixels (more than 10% of photometry affected).   2  The object was originally blended with another   4  At least one pixel is saturated (or very close to)   8  The object is truncated (too close to an image boundary)   16  Object's aperture data are incomplete or corrupted   32  Object's isophotal data are imcomplete or corrupted. This is an old flag inherited from SE v1.0, and is kept for compatability reasons. It doesn't have any consequence for the extracted parameters.   64  Memory overflow occurred during deblending   128  Memory overflow occurred during extraction  

kEta 
calSource, calSynopticSource 
WSACalib 
Offset of K 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 nonsurvey 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. 
kEta 
dxsJKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource 
WSA 
Offset of K detection from master position (+north/south) 
real 
4 
arcsec 
0.9999995e9 
POS_EQ_DEC_OFF 
kEta 
dxsSource, lasSource, udsSource 
WSA 
Offset of K 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 nonsurvey 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. 
kexpML 
calVarFrameSetInfo 
WSACalib 
Expected magnitude limit of frameSet in this in K 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. 
kexpML 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Expected magnitude limit of frameSet in this in K 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. 
kExpRms 
calVariability 
WSACalib 
Rms calculated from polynomial fit to modal RMS as a function of magnitude in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kExpRms 
dxsVariability, udsVariability 
WSA 
Rms calculated from polynomial fit to modal RMS as a function of magnitude in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kGausig 
calSource, calSynopticSource 
WSACalib 
RMS of axes of ellipse fit in K 
real 
4 
pixels 
0.9999995e9 
MORPH_PARAM 
kGausig 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
RMS of axes of ellipse fit in K 
real 
4 
pixels 
0.9999995e9 
MORPH_PARAM 
kHallMag 
calSource 
WSACalib 
Total point source K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kHallMag 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Total point source K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kHallMag 
reliableUdsSource, udsSource 
WSA 
Not available in SE output 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kHallMagErr 
calSource 
WSACalib 
Error in total point source K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
kHallMagErr 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Error in total point source K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
kHallMagErr 
reliableUdsSource, udsSource 
WSA 
Not available in SE output 
real 
4 
mag 
0.9999995e9 
ERROR 
kIntRms 
calVariability 
WSACalib 
Intrinsic rms in Kband 
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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kIntRms 
dxsVariability, udsVariability 
WSA 
Intrinsic rms in Kband 
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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kisDefAst 
calVarFrameSetInfo 
WSACalib 
Use a default model for the astrometric noise in K band. 
tinyint 
1 

0 

kisDefAst 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Use a default model for the astrometric noise in K band. 
tinyint 
1 

0 

kisDefPht 
calVarFrameSetInfo 
WSACalib 
Use a default model for the photometric noise in K band. 
tinyint 
1 

0 

kisDefPht 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Use a default model for the photometric noise in K band. 
tinyint 
1 

0 

kMag 
lasSourceRemeasurement 
WSA 
K mag (as appropriate for this merged source) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kMag 
ukirtFSstars 
WSA 
K band total magnitude on the MKO(UFTI) system 
real 
4 
mag 

PHOT_INTMAG 
kMag 
ukirtFSstars 
WSACalib 
K band total magnitude on the MKO(UFTI) system 
real 
4 
mag 

PHOT_INTMAG 
kMag 
ukirtFSstars 
WSAUHS 
K band total magnitude on the MKO(UFTI) system 
real 
4 
mag 

PHOT_INTMAG 
kMagErr 
lasSourceRemeasurement 
WSA 
Error in K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
kMagErr 
ukirtFSstars 
WSA 
K band magnitude error 
real 
4 
mag 

ERROR 
kMagErr 
ukirtFSstars 
WSACalib 
K band magnitude error 
real 
4 
mag 

ERROR 
kMagErr 
ukirtFSstars 
WSAUHS 
K band magnitude error 
real 
4 
mag 

ERROR 
kMagMAD 
calVariability 
WSACalib 
Median Absolute Deviation of K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kMagMAD 
dxsVariability, udsVariability 
WSA 
Median Absolute Deviation of K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kMagRms 
calVariability 
WSACalib 
rms of K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kMagRms 
dxsVariability, udsVariability 
WSA 
rms of K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kmaxCadence 
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. 
kmaxCadence 
dxsVariability, udsVariability 
WSA 
maximum gap between observations 
real 
4 
days 
0.9999995e9 

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable. 
kMaxMag 
calVariability 
WSACalib 
Maximum magnitude in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kMaxMag 
dxsVariability, udsVariability 
WSA 
Maximum magnitude in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kmeanMag 
calVariability 
WSACalib 
Mean K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kmeanMag 
dxsVariability, udsVariability 
WSA 
Mean K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kmedCadence 
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. 
kmedCadence 
dxsVariability, udsVariability 
WSA 
median gap between observations 
real 
4 
days 
0.9999995e9 

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable. 
kmedianMag 
calVariability 
WSACalib 
Median K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kmedianMag 
dxsVariability, udsVariability 
WSA 
Median K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kmfID 
calMergeLog, calSynopticMergeLog 
WSACalib 
the UID of the relevant K multiframe 
bigint 
8 


ID_FRAME 
kmfID 
dxsJKmergeLog, dxsMergeLog, lasMergeLog, lasYJHKmergeLog, udsMergeLog 
WSA 
the UID of the relevant K multiframe 
bigint 
8 


ID_FRAME 
kminCadence 
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. 
kminCadence 
dxsVariability, udsVariability 
WSA 
minimum gap between observations 
real 
4 
days 
0.9999995e9 

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable. 
kMinMag 
calVariability 
WSACalib 
Minimum magnitude in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kMinMag 
dxsVariability, udsVariability 
WSA 
Minimum magnitude in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kndof 
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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kndof 
dxsVariability, udsVariability 
WSA 
Number of degrees of freedom for chisquare 
smallint 
2 

9999 

The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
knDofAst 
calVarFrameSetInfo 
WSACalib 
Number of degrees of freedom of astrometric fit in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
knDofAst 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Number of degrees of freedom of astrometric fit in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. 
knDofPht 
calVarFrameSetInfo 
WSACalib 
Number of degrees of freedom of photometric fit in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
knDofPht 
dxsVarFrameSetInfo, udsVarFrameSetInfo 
WSA 
Number of degrees of freedom of photometric fit in K 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 medianabsolute 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 chisquared and number of degrees of freedom are also calculated. This technique was used in Sesar et al. 2007, AJ, 134, 2236. 
knFlaggedObs 
calVariability 
WSACalib 
Number of detections in K 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. 
knFlaggedObs 
dxsVariability 
WSA 
Number of detections in K band flagged as potentially spurious by dxsDetection.ppErrBits 
int 
4 

0 

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable. 
knFlaggedObs 
udsVariability 
WSA 
Number of detections in K band flagged as potentially spurious by udsDetection.ppErrBits 
int 
4 

0 

The observations are classified as good, flagged or missing. Flagged observations are ones where the object has a ppErrBit flag. Missing observations are observations of the part of the sky that include the position of the object, but had no detection. All the statistics are calculated from good observations. The cadence parameters give the minimum, median and maximum time between observations, which is useful to know if the data could be used to find a particular type of variable. 
knGoodObs 
calVariability 
WSACalib 
Number of good detections in K 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. 
knGoodObs 
dxsVariability, udsVariability 
WSA 
Number of good detections in K 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. 
kNgt3sig 
calVariability 
WSACalib 
Number of good detections in Kband 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kNgt3sig 
dxsVariability, udsVariability 
WSA 
Number of good detections in Kband 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
knMissingObs 
calVariability 
WSACalib 
Number of K 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. 
knMissingObs 
dxsVariability, udsVariability 
WSA 
Number of K 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. 
kObjID 
lasExtendedSource, lasPointSource, lasYJHKsource, reliableLasPointSource 
WSA 
DEPRECATED (do not use) 
bigint 
8 

99999999 
ID_NUMBER 
kObjID 
lasSource, lasSourceRemeasurement 
WSA 
DEPRECATED (do not use) 
bigint 
8 

99999999 
ID_NUMBER 
This attribute is included in source tables for historical reasons, but it's use is not recommended unless you really know what you are doing. In general, if you need to look up detection table attributes for a source in a given passband that are not in the source table, you should make an SQL join between source, mergelog and detection using the primary key attribute frameSetID and combination multiframeID, extNum, seqNum to associate related rows between the three tables. See the Q&A example SQL for more information. 
kPA 
calSource, calSynopticSource 
WSACalib 
ellipse fit celestial orientation in K 
real 
4 
Degrees 
0.9999995e9 
POS_POSANG 
kPA 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
ellipse fit celestial orientation in K 
real 
4 
Degrees 
0.9999995e9 
POS_POSANG 
kPetroMag 
calSource 
WSACalib 
Extended source K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kPetroMag 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
Extended source K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kPetroMagErr 
calSource 
WSACalib 
Error in extended source K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
ERROR 
kPetroMagErr 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
Error in extended source K mag (Petrosian) 
real 
4 
mag 
0.9999995e9 
ERROR 
kppErrBits 
calSource, calSynopticSource 
WSACalib 
additional WFAU postprocessing error bits in K 
int 
4 

0 
CODE_MISC 
Postprocessing 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 4byte 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. 
kppErrBits 
dxsJKsource, lasExtendedSource, lasPointSource, lasSourceRemeasurement, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
additional WFAU postprocessing error bits in K 
int 
4 

0 
CODE_MISC 
kppErrBits 
dxsSource, lasSource 
WSA 
additional WFAU postprocessing error bits in K 
int 
4 

0 
CODE_MISC 
Postprocessing 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 4byte 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. 
kprobVar 
calVariability 
WSACalib 
Probability of variable from chisquare (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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kprobVar 
dxsVariability, udsVariability 
WSA 
Probability of variable from chisquare (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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kPsfMag 
calSource 
WSACalib 
Point source profilefitted K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kPsfMag 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Point source profilefitted K mag 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kPsfMag 
reliableUdsSource, udsSource 
WSA 
Not available in SE output 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kPsfMagErr 
calSource 
WSACalib 
Error in point source profilefitted K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
kPsfMagErr 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Error in point source profilefitted K mag 
real 
4 
mag 
0.9999995e9 
ERROR 
kPsfMagErr 
reliableUdsSource, udsSource 
WSA 
Not available in SE output 
real 
4 
mag 
0.9999995e9 
ERROR 
kronFlux 
UKIDSSDetection 
WSA 
flux within circular aperture to k × r_k ; k = 2 
real 
4 
ADU 

PHOT_INTENSITY_ADU 
kronFlux 
calDetection 
WSACalib 
flux within circular aperture to k × r_k ; k = 2 {catalogue TType keyword: Kron_flux} 
real 
4 
ADU 

PHOT_INTENSITY_ADU 
kronFlux 
dxsDetection, gcsDetection, gcsListRemeasurement, gpsDetection, gpsListRemeasurement, lasDetection, lasListRemeasurement 
WSA 
flux within circular aperture to k × r_k ; k = 2 {catalogue TType keyword: Kron_flux} 
real 
4 
ADU 

PHOT_INTENSITY_ADU 
kronFlux 
ptsDetection 
WSATransit 
flux within circular aperture to k × r_k ; k = 2 {catalogue TType keyword: Kron_flux} 
real 
4 
ADU 

PHOT_INTENSITY_ADU 
kronFlux 
udsDetection 
WSA 
flux within Kron radius circular aperture (SE: FLUX_AUTO) {catalogue TType keyword: Kron_flux} 
real 
4 
ADU 

PHOT_INTENSITY_ADU 
kronFlux 
uhsDetection, uhsDetectionAll 
WSAUHS 
flux within circular aperture to k × r_k ; k = 2 {catalogue TType keyword: Kron_flux} 
real 
4 
ADU 

PHOT_INTENSITY_ADU 
kronFluxErr 
UKIDSSDetection 
WSA 
error on Kron flux 
real 
4 
ADU 

ERROR 
kronFluxErr 
calDetection 
WSACalib 
error on Kron flux {catalogue TType keyword: Kron_flux_err} 
real 
4 
ADU 

ERROR 
kronFluxErr 
dxsDetection, gcsDetection, gcsListRemeasurement, gpsDetection, gpsListRemeasurement, lasDetection, lasListRemeasurement 
WSA 
error on Kron flux {catalogue TType keyword: Kron_flux_err} 
real 
4 
ADU 

ERROR 
kronFluxErr 
ptsDetection 
WSATransit 
error on Kron flux {catalogue TType keyword: Kron_flux_err} 
real 
4 
ADU 

ERROR 
kronFluxErr 
udsDetection 
WSA 
error on Kron flux (SE: FLUXERR_AUTO) {catalogue TType keyword: Kron_flux_err} 
real 
4 
ADU 

ERROR 
kronFluxErr 
uhsDetection, uhsDetectionAll 
WSAUHS 
error on Kron flux {catalogue TType keyword: Kron_flux_err} 
real 
4 
ADU 

ERROR 
kronMag 
dxsDetection, gcsDetection, gcsListRemeasurement, gpsDetection, gpsListRemeasurement, lasDetection, lasListRemeasurement, UKIDSSDetection, udsDetection 
WSA 
Calibrated Kron magnitude within circular aperture r_k 
real 
4 
mag 

PHOT_INTMAG 
kronMag 
calDetection 
WSACalib 
Calibrated Kron magnitude within circular aperture r_k 
real 
4 
mag 

PHOT_INTMAG 
kronMag 
ptsDetection 
WSATransit 
Calibrated Kron magnitude within circular aperture r_k 
real 
4 
mag 

PHOT_INTMAG 
kronMag 
uhsDetection, uhsDetectionAll 
WSAUHS 
Calibrated Kron magnitude within circular aperture r_k 
real 
4 
mag 

PHOT_INTMAG 
kronMagErr 
dxsDetection, gcsDetection, gcsListRemeasurement, gpsDetection, gpsListRemeasurement, lasDetection, lasListRemeasurement, UKIDSSDetection, udsDetection 
WSA 
error on calibrated Kron magnitude 
real 
4 
mag 

ERROR 
kronMagErr 
calDetection 
WSACalib 
error on calibrated Kron magnitude 
real 
4 
mag 

ERROR 
kronMagErr 
ptsDetection 
WSATransit 
error on calibrated Kron magnitude 
real 
4 
mag 

ERROR 
kronMagErr 
uhsDetection, uhsDetectionAll 
WSAUHS 
error on calibrated Kron magnitude 
real 
4 
mag 

ERROR 
kronRad 
UKIDSSDetection 
WSA 
r_k as defined in Bertin and Arnouts 1996 A&A Supp 117 393 
real 
4 
pixels 

EXTENSION_RAD 
kronRad 
calDetection 
WSACalib 
r_k as defined in Bertin and Arnouts 1996 A&A Supp 117 393 {catalogue TType keyword: Kron_radius} 
real 
4 
pixels 

EXTENSION_RAD 
kronRad 
dxsDetection, gcsDetection, gcsListRemeasurement, gpsDetection, gpsListRemeasurement, lasDetection, lasListRemeasurement 
WSA 
r_k as defined in Bertin and Arnouts 1996 A&A Supp 117 393 {catalogue TType keyword: Kron_radius} 
real 
4 
pixels 

EXTENSION_RAD 
kronRad 
ptsDetection 
WSATransit 
r_k as defined in Bertin and Arnouts 1996 A&A Supp 117 393 {catalogue TType keyword: Kron_radius} 
real 
4 
pixels 

EXTENSION_RAD 
kronRad 
udsDetection 
WSA 
Kron radius as defined in SE by Graham and Driver (2005) (SE: KRON_RADIUS*A_IMAGE) {catalogue TType keyword: Kron_radius} r_k = ∑R² I(R) / ∑R I(R) 
real 
4 
pixels 

EXTENSION_RAD 
Since <FLUX>_RADIUS is expressed in multiples of the major axis, <FLUX>_RADIUS is multiplied by A_IMAGE to convert to pixels. 
kronRad 
uhsDetection, uhsDetectionAll 
WSAUHS 
r_k as defined in Bertin and Arnouts 1996 A&A Supp 117 393 {catalogue TType keyword: Kron_radius} 
real 
4 
pixels 

EXTENSION_RAD 
kSeqNum 
calSource, calSynopticSource 
WSACalib 
the running number of the K detection 
int 
4 

99999999 
ID_NUMBER 
kSeqNum 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource, udsSource 
WSA 
the running number of the K detection 
int 
4 

99999999 
ID_NUMBER 
kSeqNum 
lasSourceRemeasurement 
WSA 
the running number of the K remeasurement 
int 
4 

99999999 
ID_NUMBER 
kSerMag2D 
calSource 
WSACalib 
Extended source K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kSerMag2D 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Extended source K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kSerMag2D 
reliableUdsSource, udsSource 
WSA 
Not available in SE output 
real 
4 
mag 
0.9999995e9 
PHOT_MAG 
kSerMag2DErr 
calSource 
WSACalib 
Error in extended source K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
ERROR 
kSerMag2DErr 
dxsJKsource, dxsSource, lasExtendedSource, lasPointSource, lasSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource 
WSA 
Error in extended source K mag (profilefitted) 
real 
4 
mag 
0.9999995e9 
ERROR 
kSerMag2DErr 
reliableUdsSource, udsSource 
WSA 
Not available in SE output 
real 
4 
mag 
0.9999995e9 
ERROR 
kskewness 
calVariability 
WSACalib 
Skewness in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kskewness 
dxsVariability, udsVariability 
WSA 
Skewness in K 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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
ktotalPeriod 
calVariability 
WSACalib 
total period of observations (last obsfirst 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. 
ktotalPeriod 
dxsVariability, udsVariability 
WSA 
total period of observations (last obsfirst 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. 
kurtosis 
phot_variable_time_series_g_fov_statistical_parameters 
GAIADR1 
Standardized unweighted kurtosis of the Gband time series values 
float 
8 


stat.value 
kVarClass 
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 chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kVarClass 
dxsVariability, udsVariability 
WSA 
Classification of variability in this band 
smallint 
2 

9999 

The photometry is calculated for good observations in the best aperture. The mean, rms, median, median absolute deviation, minMag and maxMag are quite standard. The skewness is calculated as in Sesar et al. 2007, AJ, 134, 2236. The number of good detections that are more than 3 standard deviations can indicate a distribution with many outliers. In each frameset, the mean and rms are used to derive a fit to the expected rms as a function of magnitude. The parameters for the fit are stored in VarFrameSetInfo and the value for the source is in expRms. This is subtracted from the rms in quadrature to get the intrinsic rms: the variability of the object beyond the noise in the system. The chisquared is calculated, assuming a nonvariable object which has the noise from the expectedrms and mean calculated as above. The probVar statistic assumes a chisquared distribution with the correct number of degrees of freedom. The varClass statistic is 1, if the probVar>0.9 and intrinsicRMS/expectedRMS>3. 
kXi 
calSource, calSynopticSource 
WSACalib 
Offset of K 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 nonsurvey 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. 
kXi 
dxsJKsource, lasExtendedSource, lasPointSource, lasYJHKsource, reliableDxsSource, reliableLasPointSource, reliableUdsSource 
WSA 
Offset of K detection from master position (+east/west) 
real 
4 
arcsec 
0.9999995e9 
POS_EQ_RA_OFF 
kXi 
dxsSource, lasSource, udsSource 
WSA 
Offset of K 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 nonsurvey 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. 