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Glossary of WSA NonSurvey attributes (UKIDSSDR2)
This Glossary alphabetically lists all attributes used in the WSA NonSurvey database(s) held in the WSA. If you would like to have more information about the schema tables please use the Schema Browser (other Browser versions).

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Y
Name	Schema Table	Database	Description	Type	Length	Unit	Default Value	Unified Content Descriptor
y	[nspid]Detection	WSA NonSurvey	Y coordinate of detection {catalogue TType keyword: Y_coordinate} Intensity-weighted isophotal centre-of-gravity in Y.	real	4	pixels		POS_PLATE_Y
yAperMag3	[nspid]Source	WSA NonSurvey	Default point/extended source Y aperture corrected mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator	real	4	mag	-0.9999995e9	PHOT_MAG
yAperMag3	[nspid]Source	WSA NonSurvey	Default point/extended source Y mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator	real	4	mag	-0.9999995e9	PHOT_MAG
yAperMag3Err	[nspid]Source	WSA NonSurvey	Error in default point/extended source Y mag (2.0 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
yAperMag4	[nspid]Source	WSA NonSurvey	Extended source Y aperture corrected mag (2.8 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
yAperMag4	[nspid]Source	WSA NonSurvey	Extended source Y mag (2.8 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
yAperMag4Err	[nspid]Source	WSA NonSurvey	Error in extended source Y mag (2.8 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
yAperMag6	[nspid]Source	WSA NonSurvey	Extended source Y aperture corrected mag (5.7 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
yAperMag6	[nspid]Source	WSA NonSurvey	Extended source Y mag (5.7 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
yAperMag6Err	[nspid]Source	WSA NonSurvey	Error in extended source Y mag (5.7 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
yClass	[nspid]Source	WSA NonSurvey	discrete image classification flag in Y	smallint	2		-9999	CLASS_MISC
yClassStat	[nspid]Source	WSA NonSurvey	N(0,1) stellarness-of-profile statistic in Y	real	4		-0.9999995e9	STAT_PROP
yDeblend	[nspid]Source	WSA NonSurvey	flag indicating parent/child relation in Y	int	4		-99999999	CODE_MISC
yEll	[nspid]Source	WSA NonSurvey	1-b/a, where a/b=semi-major/minor axes in Y	real	4		-0.9999995e9	PHYS_ELLIPTICITY
yeNum	[nspid]MergeLog	WSA NonSurvey	the extension number of this Y detector	tinyint	1			NUMBER
yErr	[nspid]Detection	WSA NonSurvey	Error in Y coordinate {catalogue TType keyword: Y_coordinate_err} Estimate of centroid error.	real	4	pixels		ERROR
yErrBits	[nspid]Source	WSA NonSurvey	processing warning/error bitwise flags in Y	int	4		-99999999	CODE_MISC
yEta	[nspid]Source	WSA NonSurvey	Offset of Y detection from master position (+north/-south)	real	4	arcsec	-0.9999995e9	POS_EQ_DEC_OFF
			When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want.
yGausig	[nspid]Source	WSA NonSurvey	RMS of axes of ellipse fit in Y	real	4	pixels	-0.9999995e9	MORPH_PARAM
yHallMag	[nspid]Source	WSA NonSurvey	Total point source Y mag	real	4	mag	-0.9999995e9	PHOT_MAG
yHallMagErr	[nspid]Source	WSA NonSurvey	Error in total point source Y mag	real	4	mag	-0.9999995e9	ERROR
yMag	[nspid]CurrentStdStarInfo, [nspid]PreviousStdStarInfo	WSA NonSurvey	Y band total magnitude of star (from external sources if primary)	real	4	mag		PHOT_INT-MAG
yMagErr	[nspid]CurrentStdStarInfo, [nspid]PreviousStdStarInfo	WSA NonSurvey	Y band magnitude error of star	real	4	mag		ERROR
ymfID	[nspid]MergeLog	WSA NonSurvey	the UID of the relevant Y multiframe	bigint	8			ID_FRAME
ymjExt	[nspid]Source	WSA NonSurvey	Extended source colour Y-J (using aperMag3)	real	4	mag	-0.9999995e9	PHOT_COLOR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
ymjExt	[nspid]Source	WSA NonSurvey	Extended source colour Y-J	real	4	mag	-0.9999995e9	PHOT_COLOR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
ymjExtErr	[nspid]Source	WSA NonSurvey	Error on extended source colour Y-J	real	4	mag	-0.9999995e9	ERROR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
ymjPnt	[nspid]Source	WSA NonSurvey	Point source colour Y-J (using AperMag3)	real	4	mag	-0.9999995e9	PHOT_COLOR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
ymjPnt	[nspid]Source	WSA NonSurvey	Point source colour Y-J (using aperMag3)	real	4	mag	-0.9999995e9	PHOT_COLOR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
ymjPntErr	[nspid]Source	WSA NonSurvey	Error on point source colour Y-J	real	4	mag	-0.9999995e9	ERROR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
yObjID	[nspid]Source	WSA NonSurvey	the UID of the Y detection	bigint	8		-99999999	ID_NUMBER
yPA	[nspid]Source	WSA NonSurvey	ellipse fit celestial orientation in Y	real	4	Degrees	-0.9999995e9	POS_POS-ANG
yPetroMag	[nspid]Source	WSA NonSurvey	Extended source Y mag (Petrosian)	real	4	mag	-0.9999995e9	PHOT_MAG
yPetroMagErr	[nspid]Source	WSA NonSurvey	Error in extended source Y mag (Petrosian)	real	4	mag	-0.9999995e9	ERROR
yPixSize	[nspid]CurrentAstrometry, [nspid]PreviousAstrometry	WSA NonSurvey	Angular size of pixels in Y	real	4	Arcseconds	-0.9999995e9	POS_ANG_DIST_GENERAL
yppErrBits	[nspid]Source	WSA NonSurvey	additional WFAU post-processing error bits in Y	int	4		-99999999	CODE_MISC
yppErrBits	[nspid]Source	WSA NonSurvey	additional WFAU post-processing error bits in Y	int	4		0	CODE_MISC
yPsfMag	[nspid]Source	WSA NonSurvey	Point source profile-fitted Y mag	real	4	mag	-0.9999995e9	PHOT_MAG
yPsfMagErr	[nspid]Source	WSA NonSurvey	Error in point source profile-fitted Y mag	real	4	mag	-0.9999995e9	ERROR
ySeqNum	[nspid]Source	WSA NonSurvey	the running number of the Y detection	int	4		-99999999	ID_NUMBER
ySerMag2D	[nspid]Source	WSA NonSurvey	Extended source Y mag (profile-fitted)	real	4	mag	-0.9999995e9	PHOT_MAG
ySerMag2DErr	[nspid]Source	WSA NonSurvey	Error in extended source Y mag (profile-fitted)	real	4	mag	-0.9999995e9	ERROR
ySize	[nspid]MultiframeDetector	WSA NonSurvey	Corresponding image size (Y); value only available if catalogue file exists {catalogue extension keyword:  NYOUT}	int	4		-99999999	NUMBER
yXi	[nspid]Source	WSA NonSurvey	Offset of Y detection from master position (+east/-west)	real	4	arcsec	-0.9999995e9	POS_EQ_RA_OFF
			When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 2.0 (UKIDSS LAS and GPS; also non-survey programmes) or 1.0 (UKIDSS GPS, DXS and UDS) arcseconds is used, the higher value enabling pairing of moving sources when epoch separations may be several years. Such a large association criterion can of course lead to spurious pairings in the merged sources lists (although note that between passband pairs, handshake pairing is done: both passbands must agree that the candidate pair is their nearest neighbour for the pair to propagate through into the merged source table). In order to help filter spurious pairings out, and assuming that large positional offsets between the different passband detections are not expected (e.g. because of source motion, or larger than usual positional uncertainties) then the attributes Xi and Eta can be used to filter any pairings with suspiciously large offsets in one or more bands. For example, for a clean sample of QSOs from the LAS, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want.