Home | Overview | Browser | Access | Login | Cookbook | nonSurvey  ** Announcement - Workshop: Science from UKIDSS II, 15-17 Dec 2008, London UK **

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

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Z
Name	Schema Table	Database	Description	Type	Length	Unit	Default Value	Unified Content Descriptor
z11	Multiframe	WSA	Spherical: Z11 {image primary HDU keyword: Z11}	real	4		-0.9999995e9
z7	Multiframe	WSA	Coma: Z7 {image primary HDU keyword: Z7}	real	4		-0.9999995e9
z8	Multiframe	WSA	Coma: Z8 {image primary HDU keyword: Z8}	real	4		-0.9999995e9
zAperMag3	gcsSource	WSA	Default point/extended source Z aperture corrected mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator	real	4	mag	-0.9999995e9	PHOT_MAG
zAperMag3Err	gcsSource	WSA	Error in default point/extended source Z mag (2.0 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
zAperMag4	gcsSource	WSA	Extended source Z aperture corrected mag (2.8 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
zAperMag4Err	gcsSource	WSA	Error in extended source Z mag (2.8 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
zAperMag6	gcsSource	WSA	Extended source Z aperture corrected mag (5.7 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
zAperMag6Err	gcsSource	WSA	Error in extended source Z mag (5.7 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
zClass	gcsSource, gcsSourceRemeasurement	WSA	discrete image classification flag in Z	smallint	2		-9999	CLASS_MISC
zClassStat	gcsSource, gcsSourceRemeasurement	WSA	N(0,1) stellarness-of-profile statistic in Z	real	4		-0.9999995e9	STAT_PROP
zd	twomass_scn	2MASS	Scan's distance from the zenith at beginning of scan.	real	4	degrees		POS_ZD_RES
zDeblend	gcsSource, gcsSourceRemeasurement	WSA	flag indicating parent/child relation in Z	int	4		-99999999	CODE_MISC
zEll	gcsSource, gcsSourceRemeasurement	WSA	1-b/a, where a/b=semi-major/minor axes in Z	real	4		-0.9999995e9	PHYS_ELLIPTICITY
zeNum	gcsMergeLog	WSA	the extension number of this Z frame	tinyint	1			NUMBER
zErrBits	gcsSource, gcsSourceRemeasurement	WSA	processing warning/error bitwise flags in Z	int	4		-99999999	CODE_MISC
zEta	gcsSource	WSA	Offset of Z detection from master position (+north/-south)	real	4	arcsec	-0.9999995e9	POS_EQ_DEC_OFF
			When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of typically 5 arcseconds is used, 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, you might wish to insist that the offsets in the selected sample are all below 1 arcsecond: simply add WHERE clauses into the SQL sample selection script to exclude all Xi and Eta values larger than the threshold you want.
zGausig	gcsSource, gcsSourceRemeasurement	WSA	RMS of axes of ellipse fit in Z	real	4	pixels	-0.9999995e9	MORPH_PARAM
zHallMag	gcsSource	WSA	Total point source Z mag	real	4	mag	-0.9999995e9	PHOT_MAG
zHallMagErr	gcsSource	WSA	Error in total point source Z mag	real	4	mag	-0.9999995e9	ERROR
zMag	CurrentStdStarInfo, PreviousStdStarInfo	WSA	Z band total magnitude of star (from external sources if primary)	real	4	mag		PHOT_INT-MAG
zMag	gcsSourceRemeasurement	WSA	Z mag (as appropriate for this merged source)	real	4	mag	-0.9999995e9	PHOT_MAG
zMagErr	CurrentStdStarInfo, PreviousStdStarInfo	WSA	Z band magnitude error of star	real	4	mag		ERROR
zMagErr	gcsSourceRemeasurement	WSA	Error in Z mag	real	4	mag	-0.9999995e9	ERROR
zmfID	gcsMergeLog	WSA	the UID of the relevant Z multiframe	bigint	8			ID_FRAME
zmy	gcsSourceRemeasurement	WSA	Default colour Z-Y (using appropriate mags)	real	4	mag		PHOT_COLOR
zmyErr	gcsSourceRemeasurement	WSA	Error on colour Z-Y	real	4	mag		ERROR
zmyExt	gcsSource	WSA	Extended source colour Z-Y (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.
zmyExtErr	gcsSource	WSA	Error on extended source colour Z-Y	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.
zmyPnt	gcsSource	WSA	Point source colour Z-Y (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.
zmyPntErr	gcsSource	WSA	Error on point source colour Z-Y	real	4	mag	-0.9999995e9	ERROR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
zObjID	gcsSource	WSA	the UID of the Z detection	bigint	8		-99999999	ID_NUMBER
zObjID	gcsSourceRemeasurement	WSA	the UID of the Z remeasurement	bigint	8		-99999999	ID_NUMBER
zone	ExternalSurveyTable, ProgrammeTable	WSA	default (0) or special (n) zone	smallint	2			ID_REGION
zp0	CurrentZP	WSA	the zeroth-order zeropoint coefficient	float	8		0.0	PHOT_ZP
zp0	PreviousZP	WSA	the zeroth-order zeropoint coefficient	float	8			PHOT_ZP
zp1	CurrentZP	WSA	the first-order zeropoint coefficient wrt time during night	float	8		0.0	PHOT_ZP
zp1	PreviousZP	WSA	the first-order zeropoint coefficient wrt time during night	float	8			PHOT_ZP
zp2	CurrentZP	WSA	the second-order zeropoint coefficient wrt time during night	float	8		0.0	PHOT_ZP
zp2	PreviousZP	WSA	the second-order zeropoint coefficient wrt time during night	float	8			PHOT_ZP
zp3	CurrentZP	WSA	the first-order zeropoint coefficient wrt time across nights (long-term decay of detector)	float	8		0.0	PHOT_ZP
zp3	PreviousZP	WSA	the first-order zeropoint coefficient wrt time across nights (long-term decay of detector)	float	8			PHOT_ZP
zp4	CurrentZP	WSA	the second-order zeropoint coefficient wrt time across nights (long-term decay of detector)	float	8		0.0	PHOT_ZP
zp4	PreviousZP	WSA	the second-order zeropoint coefficient wrt time across nights (long-term decay of detector)	float	8			PHOT_ZP
zPA	gcsSource, gcsSourceRemeasurement	WSA	ellipse fit celestial orientation in Z	real	4	Degrees	-0.9999995e9	POS_POS-ANG
zPetroMag	gcsSource	WSA	Extended source Z mag (Petrosian)	real	4	mag	-0.9999995e9	PHOT_MAG
zPetroMagErr	gcsSource	WSA	Error in extended source Z mag (Petrosian)	real	4	mag	-0.9999995e9	ERROR
zppErrBits	gcsSource, gcsSourceRemeasurement	WSA	additional WFAU post-processing error bits in Z	int	4		0	CODE_MISC
zPsfMag	gcsSource	WSA	Point source profile-fitted Z mag	real	4	mag	-0.9999995e9	PHOT_MAG
zPsfMagErr	gcsSource	WSA	Error in point source profile-fitted Z mag	real	4	mag	-0.9999995e9	ERROR
zSeqNum	gcsSource	WSA	the running number of the Z detection	int	4		-99999999	ID_NUMBER
zSeqNum	gcsSourceRemeasurement	WSA	the running number of the Z remeasurement	int	4		-99999999	ID_NUMBER
zSerMag2D	gcsSource	WSA	Extended source Z mag (profile-fitted)	real	4	mag	-0.9999995e9	PHOT_MAG
zSerMag2DErr	gcsSource	WSA	Error in extended source Z mag (profile-fitted)	real	4	mag	-0.9999995e9	ERROR
zXi	gcsSource	WSA	Offset of Z detection from master position (+east/-west)	real	4	arcsec	-0.9999995e9	POS_EQ_RA_OFF
			When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of typically 5 arcseconds is used, 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, 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.