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Glossary of WSA NonSurvey attributes (UKIDSSDR8)
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

B
Name	Schema Table	Database	Description	Type	Length	Unit	Default Value	Unified Content Descriptor
b	[nspid]CurrentAstrometry, [nspid]PreviousAstrometry	WSA NonSurvey	Galactic latitude of device centre	float	8	Degrees		POS_GAL_LAT
b	[nspid]Detection, [nspid]Source, [nspid]SynopticSource	WSA NonSurvey	Galactic latitude	float	8	Degrees		POS_GAL_LAT
bandMergingCriterion	[nspid]Programme	WSA NonSurvey	maximum timespan over which different filters are merged into sources in the synoptic source table.	real	4	minutes	-0.9999995e9
beamNS	[nspid]Multiframe	WSA NonSurvey	Topend: N-S beam {image primary HDU keyword: NSBEAM}	real	4		-0.9999995e9
beamWE	[nspid]Multiframe	WSA NonSurvey	Topend: W-E beam {image primary HDU keyword: WEBEAM}	real	4		-0.9999995e9
bitsPerPix	[nspid]MultiframeDetector	WSA NonSurvey	Number of bits per data pixel, eg. +32 = 4 byte integers {image extension keyword: BITPIX}	smallint	2	FITS bitpix		NUMBER
bMag	[nspid]FSstars	WSA NonSurvey	B band total magnitude	real	4	mag	-0.9999995e9	PHOT_INT-MAG
brAperMag3	[nspid]Source	WSA NonSurvey	Default point/extended source Br aperture corrected mag (2.0 arcsec aperture diameter) If in doubt use this flux estimator	real	4	mag	-0.9999995e9	PHOT_MAG
brAperMag3Err	[nspid]Source	WSA NonSurvey	Error in default point/extended source Br mag (2.0 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
brAperMag4	[nspid]Source	WSA NonSurvey	Extended source Br aperture corrected mag (2.8 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
brAperMag4Err	[nspid]Source	WSA NonSurvey	Error in extended source Br mag (2.8 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
brAperMag6	[nspid]Source	WSA NonSurvey	Extended source Br aperture corrected mag (5.7 arcsec aperture diameter)	real	4	mag	-0.9999995e9	PHOT_MAG
brAperMag6Err	[nspid]Source	WSA NonSurvey	Error in extended source Br mag (5.7 arcsec aperture diameter)	real	4	mag	-0.9999995e9	ERROR
brClass	[nspid]Source	WSA NonSurvey	discrete image classification flag in Br	smallint	2		-9999	CLASS_MISC
brClassStat	[nspid]Source	WSA NonSurvey	N(0,1) stellarness-of-profile statistic in Br	real	4		-0.9999995e9	STAT_PROP
brDeblend	[nspid]Source	WSA NonSurvey	placeholder flag indicating parent/child relation in Br	int	4		-99999999	CODE_MISC
			This CASU pipeline processing source extraction flag is a placeholder only, and is always set to zero in all passbands in the merged source lists. If you need to know when a particular image detection is a component of a deblend or not, test bit 4 of attribute ppErrBits (see corresponding glossary entry) which is set by WFAU's post-processing software based on testing the areal profiles aprof2-8 (these are set by CASU to -1 for deblended components, or positive values for non-deblended detections). We encode this in an information bit of ppErrBits for convenience when querying the merged source tables.
brEll	[nspid]Source	WSA NonSurvey	1-b/a, where a/b=semi-major/minor axes in Br	real	4		-0.9999995e9	PHYS_ELLIPTICITY
breNum	[nspid]MergeLog	WSA NonSurvey	the extension number of this Br frame	tinyint	1			NUMBER
brErrBits	[nspid]Source	WSA NonSurvey	processing warning/error bitwise flags in Br	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.
brEta	[nspid]Source	WSA NonSurvey	Offset of Br 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.
brGausig	[nspid]Source	WSA NonSurvey	RMS of axes of ellipse fit in Br	real	4	pixels	-0.9999995e9	MORPH_PARAM
brHallMag	[nspid]Source	WSA NonSurvey	Total point source Br mag	real	4	mag	-0.9999995e9	PHOT_MAG
brHallMagErr	[nspid]Source	WSA NonSurvey	Error in total point source Br mag	real	4	mag	-0.9999995e9	ERROR
brmfID	[nspid]MergeLog	WSA NonSurvey	the UID of the relevant Br multiframe	bigint	8			ID_FRAME
brmkExt	[nspid]Source	WSA NonSurvey	Extended source colour Br-K (using aperMag3)	real	4	mag	-0.9999995e9	PHOT_COLOR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
brmkExtErr	[nspid]Source	WSA NonSurvey	Error on extended source colour Br-K	real	4	mag	-0.9999995e9	ERROR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
brmkPnt	[nspid]Source	WSA NonSurvey	Point source colour Br-K (using aperMag3)	real	4	mag	-0.9999995e9	PHOT_COLOR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
brmkPntErr	[nspid]Source	WSA NonSurvey	Error on point source colour Br-K	real	4	mag	-0.9999995e9	ERROR
			Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits.
brPA	[nspid]Source	WSA NonSurvey	ellipse fit celestial orientation in Br	real	4	Degrees	-0.9999995e9	POS_POS-ANG
brPetroMag	[nspid]Source	WSA NonSurvey	Extended source Br mag (Petrosian)	real	4	mag	-0.9999995e9	PHOT_MAG
brPetroMagErr	[nspid]Source	WSA NonSurvey	Error in extended source Br mag (Petrosian)	real	4	mag	-0.9999995e9	ERROR
brppErrBits	[nspid]Source	WSA NonSurvey	additional WFAU post-processing error bits in Br	int	4		0	CODE_MISC
			Post-processing error quality bit flags assigned (NB: from UKIDSS DR2 release onwards) in the WSA curation procedure for survey data. From least to most significant byte in the 4-byte integer attribute byte 0 (bits 0 to 7) corresponds to information on generally innocuous conditions that are nonetheless potentially significant as regards the integrity of that detection; byte 1 (bits 8 to 15) corresponds to warnings; byte 2 (bits 16 to 23) corresponds to important warnings; and finally byte 3 (bits 24 to 31) corresponds to severe warnings: Byte Bit Detection quality issue Threshold or bit mask Applies to Decimal Hexadecimal 0 4 Deblended 16 0x00000010 All VDFS catalogues 0 6 Bad pixel(s) in default aperture 64 0x00000040 All VDFS catalogues 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.
brPsfMag	[nspid]Source	WSA NonSurvey	Point source profile-fitted Br mag	real	4	mag	-0.9999995e9	PHOT_MAG
brPsfMagErr	[nspid]Source	WSA NonSurvey	Error in point source profile-fitted Br mag	real	4	mag	-0.9999995e9	ERROR
brSeqNum	[nspid]Source	WSA NonSurvey	the running number of the Br detection	int	4		-99999999	ID_NUMBER
brSerMag2D	[nspid]Source	WSA NonSurvey	Extended source Br mag (profile-fitted)	real	4	mag	-0.9999995e9	PHOT_MAG
brSerMag2DErr	[nspid]Source	WSA NonSurvey	Error in extended source Br mag (profile-fitted)	real	4	mag	-0.9999995e9	ERROR
brXi	[nspid]Source	WSA NonSurvey	Offset of Br 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.