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nonSurvey ** Announcement - Workshop: Science from UKIDSS II, 15-17 Dec 2008, London UK ** |
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Glossary of WSA attributes |
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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 |
Y | ||||||||
|---|---|---|---|---|---|---|---|---|
| Name | Schema Table | Database | Description | Type | Length | Unit | Default Value | Unified Content Descriptor |
| y | dxsDetection, dxsListRemeasurement, gcsDetection, gcsListRemeasurement, gpsDetection, gpsListRemeasurement, lasDetection, lasListRemeasurement, udsDetection, udsListRemeasurement | WSA | Y coordinate of detection {catalogue TType keyword: Y_coordinate} Intensity-weighted isophotal centre-of-gravity in Y. |
real | 4 | pixels | POS_PLATE_Y | |
| y_coadd | twomass_xsc | 2MASS | y (in-scan) position (coadd coord.). | real | 4 | arcsec | INST_POS | |
| yAperMag3 | gcsSource, lasSource | WSA | 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 |
| yAperMag3Err | gcsSource, lasSource | WSA | Error in default point/extended source Y mag (2.0 arcsec aperture diameter) | real | 4 | mag | -0.9999995e9 | ERROR |
| yAperMag4 | gcsSource, lasSource | WSA | Extended source Y aperture corrected mag (2.8 arcsec aperture diameter) | real | 4 | mag | -0.9999995e9 | PHOT_MAG |
| yAperMag4Err | gcsSource, lasSource | WSA | Error in extended source Y mag (2.8 arcsec aperture diameter) | real | 4 | mag | -0.9999995e9 | ERROR |
| yAperMag6 | gcsSource, lasSource | WSA | Extended source Y aperture corrected mag (5.7 arcsec aperture diameter) | real | 4 | mag | -0.9999995e9 | PHOT_MAG |
| yAperMag6Err | gcsSource, lasSource | WSA | Error in extended source Y mag (5.7 arcsec aperture diameter) | real | 4 | mag | -0.9999995e9 | ERROR |
| yCen | Detection | SSA | Intensity-weighted Y-centroid of image | float | 8 | microns | POS_PLATE_Y | |
| yClass | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | discrete image classification flag in Y | smallint | 2 | -9999 | CLASS_MISC | |
| yClassStat | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | N(0,1) stellarness-of-profile statistic in Y | real | 4 | -0.9999995e9 | STAT_PROP | |
| yDeblend | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | flag indicating parent/child relation in Y | int | 4 | -99999999 | CODE_MISC | |
| yEll | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | 1-b/a, where a/b=semi-major/minor axes in Y | real | 4 | -0.9999995e9 | PHYS_ELLIPTICITY | |
| yeNum | gcsMergeLog, lasMergeLog | WSA | the extension number of this Y frame | tinyint | 1 | NUMBER | ||
| yErr | dxsDetection, dxsListRemeasurement, gcsDetection, gcsListRemeasurement, gpsDetection, gpsListRemeasurement, lasDetection, lasListRemeasurement, udsDetection, udsListRemeasurement | WSA | Error in Y coordinate {catalogue TType keyword: Y_coordinate_err} Estimate of centroid error. |
real | 4 | pixels | ERROR | |
| yErrBits | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | processing warning/error bitwise flags in Y | int | 4 | -99999999 | CODE_MISC | |
| yEta | gcsSource, lasSource | WSA | Offset of Y detection from master position (+north/-south) | real | 4 | arcsec | -0.9999995e9 | POS_EQ_DEC_OFF |
| When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 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. | ||||||||
| yGausig | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | RMS of axes of ellipse fit in Y | real | 4 | pixels | -0.9999995e9 | MORPH_PARAM |
| yHallMag | gcsSource, lasSource | WSA | Total point source Y mag | real | 4 | mag | -0.9999995e9 | PHOT_MAG |
| yHallMagErr | gcsSource, lasSource | WSA | Error in total point source Y mag | real | 4 | mag | -0.9999995e9 | ERROR |
| yMag | CurrentStdStarInfo, PreviousStdStarInfo | WSA | Y band total magnitude of star (from external sources if primary) | real | 4 | mag | PHOT_INT-MAG | |
| yMag | gcsSourceRemeasurement, lasSourceRemeasurement | WSA | Y mag (as appropriate for this merged source) | real | 4 | mag | -0.9999995e9 | PHOT_MAG |
| yMagErr | CurrentStdStarInfo, PreviousStdStarInfo | WSA | Y band magnitude error of star | real | 4 | mag | ERROR | |
| yMagErr | gcsSourceRemeasurement, lasSourceRemeasurement | WSA | Error in Y mag | real | 4 | mag | -0.9999995e9 | ERROR |
| ymax | Detection | SSA | Topmost extent of image on plate | float | 8 | microns | POS_PLATE_Y | |
| ymfID | gcsMergeLog, lasMergeLog | WSA | the UID of the relevant Y multiframe | bigint | 8 | ID_FRAME | ||
| ymin | Detection | SSA | Bottommost extent of image on plate | float | 8 | microns | POS_PLATE_Y | |
| ymj | gcsSourceRemeasurement, lasSourceRemeasurement | WSA | Default colour Y-J (using appropriate mags) | real | 4 | mag | PHOT_COLOR | |
| ymj_1Ext | lasSource | WSA | Extended source colour Y-J (using aperMag3) | real | 4 | mag | -0.9999995e9 | PHOT_COLOR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| ymj_1ExtErr | lasSource | WSA | Error on extended source colour Y-J | real | 4 | mag | -0.9999995e9 | ERROR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| ymj_1Pnt | lasSource | WSA | Point source colour Y-J (using aperMag3) | real | 4 | mag | -0.9999995e9 | PHOT_COLOR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| ymj_1PntErr | lasSource | WSA | Error on point source colour Y-J | real | 4 | mag | -0.9999995e9 | ERROR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| ymjErr | gcsSourceRemeasurement, lasSourceRemeasurement | WSA | Error on colour Y-J | real | 4 | mag | ERROR | |
| ymjExt | gcsSource | WSA | Extended source colour Y-J (using aperMag3) | real | 4 | mag | -0.9999995e9 | PHOT_COLOR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| ymjExtErr | gcsSource | WSA | Error on extended source colour Y-J | real | 4 | mag | -0.9999995e9 | ERROR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| ymjPnt | gcsSource | WSA | Point source colour Y-J (using aperMag3) | real | 4 | mag | -0.9999995e9 | PHOT_COLOR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| ymjPntErr | gcsSource | WSA | Error on point source colour Y-J | real | 4 | mag | -0.9999995e9 | ERROR |
| Default colours from pairs of adjacent passbands within a given set (e.g. Y-J, J-H and H-K for YJHK) are recorded in the merged source table for ease of querying and speedy querying via indexing of these attributes. Presently, the point-source colours and extended source colours are computed from the aperture corrected AperMag3 fixed 2 arcsec aperture diameter measures (for consistent measurement across all passbands) and generally good signal-to-noise. At some point in the future, this may be changed such that point-source colours will be computed from the PSF-fitted measures and extended source colours computed from the 2-d Sersic model profile fits. | ||||||||
| yObjID | gcsSource, lasSource | WSA | the UID of the Y detection | bigint | 8 | -99999999 | ID_NUMBER | |
| yObjID | gcsSourceRemeasurement, lasSourceRemeasurement | WSA | the UID of the Y remeasurement | bigint | 8 | -99999999 | ID_NUMBER | |
| yPA | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | ellipse fit celestial orientation in Y | real | 4 | Degrees | -0.9999995e9 | POS_POS-ANG |
| yPetroMag | gcsSource, lasSource | WSA | Extended source Y mag (Petrosian) | real | 4 | mag | -0.9999995e9 | PHOT_MAG |
| yPetroMagErr | gcsSource, lasSource | WSA | Error in extended source Y mag (Petrosian) | real | 4 | mag | -0.9999995e9 | ERROR |
| yPixSize | CurrentAstrometry, PreviousAstrometry | WSA | Angular size of pixels in Y | real | 4 | Arcseconds | -0.9999995e9 | POS_ANG_DIST_GENERAL |
| yPnt | Plate | SSA | Centre of scan area in Y | real | 4 | microns | POS_PLATE_Y | |
| yppErrBits | gcsSource, gcsSourceRemeasurement, lasSource, lasSourceRemeasurement | WSA | additional WFAU post-processing error bits in Y | int | 4 | 0 | CODE_MISC | |
| yPsfMag | gcsSource, lasSource | WSA | Point source profile-fitted Y mag | real | 4 | mag | -0.9999995e9 | PHOT_MAG |
| yPsfMagErr | gcsSource, lasSource | WSA | Error in point source profile-fitted Y mag | real | 4 | mag | -0.9999995e9 | ERROR |
| ySeqNum | gcsSource, lasSource | WSA | the running number of the Y detection | int | 4 | -99999999 | ID_NUMBER | |
| ySeqNum | gcsSourceRemeasurement, lasSourceRemeasurement | WSA | the running number of the Y remeasurement | int | 4 | -99999999 | ID_NUMBER | |
| ySerMag2D | gcsSource, lasSource | WSA | Extended source Y mag (profile-fitted) | real | 4 | mag | -0.9999995e9 | PHOT_MAG |
| ySerMag2DErr | gcsSource, lasSource | WSA | Error in extended source Y mag (profile-fitted) | real | 4 | mag | -0.9999995e9 | ERROR |
| ySize | MultiframeDetector | WSA | Corresponding image size (Y); value only available if catalogue file exists {catalogue extension keyword: NYOUT} | int | 4 | -99999999 | NUMBER | |
| yXi | gcsSource, lasSource | WSA | Offset of Y detection from master position (+east/-west) | real | 4 | arcsec | -0.9999995e9 | POS_EQ_RA_OFF |
| When associating individual passband detections into merged sources, a generous (in terms of the positional uncertainties) pairing radius of 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. | ||||||||