II/314 UKIDSS-DR8 LAS, GCS and DXS Surveys (Lawrence+ 2012)
UKIRT Infrared Deep Sky Survey (UKIDSS) Release 8
Lawrence A., Warren S.J., Almaini O., Edge A.C., Hambly N.C., Jameson R.F.,
Lucas P., Casali M., Adamson A., Dye S., Emerson J.P., Foucaud S.,
Hewett P., Hirst P., Hodgkin S.T., Irwin M.J., Lodieu N., McMahon R.G.,
Simpson C., Smail I., Mortlock D., Folger M.
<Mon. Not. R. Astron. Soc. 379, 1599 (2007)>
=2007MNRAS.379.1599L 2007MNRAS.379.1599L
=2012yCat.2314....0U 2012yCat.2314....0U
ADC_Keywords: Surveys ; Infrared sources ; Photometry, infrared
Keywords: surveys - infrared: general
Description:
The UKIRT Infrared Deep Sky Survey (UKIDSS) is a large-scale near-IR
survey which aim is to cover 7500 square degrees of the Northern sky.
The survey is carried out using the Wide Field Camera (WFCAM), with a
field of view of 0.21 square degrees, mounted on the 3.8m United
Kingdom Infra-red Telescope (UKIRT) in Hawaii. The project comprises
five surveys (LAS, GCS, DXS, GPS and UDS).
The Large Area Survey (LAS) covers an area of 4000 square degrees in
high Galactic latitudes (extragalactic) in the four bands Y(1.0um)
J(1.2um) H(1.6um) and K(2.2um) to a depth of K=18.4.
The Galactic Clusters Survey (GCS) aims to survey ten large open star
clusters and star formation associations, covering a total of 1067
square degrees in the five bands Z (0.9um), Y(1.0um) J(1.2um) H(1.6um)
and K(2.2um), plus a second pass in K for proper motions, to a depth
of Z=20.4, Y=20.3, J=19.5, H=18.6, K=18.6.
The Deep Extragalactic Survey (DXS) aims to map 35 square degrees of
sky to a 5-σ point-source sensitivity of J=22.3 and K=20.8 in
four carefully selected, multi-wavelength survey areas. The central
regions of each field will also be mapped to H=21.8. The primary aim
of the survey is to produce a photometric galaxy sample at a redshift
of 1-2, within a volume comparable to that of the SDSS, selected in
the same passband (rest frame optical).
Details of the surveys can be found in the in the paper by Lawrence
et al. (2007MNRAS.379.1599L 2007MNRAS.379.1599L), and at the UKIDSS Surveys site
(http://www.ukidss.org/surveys/surveys.html). The data described here
represent a subset of the UKIDSS data, limited to the public data and
most representative columns. In the "Byte-by-byte Description" below
the original names of the columns are given as bracketed names.
Usage of the UKIDSS data:
All users of UKIDSS data should include an acknowledgement in their
publications as follows: "This work is based in part on data obtained
as part of the UKIRT Infrared Deep Sky Survey".
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
las8.sam 451 1000 Sample of the UKIDSS-DR8 Large Area Survey
(total of 69,656,413 sources)
gcs8.sam 540 1000 Sample of the UKIDSS-DR8 Galactic Clusters Survey
(total of 51,047,570 sources)
dxs8.sam 268 1000 Sample of the UKIDSS-DR8 Deep Extragalactic Survey
(total of 2,042,339 sources)
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See also:
http://www.ukidss.org/surveys/surveys.html : UKIDSS Surveys
http://surveys.roe.ac.uk/wsa/dr8plus_release.html : UKIDSS-DR8 Release
II/316 : UKIDSS-DR6 Galactic Plane Survey (GPS) (Lucas+ 2012)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: las8.sam
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Bytes Format Units Label Explanations
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1- 19 A19 --- ULAS Name of source in survey (G5)
21- 30 F10.6 deg RAdeg Right ascension (J2000)
32- 41 F10.6 deg DEdeg Declination (J2000)
44- 49 F6.3 mag Ymag ? UKIDSS Y default magnitude (yAperMag3) (G1)
51- 56 F6.3 mag Jmag ? UKIDSS J default magnitude (j_1AperMag3) (G1)
58- 63 F6.3 mag Hmag ? UKIDSS H default magnitude ( hAperMag3) (G1)
65- 70 F6.3 mag Kmag ? UKIDSS K default magnitude (kAperMag3) (G1)
73- 78 F6.3 mag e_Ymag ? Mean error on Ymag (yAperMag3Err)
80- 85 F6.3 mag e_Jmag ? Mean error on Jmag (j_1AperMag3Err)
87- 92 F6.3 mag e_Hmag ? Mean error on Hmag (hAperMag3Err)
94- 99 F6.3 mag e_Kmag ? Mean error on Kmag (kAperMag3Err)
101-112 A12 --- ID Unique ID of this merged detection (sourceID)
114 I1 --- m [1/2] "2" indicates a duplicated source (G6)
116-124 F9.4 yr Epoch Epoch of position measurement (epoch)
126-127 I2 --- nf Number of frames (nFrames)
130-135 F6.2 --- mStat Merged profile class statistic (mergedClassStat)
137-138 I2 --- cl [-3,1] Merged source class (mergedClass) (G2)
140-143 F4.2 --- p* [0,1] Probability of being a star (pStar)
145-148 F4.2 --- pG [0,1] Probability of being a galaxy (pGalaxy)
150-153 F4.2 --- pN [0,1] Probability of being noise (pNoise)
--------------------------------------------------------------------------------
156-161 F6.3 mag Ytot ? Total point source Y magnitude (yHallMag)
163-168 F6.3 mag e_Ytot ? Mean error on Ytot (yHallMagErr)
170-175 F6.3 mag pYmag ? Petrosian Y magnitude (yPetroMag)
177-182 F6.3 mag e_pYmag ? Mean error on pYmag (yPetroMagErr)
184-191 F8.3 pix Ydiam ? Y-band RMS of axes of ellipse fit (yGausig)
193-196 F4.2 --- Yell [0,1]? Source ellipticity in Y-band (yEll)
198-202 F5.1 deg Ypa [0,180]? Position angle of Y-band ellipse (yPA)
204-206 I3 --- Ybad Y-band zero confidence pixels (yErrBits) (G3)
208-209 I2 --- Ycl [-3,1]? Y-band source class (yClass) (G2)
211-217 I7 --- Yflags [0,8388607]? Y-band flags (yppErrBits) (G4)
--------------------------------------------------------------------------------
220-225 F6.3 mag Jtot ? Total point source J magnitude (j_1HallMag)
227-232 F6.3 mag e_Jtot ? Mean error on Jtot (j_1HallMagErr)
234-239 F6.3 mag pJmag ? Petrosian J magnitude (j_1PetroMag)
241-246 F6.3 mag e_pJmag ? Mean error on pJmag (j_1PetroMagErr)
248-255 F8.3 pix Jdiam ? J-band RMS of axes of ellipse fit (j_1Gausig)
257-260 F4.2 --- Jell [0/1]? J-band ellipticity (G1-b/a) (j_1Ell)
262-266 F5.1 deg Jpa [0,180]? J-band position angle (j_1PA)
268-270 I3 --- Jbad J-band zero confidence pixels (j_1ErrBits) (G3)
272-273 I2 --- Jcl [-3,1]? J-band source class (j_1Class) (G2)
275-281 I7 --- Jflags [0,8388607] J-band flags (j_1ppErrBits) (G4)
283-288 F6.3 arcsec Jdx ? ξ offset to Y-band source (j_1Xi)
290-295 F6.3 arcsec Jdy ? η offset to Y-band source (j_1Eta)
--------------------------------------------------------------------------------
298-303 F6.3 mag Htot ? Total point source H magnitude (hHallMag)
305-310 F6.3 mag e_Htot ? Mean error on Htot (hHallMagErr)
312-317 F6.3 mag pHmag ? Petrosian H magnitude (hPetroMag)
319-324 F6.3 mag e_pHmag ? Mean error on Hpag (hPetroMagErr)
326-333 F8.3 pix Hdiam ? RMS of axes of ellipse fit in H-band (hGausig)
335-338 F4.2 --- Hell ? Ellipticity in H-band (hEll)
340-344 F5.1 deg Hpa [0,180]? H-band position angle (hPA)
346-348 I3 --- Hbad H-band zero confidence pixels (hErrBits) (G3)
350-351 I2 --- Hcl [-3,1] H-band source class (hClass) (G2)
353-359 I7 --- Hflags [0,8388607] flags (hppErrBits) (G4)
361-366 F6.3 arcsec Hdx ? ξ offset to Y-band source (hXi)
368-373 F6.3 arcsec Hdy ? η offset to Y-band source (hEta)
--------------------------------------------------------------------------------
376-381 F6.3 mag Ktot ? Total point source K magnitude (kHallMag)
383-388 F6.3 mag e_Ktot ? Mean error on Ktot (kHallMagErr)
390-395 F6.3 mag pKmag ? Petrosian K magnitude (kPetroMag)
397-402 F6.3 mag e_pKmag ? Mean error on pKmag (kPetroMagErr)
404-411 F8.3 pix Kdiam ? RMS of axes of ellipse fit in K-band (kGausig)
413-416 F4.2 --- Kell ? K-band ellipticity (kEll)
418-422 F5.1 deg Kpa [0,180]? K-band position angle (kPA)
424-426 I3 --- Kbad K-band zero confidence pixels (kErrBits) (G3)
428-429 I2 --- Kcl [-3,1] K-band source class (kClass) (G2)
431-437 I7 --- Kflags [0,8388607] flags (kppErrBits) (G4)
439-444 F6.3 arcsec Kdx ? ξ offset to Y-band source (kXi)
446-451 F6.3 arcsec Kdy ? η offset to Y-band source (kEta)
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Byte-by-byte Description of file: gcs8.sam
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- UGCS Name of source in survey (G5)
21- 30 F10.6 deg RAdeg Right ascension (J2000)
32- 41 F10.6 deg DEdeg Declination (J2000)
44- 49 F6.3 mag Zmag ? UKIDSS Z default magnitude (zAperMag3) (G1)
51- 56 F6.3 mag Ymag ? UKIDSS Y default magnitude (yAperMag3) (G1)
58- 63 F6.3 mag Jmag ? UKIDSS J default magnitude (jAperMag3) (G1)
65- 70 F6.3 mag Hmag ? UKIDSS H default magnitude (hAperMag3) (G1)
72- 77 F6.3 mag Kmag ? UKIDSS K default magnitude (k_1AperMag3) (G1)
80- 85 F6.3 mag e_Zmag ? Mean error on Zmag (zAperMag3Err)
87- 92 F6.3 mag e_Ymag ? Mean error on Ymag (yAperMag3Err)
94- 99 F6.3 mag e_Jmag ? Mean error on Jmag (jAperMag3Err)
101-106 F6.3 mag e_Hmag ? Mean error on Hmag (hAperMag3Err)
108-113 F6.3 mag e_Kmag ? Mean error on Kmag (k_1AperMag3Err)
115-126 A12 --- ID Unique ID of this merged detection (sourceID)
128 I1 --- m [1/2] "2" indicates a duplicated source (G6)
130-138 F9.4 yr Epoch Epoch of position measurement (epoch)
141-146 F6.2 --- mStat Merged profile class statistic (mergedClassStat)
148-149 I2 --- cl [-3,1] Merged source class (mergedClass) (G2)
151-154 F4.2 --- p* [0,1] Probability of being a star (pStar)
156-159 F4.2 --- pG [0,1] Probability of being a galaxy (pGalaxy)
161-164 F4.2 --- pN [0,1] Probability of being noise (pNoise)
--------------------------------------------------------------------------------
167-172 F6.3 mag Ztot ? Total point source Z magnitude (zHallMag)
174-179 F6.3 mag e_Ztot ? Mean error on Ztot (zHallMagErr)
181-186 F6.3 mag pZmag ? Petrosian Z magnitude (zPetroMag)
188-193 F6.3 mag e_pZmag ? Mean error on pZmag (zPetroMagErr)
195-202 F8.3 pix Zdiam ? Z-band RMS of axes of ellipse fit (zGausig)
204-207 F4.2 --- Zell [0,1]? Source ellipticity in Z-band (zEll)
209-213 F5.1 deg Zpa [0,180]? Position angle of Z-band ellipse (zPA)
215-217 I3 --- Zbad Z-band zero confidence pixels (zErrBits) (G3)
219-220 I2 --- Zcl [-3,1]? Z-band source class (zClass) (G2)
222-228 I7 --- Zflags [0,8388607]? Z-band flags (zppErrBits) (G4)
--------------------------------------------------------------------------------
231-236 F6.3 mag Ytot ? Total point source Y magnitude (yHallMag)
238-243 F6.3 mag e_Ytot ? Mean error on Ytot (yHallMagErr)
245-250 F6.3 mag pYmag ? Petrosian Y magnitude (yPetroMag)
252-257 F6.3 mag e_pYmag ? Mean error on pYmag (yPetroMagErr)
259-266 F8.3 pix Ydiam ? Y-band RMS of axes of ellipse fit (yGausig)
268-271 F4.2 --- Yell [0,1]? Source ellipticity in Y-band (yEll)
273-277 F5.1 deg Ypa [0,180]? Position angle of Y-band ellipse (yPA)
279-281 I3 --- Ybad Y-band zero confidence pixels (yErrBits) (G3)
283-284 I2 --- Ycl [-3,1]? Y-band source class (yClass) (G2)
286-292 I7 --- Yflags [0,8388607]? Y-band flags (yppErrBits) (G4)
294-299 F6.3 arcsec Ydx ? ξ offset to Z-band source (yXi)
301-306 F6.3 arcsec Ydy ? η offset to Z-band source (yEta)
--------------------------------------------------------------------------------
309-314 F6.3 mag Jtot ? Total point source J magnitude (jHallMag)
316-321 F6.3 mag e_Jtot ? Mean error on Jtot (jHallMagErr)
323-328 F6.3 mag pJmag ? Petrosian J magnitude (jPetroMag)
330-335 F6.3 mag e_pJmag ? Mean error on pJmag (jPetroMagErr)
337-344 F8.3 pix Jdiam ? J-band RMS of axes of ellipse fit (jGausig)
346-349 F4.2 --- Jell [0/1]? J-band ellipticity (1-b/a) (jEll)
351-355 F5.1 deg Jpa [0,180]? J-band position angle (jPA)
357-359 I3 --- Jbad J-band zero confidence pixels (jErrBits) (G3)
361-362 I2 --- Jcl [-3,1]? J-band source class (jClass) (G2)
364-370 I7 --- Jflags [0,8388607] J-band flags (jppErrBits) (G4)
372-377 F6.3 arcsec Jdx ? ξ offset to Z-band source (jXi)
379-384 F6.3 arcsec Jdy ? η offset to Z-band source (jEta)
--------------------------------------------------------------------------------
387-392 F6.3 mag Htot ? Total point source H magnitude (hHallMag)
394-399 F6.3 mag e_Htot ? Mean error on Htot (hHallMagErr)
401-406 F6.3 mag pHmag ? Petrosian H magnitude (hPetroMag)
408-413 F6.3 mag e_pHmag ? Mean error on Hpag (hPetroMagErr)
415-422 F8.3 pix Hdiam ? H-band RMS of axes of ellipse fit (hGausig)
424-427 F4.2 --- Hell ? Ellipticity in H-band (hEll)
429-433 F5.1 deg Hpa [0,180]? H-band position angle (hPA)
435-437 I3 --- Hbad H-band zero confidence pixels (hErrBits) (G3)
439-440 I2 --- Hcl [-3,1] H-band source class (hClass) (G2)
442-448 I7 --- Hflags [0,8388607] flags (hppErrBits) (G4)
450-455 F6.3 arcsec Hdx ? ξ offset to Z-band source (hXi)
457-462 F6.3 arcsec Hdy ? η offset to Z-band source (hEta)
--------------------------------------------------------------------------------
465-470 F6.3 mag Ktot ? Total point source K magnitude (k_1HallMag)
472-477 F6.3 mag e_Ktot ? Mean error on Ktot (k_1HallMagErr)
479-484 F6.3 mag pKmag ? Petrosian K magnitude (k_1PetroMag)
486-491 F6.3 mag e_pKmag ? Mean error on pKmag (k_1PetroMagErr)
493-500 F8.3 pix Kdiam ? K-band RMS of axes of ellipse fit (k_1Gausig)
502-505 F4.2 --- Kell ? K-band ellipticity (k_1Ell)
507-511 F5.1 deg Kpa [0,180]? K-band position angle (k_1PA)
513-515 I3 --- Kbad K-band zero confidence pixels (k_1ErrBits) (G3)
517-518 I2 --- Kcl [-3,1] K-band source class (k_1Class) (G2)
520-526 I7 --- Kflags [0,8388607] flags (k_1ppErrBits) (G4)
528-533 F6.3 arcsec Kdx ? ξ offset to Z-band source (k_1Xi)
535-540 F6.3 arcsec Kdy ? η offset to Z-band source (k_1Eta)
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Byte-by-byte Description of file: dxs8.sam
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- UDXS Name of source in survey (G5)
21- 30 F10.6 deg RAdeg Right ascension (J2000)
32- 41 F10.6 deg DEdeg Declination (J2000)
44- 49 F6.3 mag Jmag ? UKIDSS J default magnitude (jAperMag3) (G1)
51- 56 F6.3 mag Kmag ? UKIDSS K default magnitude (k_1AperMag3) (G1)
59- 64 F6.3 mag e_Jmag ? Mean error on Jmag (jAperMag3Err)
66- 71 F6.3 mag e_Kmag ? Mean error on Kmag (k_1AperMag3Err)
--------------------------------------------------------------------------------
73- 84 A12 --- ID Unique ID of this merged detection (sourceID)
86 I1 --- m [1/2] "2" indicates a duplicated source (G6)
89- 94 F6.2 --- mStat Merged profile class statistic (mergedClassStat)
96- 97 I2 --- cl [-3,1] Merged source class (mergedClass) (G2)
99-102 F4.2 --- p* [0,1] Probability of being a star (pStar)
104-107 F4.2 --- pG [0,1] Probability of being a galaxy (pGalaxy)
109-112 F4.2 --- pN [0,1] Probability of being noise (pNoise)
--------------------------------------------------------------------------------
115-120 F6.3 mag Jtot ? Total point source J magnitude (jHallMag)
122-127 F6.3 mag e_Jtot ? Mean error on Jtot (jHallMagErr)
129-134 F6.3 mag pJmag ? Petrosian J magnitude (jPetroMag)
136-141 F6.3 mag e_pJmag ? Mean error on pJmag (jPetroMagErr)
143-150 F8.3 pix Jdiam ? J-band RMS of axes of ellipse fit (jGausig)
152-155 F4.2 --- Jell [0/1]? J-band ellipticity (1-b/a) (jEll)
157-161 F5.1 deg Jpa [0,180]? J-band position angle (jPA)
163-165 I3 --- Jbad J-band zero confidence pixels (jErrBits) (G3)
167-168 I2 --- Jcl [-3,1]? J-band source class (jClass) (G2)
170-176 I7 --- Jflags [0,8388607] J-band flags (jppErrBits) (G4)
178-183 F6.3 arcsec Jdx ? ξ East-offset to master detection (jXi)
185-190 F6.3 arcsec Jdy ? η North-offset to master detection (jEta)
--------------------------------------------------------------------------------
193-198 F6.3 mag Ktot ? Total point source K magnitude (kHallMag)
200-205 F6.3 mag e_Ktot ? Mean error on Ktot (kHallMagErr)
207-212 F6.3 mag pKmag ? Petrosian K magnitude (kPetroMag)
214-219 F6.3 mag e_pKmag ? Mean error on pKmag (kPetroMagErr)
221-228 F8.3 pix Kdiam ? K-band RMS of axes of ellipse fit (kGausig)
230-233 F4.2 --- Kell ? K-band ellipticity (kEll)
235-239 F5.1 deg Kpa [0,180]? K-band position angle (kPA)
241-243 I3 --- Kbad K-band zero confidence pixels (kErrBits) (G3)
245-246 I2 --- Kcl [-3,1] K-band source class (kClass) (G2)
248-254 I7 --- Kflags [0,8388607] flags (kppErrBits) (G4)
256-261 F6.3 arcsec Kdx ? ξ East-offset to master detection (kXi)
263-268 F6.3 arcsec Kdy ? η North-offset to master detection (kEta)
--------------------------------------------------------------------------------
Global Notes:
Note (G1): recommended magnitude, corrected from a 2.0arcsec aperture
diameter), valid for both point and extended sources.
The filters characteristics are (from Hewett et al. 2006MNRAS.367..454H 2006MNRAS.367..454H)
--------------------------
Z 0.882 ± 0.093 µm
Y 1.031 ± 0.102 µm
J 1.248 ± 0.159 µm
H 1.631 ± 0.292 µm
K 2.201 ± 0.351 µm
--------------------------
Note (G2): The profile classification takes the following values:
-3 = Probable galaxy (with a probability between 70 and 90%)
-2 = Probable star (with a probability between 70 and 90%)
-1 = Star (with a probability ≥ 90%)
0 = Noise (with a probability ≥ 90%)
+1 = Galaxy (with a probability ≥ 90%)
Note (G3): count of the number of zero confidence pixels in the default
(G2arcsec diameter) aperture.
Note (G4): the post-processing error bits are resumed in a number defined
as {Sum}2b, b being the bit number between 0 and 31.
The meaning of b's is as follows:
--------------------------------------------------------------------------
b decimal hexadecimal Meaning
--------------------------------------------------------------------------
2 4 0x00000004 Close to a bright source (not yet implemented)
4 16 0x00000010 Deblended
6 64 0x00000040 Bad pixel(s) in default aperture
15 32768 0x00008000 Source in poor flat field region
16 65536 0x00010000 Close to saturated
17 131072 0x00020000 Photometric calibration probably subject
to systematic error
19 524288 0x00080000 Possible crosstalk artefact/contamination
20 1048576 0x00100000 Possible diffraction spike contamination
22 4194304 0x00400000 Lies within a dither offset of the stacked
frame boundary
--------------------------------------------------------------------------
Note (G5): The correct designation for UKIDSS sources is formed from the
J2000 position truncated to 0.01s in right ascension and 0.1arcsec in
declination:
* ULAS JHHMMSS.ss+DDMMSS.s for the Large Area Survey;
* UGCS JHHMMSS.ss+DDMMSS.s for the Galactic Clusters Survey
* UDXS JHHMMSS.ss+DDMMSS.s for the Deep Extragalactic Survey
Note (G6):
This flag is derived from the original priOrSec and frameSetID attributes:
* m=1 if (priOrSec=0 OR priOrSec=frameSetID) : is a primary source
* m=2 if (priOrSec!=0 AND priOrSec!=frameSetID): the source has
a duplicate in another frameSet.
Acknowledgements:
It is a pleasure to thank Nigel Hambly, who helped in the preparation
of these catalogues.
(End) Francois Ochsenbein [CDS] 29-Mar-2012