II/284 COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)
The first release COSMOS optical and Near-IR data and catalog.
Capak P., Aussel H., Ajiki M., McCracken H.J., Mobasher B., Scoville N.,
Shopbell P., Taniguchi Y., Thompson D., Tribiano S., Sasaki S., Blain A.W.,
Brusa M., Carilli C., Comastri A., Carollo C.M., Cassata P., Colbert J.,
Ellis R.S., Elvis M., Giavalisco M., Green W., Guzzo L., Hasinger G.,
Ilbert O., Impey C., Jahnke K., Kartaltepe J., Kneib J.-P., Koda J.,
Koekemoer A., Komiyama Y., Leauthaud A., Lefevre O., Lilly S., Liu C.,
Massey R., Miyazaki S., Murayama T., Nagao T., Peacock J.A., Pickles A.,
Porciani C., Renzini A., Rhodes J., Rich M., Salvato M., Sanders D.B.,
Scarlata C., Schiminovich D., Schinnerer E., Scodeggio M., Sheth K.,
Shioya Y., Tasca L.A.M., Taylor J.E., Yan L., Zamorani G.
<Astrophys. J. Suppl. Ser., 172, 99-116 (2007)>
=2007ApJS..172...99C 2007ApJS..172...99C
ADC_Keywords: Surveys ; Photometry, UBV ; Photometry, SDSS ; Photometry, HST
Keywords: cosmology: observations - galaxies: evolution -
large-scale structure of universe - surveys
Abstract:
We present imaging data and photometry for the COSMOS survey in 15
photometric bands between 0.3 and 2.4m. These include data taken on
the Subaru 8.3m telescope, the KPNO and CTIO 4m telescopes, and the
CFHT 3.6m telescope. Special techniques are used to ensure that the
relative photometric calibration is better than 1% across the field of
view. The absolute photometric accuracy from standard-star
measurements is found to be 6%. The absolute calibration is corrected
using galaxy spectra, providing colors accurate to 2% or better.
Stellar and galaxy colors and counts agree well with the expected
values. Finally, as the first step in the scientific analysis of these
data we construct panchromatic number counts which confirm that both
the geometry of the universe and the galaxy population are evolving.
Description:
The present COSMOS data were collected on a variety of telescopes and
instruments, as well as from the Sloan Digital Sky Survey (SDSS)
second data release (DR2) archive (u, g, r, i, z) and Hubble Space
Telescope (HST, F814W). This paper covers the processing of the data
obtained with Suprime-Cam on the Subaru 8.3m telescope (Bj, Vj, g+,
r+, i+, z+, NB816), Megaprime on the 3.6m Canada-France-Hawaii
Telescope (CFHT, u*, i*), FLAMINGOS on the Kitt Peak National
Observatory (KPNO, Ks) 4m telescope, and the Infrared Side Port Imager
on the Cerro Tololo Inter-American Observatory (CTIO, Ks) 4m telescope
during the 2004-2005 observing season.
The COSMOS I band catalog is an I band selected multi-color catalog
for 2 square degrees centered on the COSMOS field at 10:00:28.6,
+02:12:21.
The total magnitude (SExtractor mag_auto) for a source must have an
AB magnitude of less than i+<25 to appear in the archival catalog.
All photometry is in the AB magnitude system and measured in a 3"
aperture on PSF-matched images unless otherwise noted. A magnitude of
-99 indicates a photometric measurement was not possible due to lack
of data, a large number of bad pixels, or saturation. A magnitude of
99.0 indicates no detection. In the case of no detection the error
given for the object is the 1 sigma limiting magnitude at the position
of the source.
The photometry is as measured on the images with no corrections
applied. We recommend applying the magnitude offsets in the paper
to obtain the best possible photometry. More details on the photometry
are available in the paper. The Photometric Redshifts included in this
catalog are described in Mobasher et al. (2007ApJS..172..117M 2007ApJS..172..117M) and
have an accuracy of dz/(1+z)<0.031 at z<1.2 and I<24.
It is important to pay attention to the flag columns at the end of the
catalog. The cleanest catalog will have all flags set to 0. The
photometry flags indicate the area of the photometry aperture, in
square arc seconds, which is in a masked region. A flag of 1 indicates
14 percent of the aperture is masked, so any flagged object should be
carefully checked. Objects with a de-blending flag set to 1 are
potentially spurious and should not be used for statistical studies.
However, the photometry for real sources with a de-blending flag set
to 1 is good if they fall outside of masked region.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cosmos.dat 473 438226 COSMOS Multi-Wavelength Photometry Catalog
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See also:
http://www.sdss.org/ : SDSS Home Page
J/AJ/127/180 : The Hawaii Hubble Deep Field North (Capak+, 2004)
Byte-by-byte Description of file: cosmos.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- COSMOS Unique identification number of each source
in the catalog
9- 11 I3 --- Image [1/144] Which of the 144 sub-image tiles
contains this object
13- 21 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000.0)
22- 30 F9.5 deg DEdeg Declination in decimal degrees (J2000.0)
32- 39 F8.3 pix Xpix X pixel position on the sub-image tile
41- 48 F8.3 pix Ypix Y pixel position on the sub-image tile
50- 55 F6.2 pix ifwhm ?=-99 FWHM measured on the detection image
indicated by n_imagA
57- 68 F12.6 uJy imax ?=-99 Peak flux measured on the detection
image indicated by n_imagA
70- 75 F6.2 --- istar ?=-99 SExtractor stellarity parameter measured
on the detection image indicated by n_imagA
77- 84 F8.4 mag imagA ?=-99 Total i-band magnitude measured on the
detection image indicated by n_imagA
86- 93 F8.4 mag dmag3 ?=-99 Offset between 3" aperture magnitudes
and the total magnitude. This is the
aperture correction for the multi-color
photometry
95- 96 I2 --- n_imagA [-1/2] Flag indicating which image the total
magnitude (imagA) was measured (1)
98-105 F8.4 mag umag ?=-99. CFHT u* AB magnitude (8)
107-114 F8.4 mag e_umag ?=-99. 1 Sigma error on CFHT umag (9)
116-123 F8.4 mag Bmag ?=-99. Subaru Bj AB magnitude (8)
125-132 F8.4 mag e_Bmag ?=-99. 1 Sigma error on Subaru Bmag (9)
134-141 F8.4 mag Vmag ?=-99. Subaru Vj AB magnitude (8)
143-150 F8.4 mag e_Vmag ?=-99. 1 Sigma error on Subaru Vmag (9)
152-159 F8.4 mag gmag ?=-99. Subaru g+ AB magnitude (8)
161-168 F8.4 mag e_gmag ?=-99. 1 Sigma error on Subaru gmag (9)
170-177 F8.4 mag rmag ?=-99. Subaru r+ AB magnitude (8)
179-186 F8.4 mag e_rmag ?=-99. 1 Sigma error on Subaru rmag (9)
188-195 F8.4 mag imag ?=-99. Subaru i+ AB magnitude (8)
197-204 F8.4 mag e_imag ?=-99. 1 Sigma error on Subaru imag (9)
206-213 F8.4 mag zmag ?=-99. Subaru z+ AB magnitude (8)
215-222 F8.4 mag e_zmag ?=-99. 1 Sigma error on Subaru zmag (9)
224-231 F8.4 mag Kmag ?=-99. CTIO/KPNO Ks AB magnitude (8)
233-240 F8.4 mag e_Kmag ?=-99. 1 Sigma error on CTIO/KPNO Kmag (9)
242-249 F8.4 mag iCFHT ?=-99. CFHT i* AB magnitude (8)
251-258 F8.4 mag e_iCFHT ?=-99. 1 Sigma error on CFHT imag (9)
260-267 F8.4 mag uSDSS ?=-99. SDSS u AB magnitude (8)
269-276 F8.4 mag e_uSDSS ?=-99. 1 Sigma error on SDSS umag (9)
278-285 F8.4 mag gSDSS ?=-99. SDSS g AB magnitude (8)
287-294 F8.4 mag e_gSDSS ?=-99. 1 Sigma error on SDSS gmag (9)
296-303 F8.4 mag rSDSS ?=-99. SDSS r AB magnitude (8)
305-312 F8.4 mag e_rSDSS ?=-99. 1 Sigma error on SDSS rmag (9)
314-321 F8.4 mag iSDSS ?=-99. SDSS i AB magnitude (8)
323-330 F8.4 mag e_iSDSS ?=-99. 1 Sigma error on SDSS imag (9)
332-339 F8.4 mag zSDSS ?=-99. SDSS z AB magnitude (8)
341-348 F8.4 mag e_zSDSS ?=-99. 1 Sigma error on SDSS zmag (9)
350-357 F8.4 mag F814W ?=-99. HST F814W magnitude (8)
359-366 F8.4 mag e_F814W ?=-99. 1 Sigma error on HST F814W mag (9)
368-375 F8.4 mag NB816 ?=-99. Subaru NB816 magnitude (8)
377-384 F8.4 mag e_NB816 ?=-99. 1 Sigma error on Subaru NB816 mag (9)
386-393 F8.6 mag E(B-V) E(B-V) for this object position from
Schlegel et al. (1998ApJ...500..525S 1998ApJ...500..525S)
395-398 F4.2 --- zphot Photometric Redshift from Mobasher et al.
(2007ApJS..172..117M 2007ApJS..172..117M)
400-403 F4.2 --- z68min Minimum photometric redshift at 68% probability
405-408 F4.2 --- z68max Maximum photometric redshift at 68% probability
410-413 F4.2 --- z95min Minimum photometric redshift at 95% probability
415-418 F4.2 --- z95max Maximum photometric redshift at 95% probability
420-423 F4.2 --- Tphot [1/6] Photometric type of the object (2)
425-428 F4.2 mag Rphot ?=0 Intrinsic e(B-V) of the object estimated
by the photometric redshift code (3)
430-435 F6.2 --- Chi2 Chi-square of best fit redshift and
photometric type
437-438 I2 --- Nf Number of filters used for in the
photometric redshift estimation
440-447 F8.3 mag VMAG Absolute V band AB magnitude
449-453 F5.3 --- D95 D95 parameter (4)
455-461 F7.3 [solMass] logMass Log base 10 of the stellar mass (3)
463 I1 --- Star [0/1] Star flag based on color and
morphology, 0=Non-Star and 1=Star (5)
465 I1 --- BMask Bj image mask (6)
467 I1 --- VMask Vj image mask (6)
469 I1 --- iMask i+ image mask (6)
471 I1 --- zMask z+ image mask (6)
473 I1 --- blFlag [0/1] de-blended or false detection (7)
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Note (1): Flag for the total magnitude measurement as follows:
1 = Subaru i+
2 = CFHT i*
-1 = No valid total magnitude
Note (2): Photometric type of the object as described in Mobasher et al.
(2007ApJS..172..117M 2007ApJS..172..117M):
1 = El;
2 = Sbc;
3 = Scd;
4 = Irr;
5 = SB3;
6 = SB2.
Non integer values indicate a type between the integer types.
Note (3): See Mobasher et al. (2007ApJS..172..117M 2007ApJS..172..117M) for details.
Note (4): D95 parameter from Mobasher et al. (2007ApJS..172..117M 2007ApJS..172..117M) defined
as the ratio of the 95% confidence interval to the best fit redshift.
Note (5): From Capak et al. (2007, Cat. J/AJ/127/180).
Note (6): Area of the photometry aperture in square arcseconds which falls
into a masked area on the image. Please refer to the text above in
the "Description" section for more information on masks and flags.
Note (7): 0 indicates a good detection;
a value of 1 indicates a problematic detection, see Capak et al.
(2007, Cat. J/AJ/127/180) for details.
Note (8): 99. or -99. when no data.
Filter Subaru NB816: λc=8154Å, Δλ(FWHM)=120Å
Note (9): Value>20 indicates no measurements.
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History:
Copied at http://irsa.ipac.caltech.edu/data/COSMOS/
(End) Patricia Vannier [CDS] 03-Mar-2008