J/ApJS/268/17 The Chandra X-ray Galaxy Catalog (CGC) (Kim+, 2023)
The Chandra Source Catalog Normal Galaxy Sample.
Kim D.-W., Cassity A., Bhatt B., Fabbiano G., Martinez Galarza J.R.,
O'Sullivan E., Rots A.
<Astrophys. J. Suppl. Ser., 268, 17 (2023)>
=2023ApJS..268...17K 2023ApJS..268...17K
ADC_Keywords: Galaxy catalogs; X-ray sources; Cross identifications;
Photometry, ugriz; Ultraviolet; Redshifts; Surveys
Keywords: Galaxies
Abstract:
We present the extensive and well-characterized Chandra X-ray Galaxy
Catalog (CGC) of 8547 galaxy candidates in the redshift range
z∼0.04-0.07, optical luminosity 1010-1011Lr☉, and X-ray
luminosity (0.5-7keV) LX=2x1040-2x1043erg/s. We estimate a ∼5%
false-match fraction and contamination by quasi-stellar objects
(QSOs). The CGC was extracted from the Chandra Source Catalog
version-2 (CSC2) by cross-correlating with optical and IR all-sky
survey data, including the Sloan Digital Sky Survey, Pan-STARRS, DESI
Legacy, and Wide-field Infrared Survey Explorer (WISE). Our selection
makes use of two main criteria that we have tested on the subsample
with optical spectroscopical identification. (1) A joint selection
based on X-ray luminosity (LX) and X-ray-to-optical flux ratio
(FXO), which recovers 63% of the spectroscopically classified
galaxies with a small contamination fraction (7%), which is a
significant improvement over methods using LX or FXO alone (<50%
recovery). (2) A joint W1-W2 (W12) WISE color and LX selection
that proves effective in excluding QSOs and improves our selection by
recovering 72% of the spectroscopically classified galaxies and
reducing the contamination fraction (4%). Of the CGC, 24% was selected
by means of optical spectroscopy; 30% on the basis of LX, FXO, and
W12; and 46% by using either the LX-FXO or the LX-W12
selection criteria. We have individually examined the data for
galaxies with z<0.1, which may include more than one CSC2 X-ray
source, leading to the exclusion of 110 local galaxies. Our catalog
also includes near-IR and UV data and galaxy morphological types.
Description:
The Chandra Source Catalog version 2 (CSC2; IX/57), released in 2019,
makes use of the first 15yr of Chandra observations (1999-2014),
coadded in overlapping regions of the sky to achieve the best
sensitivity. The CSC2 includes 317167 unique X-ray sources with
accurate positions and high-quality photometric, spectral, and
temporal properties.
We crossmatched 117358 high-quality X-ray sources selected from CSC2
with optical, IR, and UV catalogs to identify galaxies and obtain
multiwavelength data using the all-sky surveys SDSS DR16 (V/154),
PanSTARRS DR2, DESI Legacy DR8 (VII/292), AllWISE (II/328),
2MASS (II/246) and GALEX (II/335).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cgc.dat 588 8547 The Chandra X-ray Galaxy Catalog (CGC)
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Description of file:
Kim23_CGC.fits is the original file in FITS format.
See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
IX/45 : The Chandra Source Catalog, Release 1.1 (Evans+ 2012)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/328 : AllWISE Data Release (Cutri+ 2013)
II/349 : The Pan-STARRS release 1 (PS1) Survey - DR1 (Chambers+, 2016)
II/335 : Revised cat. of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
IX/62 : Catalog of CSC2.0-SDSS DR15 crossmatched sources (Rots+, 2021)
VII/292 : DESI Legacy Imaging Surveys DR8 (Duncan, 2022)
J/ApJ/644/829 : Chandra normal gal. at intermediate redshift (Kim+, 2006)
J/ApJS/169/401 : ChaMP X-ray point source catalog (Kim+, 2007)
J/ApJS/199/26 : The 2MASS Redshift Survey (2MRS) (Huchra+, 2012)
J/MNRAS/419/2095 : HMXBs in nearby galaxies (Mineo+, 2012)
J/ApJ/772/26 : AGN with WISE. II. The NDWFS Bootes field (Assef+, 2013)
J/ApJ/764/41 : X-ray binary evolution across cosmic time (Fragos+, 2013)
J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)
J/ApJ/825/7 : Evolution of ∼6Ms CDF-S galaxies (Lehmer+, 2016)
J/ApJ/817/34 : C-COSMOS Legacy multiwavelength cat. (Marchesi+, 2016)
J/AJ/153/114 : GCs in 27 nearby ETGs from the SLUGGS survey (Forbes+, 2017)
J/MNRAS/473/4937 : AllWISE ctp to ROSAT/2RXS & XMMSLEW2 cat. (Salvato+, 2018)
Byte-by-byte Description of file: cgc.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [2CXO_]
6- 21 A16 --- 2CXO 2CXO identifier (JHHMMSS.s+DDMMSS) (CSCID)
23- 41 A19 --- objID SDSS DR16 objID (SDSSID)
43- 60 A18 --- PS2ID Pan-STARRS DR2 objID (PSID)
62- 77 A16 --- LEGSID DESI DR8 Legacy South ls_id (LEGSID)
79- 97 A19 --- WISEA AllWISE designation (JHHMMSS.ss+DDMMSS.s)
(WISEID)
99- 114 A16 --- 2MASS 2MASS psc/xsc designation
(HHMMSSss+DDMMSSs; J2000) ( 2MASSID)
116- 134 A19 --- GALEX GALEX objID (GALEXID)
136- 145 F10.6 deg RAdeg Right ascension (J2000) (ra)
147- 156 F10.6 deg DEdeg [-65.6/86] Declination (J2000) (dec)
158- 165 F8.6 arcsec sepXS [0.003/3]? Separation between X-ray and
SDSS positions (sep_XS)
167- 174 F8.6 --- sepXP [0.002/3]? Separation between X-ray and
PS2 positions (sep_XP)
176- 183 F8.6 --- sepXL [0.002/3]? Separation between X-ray and
Legacy positions (sep_XL)
185- 192 F8.6 --- sepXW [0.0009/3]? Separation between X-ray and
WISE positions (sep_XW)
194 I1 --- spec [0/1]? 1 = galaxy is selected by the SDSS
spectroscopic class; see Section 5.1 (spec)
196 I1 --- phot [0/1]? 1 = galaxy with SDSS photo-z is
selected by LX-FXO; see Section 5.2 (photo)
198 I1 --- wph [0/1]? 1 = galaxy with SDSS photo-z is
selected by LX-W12; see Section 5.3 (wph)
200 I1 --- PS [0/1]? 1 = galaxy with Pan-STARRS photo-z
is selected by LX-FXO; see Section 5.3 (PS)
202 I1 --- wPS [0/1]? 1 = galaxy with Pan-STARRS photo-z
is selected by LX-W12;
see Section 5.3 (wPS)
204 I1 --- LS [0/1]? 1 = galaxy with Legacy South
photo-z is selected by LX-FXO;
see Section 5.3 (LS)
206 I1 --- wLS [0/1]? 1 = galaxy with Legacy South
photo-z is selected by LX-W12;
see Section 5.3 (wLS)
208- 216 E9.4 --- z [0.002/1.6] Redshift (z)
218- 226 E9.4 --- e_z [3.5e-06/0.4] z uncertainty (zErr)
228- 235 A8 --- r_z Reference on z (z_code) (1)
237- 244 F8.2 Mpc DL [10/11836] Luminosity distance, assuming
Ho=69.6 and ΩM=0.286 (d)
246- 250 F5.2 mag rmag [9.5/23.2] r-band magnitude (r)
252- 259 A8 --- r_rmag Reference on rmag (r_code) (2)
261- 268 F8.3 mag gmag [11.3/26.5]? g-band magnitude (g)
270- 277 A8 --- r_gmag Reference on gmag (g_code) (2)
279- 284 F6.3 mag Ksmag [10.9/17.3]? 2MASS Ks-band magnitude (k)
286- 293 F8.3 mag W1mag [10/18.1]? WISE W1 (3.4um) band magnitude
(W1)
295- 300 F6.1 --- w1SNR [2.3/52.2]? W1 S/N (w1snr)
302- 309 F8.3 mag W2mag [7.9/18]? WISE W2 (4.6um) band magnitude
(W2)
311- 316 F6.1 --- w2SNR [-3.7/58.1]? W2 S/N (w2snr)
318- 325 F8.3 mag W3mag [4.8/13.8]? WISE W3 (12um) band magnitude
(W3)
327- 332 F6.1 --- w3SNR [-5.4/78]? W3 S/N (w3snr)
334- 341 F8.3 mag W1-W2 [-1.5/2.4]? W1-W2 color index (W12)
343- 350 F8.3 mag W2-W3 [-0.1/5.6]? W2-W3 color index (W23)
352- 359 F8.5 mag NUVmag [15/23.7]? GALEX NUV magnitude (nuv_mag)
361- 368 F8.5 mag FUVmag [15.2/23.1]? GALEX FUV magnitude (fuv_mag)
370- 375 F6.2 --- S/N [1/219] Source flux significance from the
CSC2 master source table (significance)
377- 384 A8 --- LClass Highest detection likelihood
classification across all stacked
observations and energy bands
("MARGINAL"; or "TRUE", 6466 occurrences)
from CSC2 (IX/57) (likelihood_class)
386- 395 F10.4 10-15mW/m2 FxB15 [0.009/37561] X-ray flux in B band
(0.5-7keV); in units of
10-15erg/s/cm2 (FxB15)
397- 405 F9.4 10-15mW/m2 FxS15 [0.004/3928]? X-ray flux in S band
(0.5-2keV) in units of 10-15erg/s/cm2
(FxS15)
407- 415 F9.4 10-15mW/m2 FxH15 [0.01/3560]? X-ray flux in H band
(2-7keV) in units of 10-15erg/s/cm2
(FxH15)
417- 431 A15 --- f_FxB15 Source of the B-band flux from CSC2
(FxB_code) (3)
433- 448 A16 --- f_FxS15 Source of the S-band flux from CSC2
(FxS_code)
450- 464 A15 --- f_FxH15 Source of the H-band flux from CSC2
(FxH_code)
466- 476 F11.4 10+33W LxB40 [0.008/638682] X-ray luminosity in B band
(0.5-7keV) in units of 1040erg/s (LxB40)
478- 488 F11.4 10+33W LxS40 [0.004/161287]? X-ray luminosity in S
band (0.5-2keV) in units of 1040erg/s
(LxS40)
490- 500 F11.4 10+33W LxH40 [0.006/190175]? X-ray luminosity in H
band (2-7keV) in units of 1040erg/s
(LxH40)
502- 510 F9.5 Lsun Lr10 [0.0007/288] r-band luminosity, assuming
Mr☉=4.68mag (Lr10)
512- 519 F8.3 Lsun Lk10 [0.01/1215]? NIR luminosity in k band,
assuming Mk☉=3.28mag (Lk10)
521- 525 F5.2 --- logFxo [-5.8/1.8] X-ray-to-optical flux ratio,
log(Fx/Fo); see Section 5.1.1 (logFxo)
527- 532 A6 --- ClSDSS SDSS spectroscopic class
("GALAXY": 2023 occurrences;
"STAR": 1 occurrence) (class_SDSS) (4)
534- 544 A11 --- sClSDSS SDSS spectroscopic subclass (subclass_SDSS)
546- 551 A6 --- ClPS Pan-STARRS class
(GALAXY, QSO, STAR or UNSURE) (class_PS)
553- 555 A3 --- TypePS Pan-STARRS type
("E" for early-type galaxies,
"S" for spiral galaxies) (ype_PS)
557- 560 A4 --- TypeLEG Legacy type ("DEV" = de Vaucouleurs;
"REX" = round exponential galaxy;
"EXP" = exponential or
"COMP" = composite) (type_EG)
562- 567 F6.4 --- CSp [0/1]? Fraction of Galaxy Zoo votes for
combined spiral
(clockwise + counterclockwise + edge-on)
(pcsSDSS) (5)
569- 574 F6.4 --- Ell [0/1]? Fraction of Galaxy Zoo votes for
elliptical (pelSDSS) (5)
576- 581 F6.4 --- Merger [0/1]? Fraction of Galaxy Zoo votes for
merger (pmgSDSS) (5)
583- 588 F6.4 --- Unk [0/1]? Fraction of Galaxy Zoo votes for
do not know (pdkSDSS) (5)
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Note (1): Source code as follows:
z_PSph = Pan-STARRS DR2 photo-z (3261 occurrences)
z_SDSSsp = SDSS DR16 spec-z (2018 occurrences)
z_SDSSph = SDSS DR16 photo-z (1849 occurrences)
z_LEGSph = DESI Legacy DR8 photo-z (1290 occurrences)
z_LEGSsp = DESI Legacy DR8 spec-z (43 occurrences)
2MRS = 2MASS redshift survey (Huchra+ 2012, J/ApJS/199/26 ; 86 occurrences)
Note (2): Source code as follows:
r_SDSS = rmag from SDSS DR16 (3952 occurrences)
r_LEGS = rmag from Legacy South (1327 occurrences)
r_PSkron = rmag from Pan-STARRS kron mag (3217 occurrences)
r_PSap = rmag from Pan-STARRS aperture mag (51 occurrences)
g_SDSS = gmag from SDSS DR16 (3952 occurrences)
g_LEGS = gmag from Legacy South (1491 occurrences)
g_PSkron = gmag from Pan-STARRS kron mag (2764 occurrences)
g_PSap = gmag from Pan-STARRS aperture mag (73 occurrences)
Note (3): Source code as follows:
fluxaperb = aperture flux in B band (95%)
fluxapera = sum of the S and H fluxes if fluxaperb is unavailable (5%)
fluxaperw = aperture flux in W band for HRC only (0.1%)
Note (4): One galaxy (2CXO J143456.7+340627), classified as a G2 star in the
SDSS spectroscopic class, was first rejected in the spec-z sample but
was reselected by both LX-FXO and LX-W12 methods. We checked
the optical images and confirmed that it is a spiral galaxy.
Note (5): We extracted morphological types from the Galaxy Zoo 1 release in the
SDSS Zoo-Votes table (Lintott+ 2008MNRAS.389.1179L 2008MNRAS.389.1179L). See Appendix B.
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 22-Nov-2023