J/ApJ/932/27 The redshift evolution of ULXs out to z∼0.5 (Barrows+, 2022)
The redshift evolution of ultraluminous X-ray sources out to z∼0.5: comparison
with X-ray binary populations and contribution to the cosmic X-ray background.
Barrows R.S., Comerford J.M., Stern D., Heida M.
<Astrophys. J., 932, 27 (2022)>
=2022ApJ...932...27B 2022ApJ...932...27B
ADC_Keywords: Binaries, X-ray; Galaxies, optical; X-ray sources; Redshifts
Keywords: X-ray binary stars ; Star formation ; Neutron stars ; Stellar
mass black holes ; Metallicity ; Ultraluminous x-ray sources ;
X-ray sources
Abstract:
Ultraluminous X-ray sources (ULXs) are thought to be powerful X-ray
binaries (XRBs) and may contribute significantly to the
redshift-dependent X-ray emission from star-forming galaxies. We have
assembled a uniform sample of 259 ULXs over the redshift range
z=0.002-0.51 to constrain their physical nature and their contribution
to the cosmic X-ray background. The sample is constructed by
crossmatching galaxies from the Sloan Digital Sky Survey with the
Chandra Source Catalog and selecting off-nuclear X-ray sources after
applying astrometric corrections. The fraction of contaminants is ∼30%
and shows no evolution with redshift. The host-galaxy star formation
rates (SFRs) are systematically elevated relative to the parent sample
when matched in host stellar mass. The specific SFRs suggest a slight
preference for high-mass XRBs, and the X-ray luminosity scaling
relations with host-galaxy stellar mass and SFR indicate that the
highest-redshift sources represent relatively luminous XRB populations
that dominate their host-galaxy X-ray emission. The fraction of
galaxies hosting at least one ULX of a given luminosity increases with
redshift over the full range of our sample, as expected if ULXs are
preferentially found in galaxies with high SFRs and low metallicities.
At z∼0.5, the ULX X-ray flux is consistent with the X-ray emission
from star-forming galaxies. Moreover, ULXs may account for up to ∼40%
of the integrated flux from XRBs in the normal galaxy population out
to z∼0.5, suggesting they may contribute significantly to the overall
ionizing radiation from galaxies.
Description:
The initial galaxy sample is derived from the catalog of Sloan Digital
Sky Survey (SDSS) detections in Data Release 16 (DR16, V/154) that are
classified as Galaxy and with measured photometric redshifts (zphot).
The High Resolution Camera (HRC) and the Advanced CCD Imaging
Spectrometer (ACIS) on the Chandra X-Ray Observatory provide the best
spatial resolution of current X-ray telescopes and are therefore
optimal for identifying off-nuclear X-ray sources out to intermediate
redshifts. To obtain the most comprehensive list of robust source
detections from Chandra, we use the Chandra Source Catalog Version 2
(CSC2, IX/57) Master Sources as our initial sample of X-ray sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 103 259 Ultraluminous X-ray source (ULX) candidates
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See also:
IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
II/335 : Revised cat. of GALEX UV sources (GUVcat_AIS GR6+7) (Bianchi+ 2017)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
J/ApJS/143/25 : Intermediate-luminosity X-ray objects cat. (Colbert+, 2002)
J/ApJ/602/231 : Chandra X-ray point sources in nearby gal. (Colbert+, 2004)
J/ApJS/154/519 : Properties of ultraluminous X-ray candidates (Swartz+, 2004)
J/ApJS/157/59 : Ultraluminous X-ray sources in nearby galaxies (Liu+, 2005)
J/A+A/429/1125 : Catalog of Ultraluminous X-ray sources (Liu+, 2005)
J/ApJ/649/730 : ULX population in nearby galaxies from XMM (Winter+, 2006)
J/ApJS/166/211 : Chandra sources in Antennae galaxies (Zezas+, 2006)
J/ApJS/192/10 : Chandra ACIS survey in 383 nearby galaxies. I. (Liu, 2011)
J/ApJ/741/49 : ULX candidates in nearby galaxies (Swartz+, 2011)
J/MNRAS/416/1844 : 2XMM ultraluminous X-ray source candidates (Walton+, 2011)
J/MNRAS/419/2095 : HMXBs in nearby galaxies (Mineo+, 2012)
J/ApJ/776/L31 : Energy feedback from XRB from z=0 to z=19.92 (Fragos+, 2013)
J/ApJ/764/41 : X-ray binary evolution across cosmic time (Fragos+, 2013)
J/A+A/582/A121 : Dust properties in galaxies (Remy-Ruyer+, 2015)
J/ApJS/222/12 : Luminous X-ray cand. within D25 of galaxies (Gong+, 2016)
J/ApJ/825/7 : Evolution of ∼6Ms CDF-S galaxies (Lehmer+, 2016)
J/ApJS/234/23 : The WISE AGN candidates catalogs (Assef+, 2018)
J/ApJ/882/181 : Luminous X-ray sources from SDSS & CSC2 (Barrows+, 2019)
J/MNRAS/483/5554 : Non-nuclear X-ray sources in nearby gal. (Earnshaw+, 2019)
J/MNRAS/498/4790 : Ultralum. X-ray sources in local Universe (Kovlakas+, 2020)
J/ApJS/251/2 : CDWFS: Chandra survey in Bootes. I. (Masini+, 2020)
J/MNRAS/491/3606 : Effects of metallicity on HMXB formation (Ponnada+, 2020)
J/ApJ/922/179 : Host galaxies phot. for WISE-selected AGNs (Barrows+, 2021)
J/PASJ/73/1315 : Extragalactic X-ray binaries catalog (Inoue+, 2021)
J/ApJ/907/17 : HMXB-dominant galaxy sample and properties (Lehmer+, 2021)
J/MNRAS/509/1587 : 4XMM-DR10/CSC2/2SXPS ULX candidates (Walton+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- --- [2CXO]
6- 21 A16 --- 2CXO ULX candidate CSC2 identifier
(JHHMMSS.s+DDMMSS)
23- 42 A20 --- Gal ULX candidate host galaxy identifier
(JHHMMSS.ss+DDMMSS.ss)
44- 50 F7.5 --- z [0.0016/0.51] Best available host galaxy
redshift (1)
52 A1 --- f_z [ab] Flag on z (2)
54- 58 F5.2 kpc Offset [0.07/35] Candidate offset from host
galaxy centroid
60- 63 F4.2 kpc e_Offset [0.02/6] Uncertainty in Offset
65- 69 F5.1 10+32W Lum [0.7/423.3] Unabsorbed, rest-frame 0.5-7keV
luminosity; 1039erg/s
71- 75 F5.1 10+32W e_Lum [0.1/330] Lower uncertainty in Lum
77- 81 F5.1 10+32W E_Lum [0.1/314] Upper uncertainty in Lum
83- 86 F4.1 [Msun] logMs [5.5/13.8] Log host galaxy stellar mass
88- 91 F4.2 [Msun] e_logMs [0.01/2] Uncertainty in logMs
93- 97 F5.1 [Msun/yr] SFR [-10.4/2.3] Log star formation rate
99- 103 F5.2 [Msun/yr] e_SFR [0.01/11] Uncertainty in SFR
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Note (1): If a galaxy is in the SDSS spectroscopic sample, then we adopt the
spectroscopic redshift (zspec) as the final redshift value (z).
Otherwise, we query the NASA Extragalactic Database (NED) for a
spectroscopic redshift using a crossmatch radius of 5'. If multiple
source matches are found, we take the closest match. Furthermore, if a
matched source has multiple values of zspec, then the value with the
smallest uncertainty is used.
If no value of zspec is available, then that of zphot is used.
See Section 2.1.
Note (2): Flag as follows:
a = photometric redshift (59 occurrences)
b = spectroscopic redshift (200 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Esther Collas [CDS] 08-Apr-2024