J/MNRAS/491/3606 Effects of metallicity on HMXB formation (Ponnada+, 2020)
Effects of metallicity on high-mass X-ray binary formation.
Ponnada S., Brorby M., Kaaret P.
<Mon. Not. R. Astron. Soc., 491, 3606-3612 (2020)>
=2020MNRAS.491.3606P 2020MNRAS.491.3606P (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, X-ray ; Galaxies ; X-ray sources ; Abundances ;
Photometry, ultraviolet ; Infrared
Keywords: galaxies: dwarf - galaxies: starburst - X-rays: galaxies
Abstract:
The heating of the intergalactic medium in the early, metal-poor
Universe may have been partly due to radiation from high-mass X-ray
binaries (HMXBs). Previous investigations on the effect of metallicity
have used galaxies of different types. To isolate the effects of
metallicity on the production of HMXBs, we study a sample consisting
only of 46 blue compact dwarf galaxies covering metallicity in the
range 12+log(O/H) of 7.15-8.66. To test the hypothesis of metallicity
dependence in the X-ray luminosity function (XLF), we fix the XLF form
to that found for near-solar metallicity galaxies and use a Bayesian
method to constrain the XLF normalization as a function of star
formation rate for three different metallicity ranges in our sample.
We find an increase by a factor of 4.45±2.04 in the XLF
normalization between the metallicity ranges 7.1-7.7 and 8.2-8.66 at a
statistical significance of 99.79 per cent. Our results suggest that
HMXB production is enhanced at low metallicity, and consequently that
HMXBs may have contributed significantly to the reheating of the early
Universe.
Description:
We expand a set of 25 blue compact dwarfs (BCDs) studied in Brorby et
al. (2014MNRAS.441.2346B 2014MNRAS.441.2346B), by selecting BCDs over all metallicities up
to a distance of 60Mpc. Cross-referencing the BCD population defined
by Izotov, Thuan & Stasinska (2007ApJ...662...15I 2007ApJ...662...15I, Cat. J/ApJ/662/15)
and the NED catalogue with the Chandra archive, we find a total of 21
additional BCDs with Chandra observations, GALEX observations, and
published metallicities. We add this to our sample for an overall
sample size of 46 BCDs.
For the final sample, we determine SFRs using GALEX (UV) data
following the methods used in previous studies, Brorby et al.
(2014MNRAS.441.2346B 2014MNRAS.441.2346B) and Brorby et al. (2016MNRAS.457.4081B 2016MNRAS.457.4081B). We
obtain metallicities from published values, all of them obtained
through the direct-temperature method, with an exception. The distance
and metallicity measurements from reported values in the literature
are listed in Table A1. X-ray source photometry information is listed
in Table A2 and our UV and IR measurements and corresponding SFRs are
detailed in Table A3.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 69 46 BCDs including the Brorby et al.
(2014MNRAS.441.2346B 2014MNRAS.441.2346B) and NED sample
tablea2.dat 65 46 X-ray source photometry
tablea3.dat 79 46 UV measurements and SFRs
--------------------------------------------------------------------------------
See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
J/ApJ/662/15 : Abundances in extragalactic HII regions (Izotov+, 2007)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Galaxy name
21- 25 I5 --- ID ObsID from Chandra
27- 30 F4.2 [-] 12+log(O/H) Oxygen abundance 12+log(O/H)
32 A1 --- r_12+log(O/H) Reference for 12+log(O/H) (1)
34- 35 I2 h RAh Right ascension (J2000)
37- 38 I2 min RAm Right ascension (J2000)
40- 44 F5.2 s RAs Right ascension (J2000)
46 A1 --- DE- Declination sign (J2000)
47- 48 I2 deg DEd Declination (J2000)
50- 51 I2 arcmin DEm Declination (J2000)
53- 57 F5.2 arcsec DEs Declination (J2000)
59- 63 F5.2 ks Exptime Chandra exposure time
65- 69 F5.2 Mpc Dist Distance
--------------------------------------------------------------------------------
Note (1): References as follows:
a = Brorby et al. (2014MNRAS.441.2346B 2014MNRAS.441.2346B)
b = Thuan et al. (2016MNRAS.463.4268T 2016MNRAS.463.4268T)
c = Izotov, Thuan & Guseva (2014MNRAS.445..778I 2014MNRAS.445..778I)
d = Engelbracht et al. (2008ApJ...678..804E 2008ApJ...678..804E)
e = Zhao et al. (2013ApJ...764...44Z 2013ApJ...764...44Z)
f = Izotov & Thuan (2004ApJ...602..200I 2004ApJ...602..200I, Cat. J/ApJ/602/200)
g = Zhao, Gao & Gu (2010ApJ...710..663Z 2010ApJ...710..663Z)
h = Guseva, Izotov & Thuan (2000ApJ...531..776G 2000ApJ...531..776G)
i = Kreckel et al. (2015ApJ...798L..15K 2015ApJ...798L..15K)
j = Pilyugin & Thuan (2007ApJ...669..299P 2007ApJ...669..299P)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Galaxy name
21 A1 --- f_Name [*] Flag on Name (1)
23- 27 F5.2 10+20cm-2 nH Column density obtained using the Colden
tool
29- 34 F6.2 arcsec R25 R25 taken from HyperLeda and modified as
described in Section 3
36- 41 F6.2 arcsec R25HL Major axis radius at the 25B-mag/arcsec2
from HyperLeda (R25=D25/2)
43- 48 F6.1 deg PA [] Position angle from HyperLEDA
50- 51 I2 --- NsupLmin Number of observed sources within the
D25 ellipse with luminosity greater
than Lmin
53- 58 F6.4 --- Nbkg Number of expected background sources
within the D25 ellipse, as determined
by logN-logS curves of
Georgakakis et al. (2008MNRAS.388.1205G 2008MNRAS.388.1205G)
60- 65 F6.3 10+31W Lmin Luminosity limit calculated for the
0.5-8.0keV energy band
--------------------------------------------------------------------------------
Note (1): Flag as follows:
* = Denotes galaxies without source detections constraining the Mineo
relation
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Galaxy name
21- 26 F6.4 mag E(B-V) Extinction obtained using the Infrared
Science Archive (IRSA) tool DUST
28- 34 F7.3 ct/s CRFUV Count rate in the FUV band of GALEX
observations
36- 42 F7.3 10+19W/Hz LFUV Luminosity in the FUV band, 1350-1750Å
44- 51 F8.3 10-3Msun/yr SFRFUV Star formation rate as determined by the
Hunter et al. (2010AJ....139..447H 2010AJ....139..447H) method
53- 60 F8.3 ct/s CRNUV Count Rate in the NUV band of GALEX,
1750-2800Å
62- 69 F8.3 10-3Msun/yr SFRNUV Star formation rate in the NUV
71- 79 F9.4 10-3Msun/yr SFRIR ? Star formation rate in the IR via Spitzer
images (Brorby et al. 2014MNRAS.441.2346B 2014MNRAS.441.2346B)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 20-Feb-2023