J/ApJS/243/3 Chandra observations of SINGS galaxies (Lehmer+, 2019)
X-ray binary luminosity function scaling relations for local galaxies based on
subgalactic modeling.
Lehmer B.D., Eufrasio R.T., Tzanavaris P., Basu-Zych A., Fragos T.,
Prestwich A., Yukita M., Zezas A., Hornschemeier A.E., Ptak A.
<Astrophys. J. Suppl. Ser., 243, 3-3 (2019)>
=2019ApJS..243....3L 2019ApJS..243....3L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby; Binaries, X-ray; X-ray sources
Keywords: galaxies: evolution; stars: formation; X-rays: binaries;
X-rays: galaxies
Abstract:
We present new Chandra constraints on the X-ray luminosity functions
(XLFs) of X-ray binary (XRB) populations, as well as their scaling
relations, for a sample of 38 nearby galaxies (D=3.4-29Mpc). Our
galaxy sample is drawn primarily from the Spitzer Infrared Nearby
Galaxies Survey (SINGS) and contains a wealth of Chandra (5.8Ms total)
and multiwavelength data, allowing for star formation rates (SFRs) and
stellar masses (M*) to be measured on subgalactic scales. We divided
the 2478 X-ray-detected sources into 21 subsamples in bins of specific
SFR (sSFR=SFR/M*) and constructed XLFs. To model the XLF dependence
on sSFR, we fit a global XLF model, containing contributions from
high-mass XRBs (HMXBs), low-mass XRBs (LMXBs), and background sources
from the cosmic X-ray background that respectively scale with SFR,
M*, and sky area. We find an HMXB XLF that is more complex in shape
than previously reported and an LMXB XLF that likely varies with sSFR,
potentially due to an age dependence. When applying our global model
to XLF data for each individual galaxy, we discover a few galaxy XLFs
that significantly deviate from our model beyond statistical scatter.
Most notably, relatively low-metallicity galaxies have an excess of
HMXBs above ∼1038erg/s, and elliptical galaxies that have relatively
rich populations of globular clusters (GCs) show excesses of LMXBs
compared to the global model. Additional modeling of how the XRB XLF
depends on stellar age, metallicity, and GC specific frequency is
required to sufficiently characterize the XLFs of galaxies.
Description:
In this paper, we have utilized 5.8Ms of Chandra ACIS data, combined
with UV-to-IR observations, for 38 nearby (D≲30Mpc) Spitzer Infrared
Nearby Galaxies Survey (SINGS; Kennicutt+ 2003PASP..115..928K 2003PASP..115..928K)
galaxies to revisit scaling relations of the HMXB and LMXB X-ray
luminosity functions (XLFs) with SFR and M*, respectively.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
sings.dat 7 41 List of SINGS galaxies; table added by CDS
table2.dat 92 200 Chandra Advanced CCD Imaging Spectrometer (ACIS)
observation log
table7.dat 91 4442 X-ray point-source catalog and properties
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
J/ApJ/586/794 : Multiwavelength luminosities of galaxies (Bell, 2003)
J/ApJ/602/231 : Chandra X-ray point sources in nearby gal. (Colbert+, 2004)
J/ApJ/617/240 : Oxygen abundances in the GOODS-North field (Kobulnicky+, 2004)
J/ApJ/681/197 : ACS Virgo Cluster Survey. XV (Peng+, 2008)
J/ApJ/695/580 : Oxygen abundance in M83 (Bresolin+, 2009)
J/ApJS/190/233 : Spectroscopy and abundances of SINGS gal. (Moustakas+, 2010)
J/MNRAS/419/2095 : HMXBs in nearby galaxies (Mineo+, 2012)
J/ApJ/764/41 : X-ray binary evolution across cosmic time (Fragos+, 2013)
J/ApJ/772/82 : A catalog of globular cluster systems (Harris+, 2013)
J/ApJ/774/136 : SINGS gal. X-ray data compared to models (Tzanavaris+, 2013)
J/AJ/146/86 : Cosmicflows-2 catalog (CF2) (Tully+, 2013)
J/ApJ/776/L31 : Energy feedback from XRB from z=0 to z=19.92 (Fragos+, 2013)
J/MNRAS/440/2265 : Spectroscopy of NGC3310 HII reg. (Miralles-Caballero+, 2014)
J/ApJS/212/21 : A deep Chandra ACIS survey of M83 (Long+, 2014)
J/ApJ/817/95 : X-ray observations of HCG galaxies (Tzanavaris+, 2016)
J/ApJ/825/7 : Evolution of ∼6Ms CDF-S galaxies (Lehmer+, 2016)
J/MNRAS/466/1019 : Bright HMXBs in THINGS galaxies (Sazonov+, 2017)
J/ApJ/865/43 : X-ray analysis of Chandra-COSMOS gal. (Fornasini+, 2018)
Byte-by-byte Description of file: sings.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [NGC]
4- 7 I4 --- NGC NGC number of the host galaxy
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- Gal Name of the host galaxy
9- 11 A3 --- --- [NGC]
12- 15 I4 --- NGC NGC number of the host galaxy as in Table 7;
column added by CDS
17- 21 I5 --- ObsID [354/21676]? Chandra Observation ID;
null for merged IDs
23 A1 --- f_ObsID [de] Flag on ObsID (1)
25- 35 F11.7 deg RAdeg Right Ascension, Aim Point (J2000)
37- 47 F11.7 deg DEdeg Declination, Aim Point (J2000)
49- 67 A19 "datime" ObsDate UT Observation Date time
69- 71 I3 ks Exp [2/892] Total exposure time (2)
73 I1 --- Nfl [1/2]? Number of flaring intervals, rejected
76- 78 F3.1 ks Tfl [0.5/2]? Combined flare duration, rejected
80- 84 F5.2 arcsec dRA [-0.7/0.8]? Offset in Right Ascension
86- 90 F5.2 arcsec dDE [-1.3/0.6]? Offset in Declination
92- 92 A1 --- Mode [FV] Observation Mode (F=faint mode;
or V=very faint mode)
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Note (1): Flag on Observations, including merged datasets as follows:
d = Indicates Obs. ID by which all other observations are reprojected to
for alignment purposes. This Obs. ID was chosen for reprojection as
it had the longest initial exposure time, before flaring intervals
were removed;
e = Merged observations (ObsID is null) where the RAdeg,DEdeg of the aim
point represents exposure-time weighted value.
Note (2): All observations were continuous. These times have been corrected
for removed data that were affected by high background; see Section 3.2.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [NGC]
4- 7 I4 --- NGC NGC number of the host galaxy
9- 11 I3 --- ID Point-source identification number
within the galaxy
13- 22 F10.6 deg RAdeg Right Ascension, point source (J2000)
24- 33 F10.6 deg DEdeg Declination, point source (J2000)
35- 38 F4.1 arcmin theta [0/12.4] Offset (1)
40- 47 F8.1 ct NFB [0.7/114995] Net (background subtracted)
0.5-7keV counts
49- 53 F5.1 ct e_NFB [1/359] 1σ uncertainty in NFB
55- 60 F6.3 10+22cm-2 NH [0.008/15.5] Best-fit column density (2)
62- 67 F6.3 10+22cm-2 e_NH [0.001/14]?=-1 1σ uncertainty in NH (2)
69- 72 F4.2 --- Gamma [0.09/3.3] Best-fit photon index, Γ (2)
74- 78 F5.2 --- e_Gamma [0.01/3]?=-1 1σ uncertainty in Gamma (2)
80- 84 F5.1 [mW/m2] logFFB [-16.6/-11.4] log, 0.5-8keV source flux
86- 89 F4.1 [10-7W] logLFB [34.8/41] log, 0.5-8keV source luminosity
91- 91 I1 --- Loc [1/5] Location Flag (3)
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Note (1): Offset of the point source with respect to the average aim point
of the Chandra observations.
Note (2): Best-fit column density NH and photon index Γ, respectively,
along with their respective 1σ errors, based on spectral fits to an
absorbed power-law model (TBABS * POW in xspec). For sources with small
numbers of counts (<20 net counts), we adopted Galactic absorption
appropriate for each galaxy and a photon index of Γ=1.7.
Note (3): Flag indicating the location of the source within the galaxy.
Flag as follows:
1 = the source is within the Ks-band footprint adopted in Table 1, and
outside a central region of avoidance, if applicable. All XLF
calculations are based on Flag=1 sources;
2 = source is within the Ks-band footprint, but has a luminosity of
L<10+35erg/s, and was thus excluded from our XLF analysis;
3 = indicates that the source is outside the 20mag/arcsec2 Ks-band
ellipse of the galaxy, but within the "total" Ks-band ellipse.
4 = the source is located in the central region of avoidance due to
either the presence of an AGN or very high levels of source
confusion.
5 = indicates that the source is outside the "total" Ks-band ellipse.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Dec-2019