J/ApJ/890/150 X-ray binaries in M101 with HST optical data (Chandar+, 2020)
A new window into the nature of X-ray binaries in M101 from their optical
emission.
Chandar R., Johns P., Mok A., Prestwich A., Gallo E., Hunt Q.
<Astrophys. J., 890, 150-150 (2020)>
=2020ApJ...890..150C 2020ApJ...890..150C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, optical; Binaries, X-ray; Photometry, HST; X-ray sources
Keywords: Spiral galaxies; High mass x-ray binary stars
Low-mass x-ray binary stars; X-ray binary stars
Abstract:
The high-energy emission from nearby, star-forming galaxies is
dominated by X-ray binaries, where a neutron star or black hole is
accreting mass from either a low-mass (≲M☉) or high-mass
(≳8M☉) star. Donor stars with intermediate masses ∼3-7M☉
are also possible, but rarer in our Galaxy. Since it is not possible
to separate low-, intermediate-, and high-mass X-ray binaries (LMXBs,
IMXBs, and HMXBs) from their X-ray properties alone, we use optical
images of M101 taken with the Hubble Space Telescope to directly
constrain the masses of donor stars in X-ray binaries down to
∼3M☉. For X-ray binaries that still live within their parent
star cluster, the age of the cluster provides strong constraints on
the mass of the donor and hence type of binary. We present the
classification, on a source-by-source basis, of 140 X-ray point
sources in the nearby spiral galaxy M101 (D=6.4±0.2Mpc). We find
that, overall, HMXBs appear to follow the spiral arms, while LMXBs
dominate the bulge region as expected, but also appear to form an
inter-arm disk population. The X-ray luminosity functions for HMXBs
and LMXBs are well fit by a power-law distribution,
dN/dLX∝Lα, with α=-1.71±0.06 (HMXBs) and
α=-1.96±0.08 (LMXBs), and the brightest sources are consistent
with the expectations from sampling statistics without requiring a
physical cutoff. Overall, our results for HMXB and LMXB populations
agree well with the specific star formation rate map presented for
M101 recently by Lehmer and collaborators.
Description:
M101 has been extensively observed by the ACIS instrument on Chandra,
with 27 individual exposures totalling close to 1Ms. We selected an
initial X-ray list by searching for sources observed with the ACIS
detector within 6' of the center of M101 in the CSC 2.0 (IX/57).
M101 has been observed with the HST through several different
programs. Here, we use the 10 pointings observed in the B, V, and I
bands with the Wide Field Channel (WFC) of the Advanced Camera for
Surveys (ACS) taken as part of program GO-9490 (PI: K. Kuntz). Each
pointing was observed with two exposures for a total of 15 minutes in
the B band, and 12 minutes in each of the V and I bands.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 127 145 M101 X-ray point source properties
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
B/hst : HST Archived Exposures Catalog (STScI, 2007)
IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)
J/ApJ/613/279 : ACS Virgo Cluster Survey. III. M87 (Jordan+, 2004)
J/ApJ/662/525 : LMXBs in globular clusters of 5 galaxies (Kundu+, 2007)
J/ApJ/689/983 : LMXBs in early-type galaxies. I. Chandra (Humphrey+, 2008)
J/MNRAS/392/L55 : Globular clusters in M31 from K-band phot. (Peacock+, 2009)
J/ApJ/693/8 : High-redshift QSOs in the COSMOS survey (Brusa+, 2009)
J/ApJ/733/124 : Cepheids in M101 observed with HST (Shappee+, 2011)
J/ApJ/741/86 : XRBs and star clusters in NGC 4449 (Rangelov+, 2011)
J/MNRAS/419/2095 : HMXBs in nearby galaxies (Mineo+, 2012)
J/ApJ/805/160 : Old star clusters in M101 from HST (Simanton+, 2015)
J/ApJS/228/2 : Chandra Deep Field-South survey: 7Ms sources (Luo+, 2017)
J/ApJS/239/13 : Chandra PHAT X-ray catalog of the M31 disk (Williams+, 2018)
J/ApJS/243/3 : Chandra observations of SINGS galaxies (Lehmer+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1/162] Internal identifier
5- 16 F12.8 deg RAdeg [210.63/210.97] Right Ascension (J2000)
18- 28 F11.8 deg DEdeg [54.25/54.44] Declination (J2000)
30- 35 F6.2 [10+29W] logLx [0.1/206] log 0.3-8keV X-ray luminosity
37- 42 F6.2 [10+29W] e_logLx [0.3/541] Uncertainty in logLx
44- 48 F5.2 mag Vmag [20.29/29.15]? Apparent HST V band magnitude
50- 53 F4.2 mag e_Vmag [0.01/0.5]? Uncertainty in Vmag
55- 59 F5.2 mag B-V [-0.7/3.1]? The (B-V) color index
61- 64 F4.2 mag e_B-V [0.03/1.3]? Uncertainty in B-V
66- 70 F5.2 mag V-I [-2.4/5.8]? The (V-I) color index
72- 75 F4.2 mag e_V-I [0.02/0.6]? Uncertainty in V-I
77- 92 A16 --- Class Classification (1)
94 I1 --- Q [1/3] Quality flag (1=high confidence) (2)
96-127 A32 --- Notes Additional notes
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Note (1): Class as follows:
HMXB = High-mass X-ray binary (49 occurrences)
LMXB = Low-mass X-ray binary (47 occurrences)
IMXB = Intermediate-mass X-ray binary (33 occurrences)
AGN = 9 occurrences
Foreground Star = 6 occurrences
Quasar Candidate = 1 occurrence
Note (2): Confidence flag as follows:
1 = high confidence; X-ray sources with one candidate donor within 2σ
in a region of low extinction.
2 = medium confidence
3 = low confidence
See Section 3.1 for full details.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-Aug-2021