J/ApJ/689/983 LMXBs in early-type galaxies. I. Chandra (Humphrey+, 2008)
Low-mass X-ray binaries and globular clusters in early-type galaxies.
I. Chandra observations.
Humphrey P.J., Buote D.A.
<Astrophys. J., 689, 983-1004 (2008)>
=2008ApJ...689..983H 2008ApJ...689..983H
ADC_Keywords: Abundances, [Fe/H] ; Galaxies, optical ; Binaries, X-ray
Keywords: galaxies: elliptical and lenticular, cD - galaxies: star clusters -
X-rays: binaries - X-rays: galaxies
Abstract:
We present a Chandra survey of LMXBs in 24 early-type galaxies.
Correcting for detection incompleteness, the X-ray luminosity function
(XLF) of each galaxy is consistent with a power law with negative
logarithmic differential slope, β∼2.0. However, β strongly
correlates with incompleteness, indicating the XLF flattens at
low-LX. Although the XLFs are similar, we find evidence of some
variation between galaxies. The high-LX XLF slope does not correlate
with age, but may correlate with [α/Fe]. Considering only LMXBs
with LX>1037ergs/s, matching the LMXBs with globular clusters
(GCs) identified in HST observations of 19 of the galaxies, we find
the probability a GC hosts an LMXB is proportional to
LαGCZγFe where α=1.01±0.19 and
γ=0.33±0.11. The spatial distribution of LMXBs resembles that
of GCs, and the specific frequency of LMXBs is proportional to the GC
specific luminosity, consistent with the hypothesis that all LMXBs
form in GCs.
Description:
Chandra ACIS observations of the 24 galaxies were made between 2000
January and 2003 April. A summary of their properties, and the Chandra
observations used, are listed in Table 1. HST observations and
analysis are described in Paper II (Humphrey, Cat. J/ApJ/690/512).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 97 24 Target list and observation details
table6.dat 95 1194 LMXB Source lists
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-)
VII/176 : Photometry and Spectroscopy of Elliptical Galaxies (Faber+ 1989)
VII/155 : Third Reference Cat. of Bright Galaxies (RC3) (de Vaucouleurs+ 1991)
J/ApJ/599/218 : Chandra LMXB in NGC 4365 and NGC 4382 (Sivakoff+, 2003)
J/ApJ/586/814 : NGC 4472 Chandra/HST study (Maccarone+, 2003)
J/ApJ/600/729 : Chandra LMXB in NGC 4649 (Randall+, 2004)
J/ApJ/612/848 : Chandra LMXB in NGC 1332 (Humphrey+, 2004)
J/ApJ/690/512 : LMXBs and GCs in early-type galaxies. II. (Humphrey 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Target galaxy name (NGC or IC number)
10- 24 A15 --- Type Morphological type
26- 29 F4.1 Mpc Dist Distance (1)
31- 33 F3.1 arcmin D25 B-band 25th magnitude isophote (D25)
diameters taken from RC3 (Cat. VII/155)
35- 38 F4.2 10+11Lsun LK 2MASS K-band luminosity (2)
40- 43 F4.1 Gyr Age ? Age (3)
45- 47 F3.1 Gyr E_Age ? Positive Age 1σ error
49- 51 F3.1 Gyr e_Age ? Negative Age 1σ error
53- 57 F5.2 [Sun] [Fe/H] ? Metallicity of [Fe/H] (3)
59- 63 F5.3 [Sun] e_[Fe/H] ? 1σ error of [Fe/H]
65- 68 F4.2 [Sun] [a/Fe] ? Metallicity of [α/Fe] (3)
70- 74 F5.3 [Sun] e_[a/Fe] ? 1σ error of [a/Fe]
76- 79 I4 --- OID Chandra observation identifier
81 A1 --- S/I [SI] ACIS instrument mode (Spectrum/Image)
83- 92 A10 "YYYY/MM/DD" Date Observation date start
94- 97 F4.1 ks Exp Total exposure time; flaring removed (see
section 2 for further details)
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Note (1): Distances from Tonry et al. (2001ApJ...546..681T 2001ApJ...546..681T) corrected for
the new Cepheid zero point (Jensen et al. 2003ApJ...583..712J 2003ApJ...583..712J), except
for IC 4296, taken from Jensen et al. (2003ApJ...583..712J 2003ApJ...583..712J) and NGC
5018 from Dn-σ relation (Faber et al. 1989, Cat. VII/176).
Note (2): K-band luminosities (LK) were taken from 2MASS (Jarrett T.H.,
2000PASP..112.1008J 2000PASP..112.1008J), adopting M{K☉_}=3.41.
Note (3): The ages and metallicities were computed as described in Humphrey
& Buote (2006ApJ...639..136H 2006ApJ...639..136H) and Humphrey et al.
(2006ApJ...646..899H 2006ApJ...646..899H). See section 6.1.3 for further details.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Name Host galaxy identification (NGC or IC number)
10- 13 A4 --- --- [CXOU]
15- 30 A16 --- CXOU Source identification (JHHMMSS.s+DDMMSS)
32- 36 F5.1 ct Cts Total counts detected
38- 44 F7.3 10+31W LX X-ray (0.3-7keV) luminosity; units of 1038erg/s
46- 51 F6.3 10+31W e_LX Uncertainty in LX
53- 59 F7.4 --- HR1 ? Hardness ratio HR1 (1)
61- 67 F7.3 --- e_HR1 ? Uncertainty in HR1
69- 76 F8.4 --- HR2 ? Hardness ratio HR2 (1)
78- 84 F7.3 --- e_HR2 ? Uncertainty in HR2
86- 90 F5.3 arcmin DelR Projected distance from galaxy center
92- 95 I4 --- GC ? Globular cluster catalog number given in
Paper II (Humphrey, Cat. J/ApJ/690/512) (2)
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Note (1): Where HR1=(S-M)/(S+M) and HR2=(M-H)/(M+H), and S is the
background subtracted count-rate in the band 0.3-1.5keV, M is the
count-rate in the band 1.5-3.0keV and H corresponds to 3.0-5.0keV.
Note (2): For LMXBs within the appropriate WFPC2 field for which there is a
globular cluster match. If the source has no match, the value is 0
("None" in the paper) and if the source is not in the WFPC2 field, it
is blank. Number identifications given for NGC 1399, 1404, 3115, 3585 and
4494 have to be taken with caution since some of them appear to be very far
from the source.
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History:
From electronic version of the journal
References:
Humphrey P.J. Paper II. 2009ApJ...690..512H 2009ApJ...690..512H Cat. J/ApJ/690/512
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 24-Jan-2011