J/ApJ/600/729 Chandra LMXB in NGC 4649 (Randall+, 2004)
Chandra observation of diffuse gas and low-mass X-ray binaries in the
elliptical galaxy NGC 4649 (M60).
Randall S.W., Sarazin C.L., Irwin J.A.
<Astrophys. J., 600, 729-742 (2004)>
=2004ApJ...600..729R 2004ApJ...600..729R
ADC_Keywords: Binaries, X-ray
Keywords: binaries: close - galaxies: elliptical and lenticular, cD -
galaxies: ISM - X-rays: binaries - X-rays: galaxies - X-rays: ISM
Abstract:
We present a Chandra X-ray observation of the X-ray bright E2
elliptical galaxy NGC 4649. In addition to bright diffuse emission, we
resolve 165 discrete sources, most of which are presumably low-mass
X-ray binaries. As found in previous studies, the luminosity function
of the resolved sources is well-fitted by a broken power law. In
NGC 4697 and NGC 1553, the break luminosity was comparable to the
Eddington luminosity of a 1.4M☉ neutron star.
Description:
NGC 4649 was observed on 2000 April 20 on the ACIS-S3 CCD operated at
a temperature of -120°C and with a frame time of 3.2s. In addition to
the S3 chip, the ACIS chips I2, I3, S1, S2, and S4 were also turned on
for the duration of the observation.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 114 165 Discrete X-Ray sources
--------------------------------------------------------------------------------
See also:
B/chandra : The Chandra Archive Log (CXC, 1999-)
V/113 : Cataclysmic Binaries, LMXBs, & related objects (Ritter+, 2003)
J/ApJ/599/218 : Chandra LMXB in NGC 4365 and NGC 4382 (Sivakoff+, 2003)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 I3 --- [RSI2004] Sequential number
4- 7 A4 --- n_[RSI2004] Note on [RSI2004] (1)
9- 24 A16 --- CXOU CXOU designation (JHHMMSS.s+DDMMSS)
26- 27 I2 h RAh Right ascension (J2000.0)
29- 30 I2 min RAm Right ascension (J2000.0)
32- 36 F5.2 s RAs Right ascension (J2000.0)
38 A1 --- DE- Declination sign (J2000.0)
39- 40 I2 deg DEd Declination (J2000.0)
42- 43 I2 arcmin DEm Declination (J2000.0)
45- 48 F4.1 arcsec DEs Declination (J2000.0)
50- 55 F6.2 arcsec Dist Distance
57- 62 F6.2 10-4s-1 CR Count Rate
64- 68 F5.2 10-4s-1 e_CR rms uncertainty on CR
70- 74 F5.2 --- S/N Signal-to-noise ratio
76- 82 F7.2 10+30W LX X-ray luminosity in the 0.3-10keV band
84- 88 F5.2 --- H21 ? Hardness ratio, (M-S)/(M+S) (2)
90- 93 F4.2 --- E_H21 ? Error on H21 (upper limit)
95- 98 F4.2 --- e_H21 ? Error on H21 (lower limit)
100-104 F5.2 --- H31 ? Hardness ratio, (H-S)/(H+S) (2)
106-109 F4.2 --- E_H31 ? Error on H31 (upper limit)
111-114 F4.2 --- e_H31 ? Error on H31 (lower limit)
--------------------------------------------------------------------------------
Note (1): Individual notes as follows:
a = Source 1 is extended, and appears to be a combination of diffuse
structure with one or more point sources.
b = Positions and count rates of sources near the center of NGC 4649
are uncertain due to the bright diffuse emission and/or
confusion with nearby sources.
c = Globular cluster is possible optical counterpart.
d = Possible faint optical counterpart.
e = Source may be variable.
f = May be associated with the companion galaxy NGC 4647.
g = Source is at the edge of the S3 detector, and flux is uncertain
due to large exposure correction.
h = Possible USNO-A2.0 (I/252) optical counterpart.
Note (2): S, M, and H are the total counts in the soft (0.3-1keV),
medium (1-2keV), and hard (2-10keV) bands, respectively.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) James Marcout, Patricia Vannier [CDS] 13-Feb-2004