J/ApJ/599/1067 X-ray sources in M104 (Di Stefano+, 2003)
X-ray point sources in the Sombrero galaxy: very soft sources, the globular
cluster/low-mass X-ray binary connection, and an overview.
Di Stefano R., Kong A.K.H., Vandalfsen M.L., Harris W.E., Murray S.S.,
Delain K.M.
<Astrophys. J., 599, 1067-1081 (2003)>
=2003ApJ...599.1067D 2003ApJ...599.1067D
ADC_Keywords: X-ray sources ; Clusters, globular ; Binaries, X-ray
Keywords: galaxies: individual (M104) - X-rays: binaries - X-rays: galaxies
Abstract:
We report on the population of point sources discovered during an
18.5ks Chandra ACIS-S observation of the Sombrero galaxy. We present
the luminosity function and the spectra of the six brightest sources,
consider correlations with globular clusters (GCs) and with planetary
nebulae, and study the galaxy's population of very soft sources. We
detected 122 sources. Twenty-two sources are identified as very soft;
of these, five appear to be classical luminous supersoft X-ray sources
(SSSs), while 17 may belong to the slightly harder class referred to
as quasi-soft (QSSs). There is an overdensity of very soft sources
within 2kpc of the nucleus, which is itself the brightest X-ray
source. Very soft sources are also found in the disk and halo, with
one QSS in a globular cluster (GC).
Description:
M104 was observed by Chandra on 2001 May 31 with the Advanced CCD
Imaging Spectrometer (ACIS-S). The effective exposure time was about
18.5ks. In this paper we focus only on the data taken with the
S3 CCD.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 100 122 Source List
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-)
J/MNRAS/327/1116 : VI photometry of Sombrero globular clusters (Larsen+, 2001)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- [DKV2003] Object designation (XNNN)
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 15 F4.1 s RAs Right ascension (J2000.0)
17 A1 --- DE- Declination sign (J2000.0)
18- 19 I2 deg DEd Declination (J2000.0)
21- 22 I2 arcmin DEm Declination (J2000.0)
24- 27 F4.1 arcsec DEs Declination (J2000.0)
29- 33 F5.1 ct Sct Net counts in the soft (0.1-1.1keV) band
35- 38 F4.1 ct e_Sct rms uncertainty on Sct
40- 44 F5.1 ct Mct Net counts in the medium (1.1-2keV) band
46- 49 F4.1 ct e_Mct rms uncertainty on Mct
51- 56 F6.2 ct Hct Net counts in the hard (2-7keV) band
58- 61 F4.1 ct e_Hct rms uncertainty on e_Hct
63- 67 F5.2 10+31W LX X-ray luminosity (1)
69- 72 F4.1 mag Bmag ? B magnitude (from USNO-B1.0, I/284)
74- 77 F4.1 mag Rmag ? R magnitude (from USNO-B1.0, I/284)
79- 82 F4.1 mag Kmag ? K magnitude (from 2 MASS, II/246)
84-100 A17 --- Notes Notes (2)
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Note (1): Luminosity in 0.37keV, assuming d=8.9Mpc, a power-law model
with NH=5x1020cm-2, and α=2 for all sources except SSSs,
for which a blackbody model with NH=5x1020cm-2 and kT=125eV is
applied.
Note (2): Notes:
CFHT: globular clusters from the ground
HST: globular clusters from HST
SSS-HR, SSS-3σ, QSS-HR1, QSS-3σ1, QSS-σ, QSS-FNOH,
and QSS-NOH are for the very soft source category from di Stefano &
Kong (2004, ApJ, submitted).
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History:
From electronic version of the journal
(End) James Marcout, Patricia Bauer [CDS] 20-Feb-2004