J/ApJ/651/1098 Faint X-ray sources in Terzan 5 (Heinke+, 2006)
Faint X-ray sources in the globular cluster Terzan 5.
Heinke C.O., Wijnands R., Cohn H.N., Lugger P.M., Grindlay J.E., Pooley D.,
Lewin W.H.G.
<Astrophys. J., 651, 1098-1111 (2006)>
=2006ApJ...651.1098H 2006ApJ...651.1098H
ADC_Keywords: Clusters, globular ; X-ray sources
Keywords: globular clusters: individual (Terzan 5) -
novae, cataclysmic variables - stars: neutron - X-rays: binaries
Abstract:
We report our analysis of a Chandra X-ray observation of the rich
globular cluster Terzan 5, in which we detect 50 sources to a limiting
1.0-6keV X-ray luminosity of 3x1031ergs/s within the half-mass
radius of the cluster. Thirty-three of these have LX>1032ergs/s, the
largest number yet seen in any globular cluster. In addition to the
quiescent low-mass X-ray binary (LMXB; identified by Wijnands et al.,
2005ApJ...618..883W 2005ApJ...618..883W), another 12 relatively soft sources may be
quiescent LMXBs. We compare the X-ray colors of the harder sources in
Terzan 5 to the Galactic center sources studied by Muno and
collaborators (2003, Cat. J/ApJ/589/225) and find the Galactic
center sources to have harder X-ray colors, indicating a possible
difference in the populations. We cannot clearly identify a
metallicity dependence in the production of low-luminosity X-ray
binaries in Galactic globular clusters, but a metallicity dependence
of the form suggested by Jordan et al. (2004, Cat. J/ApJ/613/270)
for extragalactic LMXBs is consistent with our data.
Description:
We observed Terzan 5 with Chandra for 39.3ks on 2003 July 13-14 using
the Advanced CCD Imaging Spectrometer (ACIS) S3 chip.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 137 50 X-Ray Sources in Terzan 5
table2.dat 121 77 Serendipitous sources in the Terzan 5 field
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See also:
J/A+A/308/733 : NTT VI photometry in Terzan 5 (Ortolani+ 1996)
J/ApJ/589/225 : Chandra X-ray sources toward Galactic Center (Feigelson+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- CX [1/50] CX (Chandra) number,
[HWC2006] CX NN in Simbad
4- 18 A15 --- CXOGlbJ CXOGlbJ name (HHMMSS.s+DDMMSS),
CXOGlb JHHMMSS.s+DDMMSS in Simbad
20- 21 I2 h RAh Right ascension (J2000)
23- 24 I2 min RAm Right ascension (J2000)
26- 31 F6.3 s RAs Right ascension (J2000)
33- 37 F5.3 s e_RAs rms uncertainty on RA
39 A1 --- DE- Declination sign (J2000)
40- 41 I2 deg DEd Declination (J2000)
43- 44 I2 arcmin DEm Declination (J2000)
46- 50 F5.2 arcsec DEs Declination (J2000)
52- 55 F4.2 arcsec e_DEs rms uncertainty on DE
57- 61 F5.2 arcsec Dist Distance from the center of Terzan 5
63- 67 F5.1 ct C(0.5-2) Counts in 0.5-2keV band
69- 72 F4.1 ct E_C(0.5-2) Error on C(0.5-2keV) (upper limit)
74- 77 F4.1 ct e_C(0.5-2) Error on C(0.5-2keV) (lower limit)
79- 83 F5.1 ct C(2-6) Counts in 2-6keV band
85- 88 F4.1 ct E_C(2-6) Error on C(2-6keV) (upper limit)
90- 93 F4.1 ct e_C(2-6) Error on C(2-6keV) (lower limit)
95- 98 I4 10+23W LX(1-6) X-ray luminosity in the 1-6keV band
100-102 I3 10+23W E_LX(1-6) Error on LX(1-6keV) (upper limit)
104-106 I3 10+23W e_LX(1-6) Error on LX(1-6keV) (lower limit)
108-111 I4 10+23W LX(0.5-2.5) X-ray luminosity in the 0.5-2.5keV band
113-116 I4 10+23W E_LX(0.5-2.5) Error on LX(0.5-2.5keV) (upper limit)
118-120 I3 10+23W e_LX(0.5-2.5) Error on LX(0.5-2.5keV) (lower limit)
122-124 A3 --- [HEG2003] Heinke et al. (2003ApJ...590..809H 2003ApJ...590..809H)
designation
126-137 A12 --- Notes Notes (1)
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Note (1): Notes as follows:
V = short-term variability (99% confidence)
V? = short-term variability (95% confidence)
Y = variability on timescales of years between 2000 and 2003
L = possible transient LMXB EXO 1745-248
q = possible qLMXB
q? = possible qLMXB candidate
s = possible foreground star
MSP = possible radio millisecond pulsar
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 15 A15 --- CXOGlbJ CXOGlbJ name (HHMMSS.s+DDMMSS),
CXOGlb JHHMMSS.s+DDMMSS in Simbad
17- 18 I2 h RAh Right ascension (J2000)
20- 21 I2 min RAm Right ascension (J2000)
23- 28 F6.3 s RAs Right ascension (J2000)
30- 34 F5.3 s e_RAs rms uncertainty on RA
36 A1 --- DE- Declination sign (J2000)
37- 38 I2 deg DEd Declination (J2000)
40- 41 I2 arcmin DEm Declination (J2000)
43- 47 F5.2 arcsec DEs Declination (J2000)
49- 52 F4.2 arcsec e_DEs rms uncertainty on DE
54- 59 F6.2 arcsec Dist Distance from the center of Terzan 5
61- 64 F4.1 ct C(0.5-2) Counts in 0.5-2keV band
66- 69 F4.1 ct E_C(0.5-2) Error on C(0.5-2keV) (upper limit)
71- 73 F3.1 ct e_C(0.5-2) Error on C(0.5-2keV) (lower limit)
75- 78 F4.1 ct C(2-6) Counts in 2-6keV band
80- 82 F3.1 ct E_C(2-6) Error on C(2-6keV) (upper limit)
84- 86 F3.1 ct e_C(2-6) Error on C(2-6keV) (lower limit)
88- 91 F4.1 aW/m2 F(0.5-6) X-ray flux in the 0.5-6keV band (1)
93- 96 F4.1 aW/m2 E_F(0.5-6) Error on F(0.5-6keV) (upper limit)
98-101 F4.1 aW/m2 e_F(0.5-6) Error on F(0.5-6keV) (lower limit)
103 A1 --- Notes [c?] Likely optical counterparts (c) or
less likely counterparts (?)
104 A1 --- Flag [*] source used to align X-ray positions
106-110 F5.2 mag Bmag ? B magnitude (2)
112-115 F4.1 mag Rmag ? R magnitude (2)
117-121 F5.2 mag Imag ? I magnitude (2)
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Note (1): Assuming NH=1.2x1022cm-2
Note (2): Magnitudes are from the USNO-B1.0 digitized sky survey (Monet et
al., 2003, Cat. I/284), averaged when two measurements exist; note
that there is substantial scatter among these measurements (up to
1mag), presumably due to crowding.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 23-Jul-2008