J/ApJ/741/49 ULX candidates in nearby galaxies (Swartz+, 2011)
A complete sample of ultraluminous X-ray source host galaxies.
Swartz D.A., Soria R., Tennant A.F., Yukita M.
<Astrophys. J., 741, 49 (2011)>
=2011ApJ...741...49S 2011ApJ...741...49S
ADC_Keywords: Galaxies, nearby ; X-ray sources
Keywords: galaxies: general - surveys - X-rays: binaries - X-rays: galaxies -
X-rays: general
Abstract:
One hundred seven ultraluminous X-ray sources (ULXs) with 0.3-10.0keV
luminosities in excess of 1039erg/s are identified in a complete
sample of 127 nearby galaxies. The sample includes all galaxies within
14.5Mpc above the completeness limits of both the Uppsala Galaxy
Catalogue (Cat. VII/26) and the Infrared Astronomical Satellite survey
(Cat. II/125). The galaxy sample spans all Hubble types, a
four-decade range in mass, 7.5<log(M/M☉)<11.4, and in star
formation rate, 0.0002<SFR(M☉/yr)≤3.6. ULXs are detected in
this sample at rates of one per 3.2x1010M☉, one per
∼0.5M☉/yr star formation rate, and one per 57Mpc3
corresponding to a luminosity density of ∼2x1037erg/s/Mpc3. At
these rates we estimate as many as 19 additional ULXs remain
undetected in fainter dwarf galaxies within the survey volume. An
estimated 14 objects, or 13%, of the 107 ULX candidates are expected
to be background sources. The differential ULX luminosity function
shows a power-law slope α~-0.8 to -2.0 with an exponential
cutoff at ∼20x1039erg/s with precise values depending on the model
and on whether the ULX luminosities are estimated from their observed
numbers of counts or, for a subset of candidates, from their spectral
shapes. Extrapolating the observed luminosity function predicts at
most one very luminous ULX, LX∼1041erg/s, within a distance as
small as 100Mpc. The luminosity distribution of ULXs within the local
universe cannot account for the recent claims of luminosities in
excess of 2x1041erg/s, requiring a new population class to explain
these extreme objects.
Description:
Most of the galaxies in the present sample have been observed with the
Chandra X-Ray Observatory Advanced CCD Imaging Spectrometer (ACIS).
For consistency, Chandra/ACIS data have been used for analysis when
available unless a much deeper XMM-Newton observation exists.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 107 Properties of ULX candidates
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2012)
B/xmm : XMM-Newton Log (XMM-Newton Science Operation Center, 2012)
VII/113 : Catalogued Galaxies + QSOs observed in IRAS Survey, V2 (IPAC 1989)
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
VII/26 : Uppsala General Catalogue of Galaxies (UGC) (Nilson 1973)
J/MNRAS/416/1844 : 2XMM ultraluminous X-ray source candidates (Walton+, 2011)
J/ApJ/687/471 : Observational comparison between ULXs & XRBs (Berghea+, 2008)
J/ApJ/664/458 : Spectral fit of ULX sources (Devi+, 2007)
J/A+A/452/739 : ULX sources and FIRST radio sources (Sanchez-Sutil+, 2006)
J/ApJ/649/730 : ULX population in nearby galaxies from XMM (Winter+, 2006)
J/A+A/429/1125 : Catalog of Ultraluminous X-ray sources (Liu+, 2005)
J/ApJS/157/59 : Ultraluminous X-ray sources in nearby galaxies (Liu+, 2005)
J/ApJS/154/519 : Properties of ultraluminous X-ray candidates (Swartz+, 2004)
J/MNRAS/344/134 : Chandra ultraluminous X-ray sources (Humphrey+, 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 h RAh Hour of right ascension (J2000)
4- 5 I2 min RAm Minute of right ascension (J2000)
7- 11 F5.2 s RAs Second of right ascension (J2000)
13 A1 --- DE- Sign of declination (J2000)
14- 15 I2 deg DEd Degree of declination (J2000)
17- 18 I2 arcmin DEm Arcminute of declination (J2000)
20- 23 F4.1 arcsec DEs Arcsecond of declination (J2000)
25- 32 A8 --- Gal Putative host galaxy name (NGC, IC or UGC number)
34- 37 F4.1 Mpc Dist [3.1/14.5] Putative host galaxy distance
39- 42 F4.2 --- r/D25 [0.01/0.93] Radial position of ULX (1)
44- 53 A10 --- ObsID Observation identifier (Chandra or XMM)
55- 60 F6.1 ct Cts [14/9034]? Detected X-ray source counts (2)
62- 65 F4.1 --- S/N [3.2/82.4]? Signal to noise ratio (2)
67- 70 F4.1 10+32W Lcts [0.2/21.4]? Unabsorbed 0.3-10.0keV luminosity
estimated from source counts in 1039erg/s (3)
72- 75 F4.1 10+32W Lx [1/36]? Unabsorbed 0.3-10.0keV luminosity
estimated from model fits in 1039erg/s (4)
77 I1 --- Ref [1/4]? Reference (5)
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Note (1): Radial position within host galaxy expressed as fraction of D25
radius. See figure 4.
Note (2): Source-finding was applied to events in the 0.3-6.0keV range for
Chandra observations, in the 0.5-4.5keV range for XMM-Newton
observations, and in the full 0.1-2.4keV range for ROSAT observations.
The different ranges were chosen as those that tend to maximize
signal-to-noise ratio (S/N). See section 3.3.
Note (3): Unabsorbed 0.3-10.0keV luminosity estimated from source counts
detected in the 0.3-6.0keV band and assuming an absorbed power-law
spectrum of Γ=1.7 and a Galactic column density.
Note (4): Unabsorbed 0.3-10.0keV luminosity estimated from model fits to the
X-ray spectral energy distribution as given by the references in
Column Ref.
Note (5): Reference as follows:
1 = Feng & Kaaret 2009ApJ...696.1712F 2009ApJ...696.1712F;
2 = Roberts et al. 2004MNRAS.349.1193R 2004MNRAS.349.1193R;
3 = Walton et al. 2011MNRAS.414.1011W 2011MNRAS.414.1011W;
4 = Sutton et al. 2011AN....332..362S 2011AN....332..362S
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History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 20-Feb-2013