J/AJ/143/144 ULX candidates in nearby Arp galaxies (Smith+, 2012)
ChAInGeS: the Chandra Arp Interacting Galaxies Survey.
Smith B.J., Swartz D.A., Miller O., Burleson J.A., Nowak M.A., Struck C.
<Astron. J., 143, 144 (2012)>
=2012AJ....143..144S 2012AJ....143..144S
ADC_Keywords: X-ray sources ; Galaxies, IR ; Galaxies, nearby ; Spectral types
Keywords: galaxies: interactions - galaxies: starburst - ultraviolet: galaxies -
X-rays: galaxies
Abstract:
We have conducted a statistical analysis of the ultra-luminous X-ray
point sources (ULXs; LX≥1039erg/s) in a sample of galaxies
selected from the Arp Atlas of Peculiar Galaxies (1996, Cat. VII/192;
Webb, 1996, Cat. VII/192). We find a possible enhancement of a factor
of ∼2-4 in the number of ULXs per blue luminosity for the strongly
interacting subset. Such an enhancement would be expected if ULX
production is related to star formation, as interacting galaxies tend
to have enhanced star formation rates on average. For most of the Arp
galaxies in our sample, the total number of ULXs compared to the
far-infrared luminosity is consistent with values found earlier for
spiral galaxies. This suggests that for these galaxies, ULXs trace
recent star formation. However, for the most infrared-luminous
galaxies, we find a deficiency of ULXs compared to the infrared
luminosity. For these very infrared-luminous galaxies, active galactic
nuclei may contribute to powering the far-infrared; alternatively,
ULXs may be highly obscured in the X-ray in these galaxies and
therefore not detected by these Chandra observations. We determined
local UV/optical colors within the galaxies in the vicinity of the
candidate ULXs using Galaxy Evolution Explorer UV and Sloan Digitized
Sky Survey optical images. In most cases, the distributions of colors
are similar to the global colors of interacting galaxies. However, the
u-g and r-i colors at the ULX locations tend to be bluer on average
than these global colors, suggesting that ULXs are preferentially
found in regions with young stellar populations. In the Arp sample
there is a possible enhancement of a factor of ∼2-5 in the fraction of
galactic nuclei that are X-ray-bright compared to more normal spirals.
Description:
We selected a set of 45 peculiar galaxy systems from the Arp Atlas of
Peculiar Galaxies (Arp, 1966, Cat. VII/74; Webb, 1996, Cat. VII/192)
having both Chandra/ACIS (Chandra X-Ray Observatory Advanced CCD
Imaging Spectrometer) X-ray and SDSS-DR7 optical images.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 121 45 Interacting galaxy sample for ULX study and
available chandra data
table2.dat 50 97 List of ULX candidates and nuclear X-ray sources
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2013)
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
VII/74 : Atlas of Peculiar Galaxies (Arp 1966): redshifts
VII/192 : Arp's Peculiar Galaxies (Webb 1996)
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
J/ApJ/741/49 : ULX candidates in nearby galaxies (Swartz+, 2011)
J/AJ/140/1975 : Normal spiral galaxies optical & UV photometry (Smith+, 2010)
J/AJ/139/1212 : SDSS photometry of interacting galaxies (Smith+, 2010)
J/ApJ/687/471 : Observational comparison between ULXs & XRBs (Berghea+, 2008)
J/ApJ/664/458 : Spectral fit of ULX sources (Devi+, 2007)
J/AJ/133/791 : Spitzer phot. of normal & interacting galaxies (Smith+, 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/AJ/127/3235 : HIRES atlas of all RBGS galaxies (Surace+, 2004)
J/ApJS/154/519 : Properties of ultraluminous X-ray candidates (Swartz+, 2004)
J/A+A/422/941 : Gas content in 1038 interacting galaxies (Casasola+, 2004)
J/MNRAS/344/134 : Chandra ultraluminous X-ray sources (Humphrey+, 2003)
http://ned.ipac.caltech.edu/level5/Arp/frames.html : On-line Arp atlas of
peculiar galaxies
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [Arp]
5- 7 I3 --- Arp Arp system number
9 A1 --- f_Arp Flag on Name (e=In the strongly interacting
subset; see Section 6)
11- 27 A17 --- Gal Observed galaxy name (1)
29- 43 A15 --- SpT Nuclear spectral type
45- 46 I2 h RAh Hour of Right Ascension (J2000)
48- 49 I2 min RAm Minute of Right Ascension (J2000)
51- 54 F4.1 s RAs Second of Right Ascension (J2000)
56 A1 --- DE- Sign of the Declination
57- 58 I2 deg DEd Degree of Declination (J2000)
60- 61 I2 arcmin DEm Arcminute of Declination (J2000)
63- 64 I2 arcsec DEs Arcsecond of Declination (J2000)
66- 70 F5.1 Mpc Dist [3.9/129] Distance (2)
72- 78 A7 arcmin Diam [0-9.* ] Angular diameter (3)
80 A1 --- l_logLFIR Upper limit on logLFIR
81- 85 F5.2 [Lsun] logLFIR [7.98/12.03]? Log of total 42.4-122.5µm
far-infrared luminosity (logLFIR)
87 A1 --- f_logLFIR [d] Flag on LFIR (d=in the IRAS
sample; see Section 7)
89- 92 F4.1 ks ChExp Chandra exposure time
94- 98 F5.2 [10-7W] log(Lx) [36.98/39.98] Log of the 0.5-8keV X-ray
point-source luminosity detection limit
corresponding to the Chandra exposure
time (LX limit) (in units of erg/s)
100-105 A6 --- Array Chandra array (ACIS-I or ACIS-S)
107-111 I5 --- Set Chandra data set number
113-116 I4 s ExpFUV ? GALEX FUV exposure time
118-121 I4 s ExpNUV ? GALEX NUV exposure time
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Note (1): There are a total of 69 individual galaxies in the 45 Arp systems
that are covered at least in part by the Chandra S3 or I array field
of view.
Note (2): From the NASA Extragalactic Database (NED), using, as a first
preference, the mean of the distance-independent determinations, and
as a second choice, H0=73km/s/Mpc, with Virgo, Great Attractor, and
SA infall models.
Note (3): Total angular extent of Arp system. From NASA Extragalactic
Database (NED), when available; otherwise, estimated from the SDSS
images or the Digital Sky Survey images available from NED.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- --- [Arp]
5- 7 I3 --- Arp Arp system number
9- 15 A7 --- Loc X-ray sources location relative to optical
features (disk, nuclear or tidal)
(see section 3.2 for more details)
17- 36 A20 --- CXO CXO name (JHHMMSS.s+DDMMSS) (1)
38- 42 F5.1 10+32W Lx [1/296.9] 0.5-8keV X-ray luminosities
(in 1039erg/s)
44- 46 A3 --- Srce Optical source? ("yes" or blank)
48- 50 A3 --- Sample Sample (I or S) (2)
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Note (1): Sources labeled "new" are not in the current version of the
Chandra Source Catalog (2010ApJS..189...37E 2010ApJS..189...37E).
Note (2): Because of the range in the sensitivities of the archival
observations we are using, we divide the sample of galaxies into two
subsets, see section 3.3 for further details. The samples are:
I = in the intermediate sample (the original set of 45 Arp systems);
S = in the sensitive sample (the subset of 25 Arp systems with
sensitivities≤1039erg/s.
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 17-Jul-2013