J/ApJ/797/91 X-Ray source properties for NGC 2207/IC 2163 (Mineo+, 2014)
A comprehensive X-ray and multiwavelength study of the colliding galaxy pair
NGC 2207/IC 2163.
Mineo S., Rappaport S., Levine A., Pooley D., Steinhorn B., Homan J.
<Astrophys. J., 797, 91 (2014)>
=2014ApJ...797...91M 2014ApJ...797...91M (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Binaries, X-ray
Keywords: dust, extinction - galaxies: individual: NGC 2207/IC2163 -
galaxies: interactions - galaxies: starburst - stars: formation -
stars: luminosity function, mass function - stars: neutron -
X-rays: binaries - X-rays: ISM
Abstract:
We present a comprehensive study of the total X-ray emission from the
colliding galaxy pair NGC 2207/IC 2163, based on Chandra, Spitzer, and
GALEX data. We detect 28 ultraluminous X-ray sources (ULXs), 7 of
which were not detected previously because of X-ray variability.
Twelve sources show significant long-term variability, with no
correlated spectral changes. Seven sources are transient candidates.
One ULX coincides with an extremely blue star cluster (B-V=-0.7).
We confirm that the global relation between the number and luminosity
of ULXs and the integrated star-formation rate (SFR) of the host
galaxy also holds on local scales. We investigate the effects of dust
extinction and age on the X-ray binary (XRB) population on subgalactic
scales. The distributions of NX and LX are peaked at LIR/LNUV∼1,
which may be associated with an age of ∼10 Myr for the underlying
stellar population. We find that approximately one-third of the XRBs
are located in close proximity to young star complexes. The luminosity
function of the XRBs is consistent with that typical for high-mass
XRBs and appears unaffected by variability. We disentangle and compare
the X-ray diffuse spectrum with that of the bright XRBs. The hot
interstellar medium dominates the diffuse X-ray emission at E≲1 keV
and has a temperature kT=0.28-0.04+0.05 keV and intrinsic 0.5-2 keV
luminosity of 7.9x1040 erg/s, a factor of ∼2.3 higher than the
average thermal luminosity produced per unit SFR in local star-forming
galaxies. The total X-ray output of NGC 2207/IC 2163 is 1.5x1041 erg/s,
and the corresponding total integrated SFR is 23.7 M☉/yr.
Description:
We analyzed four Chandra ACIS-S observations of the galaxy pair
NGC 2207/IC 2163. The data reduction was done following the standard
CIAO threads (CIAO version 4.6, CALDB version 4.5.9) for soft (0.5-2 keV),
hard (2-8 keV), and broad (0.5-8.0 keV) energy bands. All Chandra
data sets were reprocessed using chandra_repro, a script that
automates the recommended data-processing steps presented in the CIAO
analysis threads. Using the script fluximage, we computed a
monochromatic exposure map for the mean photon energy of each band:
1.25 keV, 5.0 keV, and 4.25 keV for the soft, hard, and broad band,
respectively. fluximage outputs both the instrument map for the center
of each energy band using the tool mkinstmap and the exposure maps in
sky coordinates for each energy band using mkexpmap.
Objects:
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RA (ICRS) DE Designation(s)
-----------------------------------------------------------------
06 16 22.09 -21 22 21.8 NGC 2207 = IRAS F06142-2121
06 16 28.01 -21 22 33.1 IC 2163 = 2MASX J06162800-2122330
-----------------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table7.dat 92 34 NGC 2207/IC2163: X-Ray Source Properties for
ObsID 11228 (2010/07/18)
table8.dat 92 40 NGC 2207/IC2163: X-Ray Source Properties for
ObsID 14914 (2012/12/30)
table9.dat 92 32 NGC 2207/IC2163: X-Ray Source Properties for
ObsID 14799 (2013/04/07)
table10.dat 92 41 NGC 2207/IC2163: X-Ray Source Properties for
ObsID 14915 (2013/08/24)
table11.dat 92 74 NGC 2207/IC2163: X-Ray Source Properties for
the Combined Image
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See also:
J/AJ/121/182 : Photometry of Clusters in IC2163 and NGC2207 (Elmegreen+, 2001)
J/ApJ/642/158 : IRAC flux densities in IC2163 and NGC2207 (Elmegreen+, 2006)
J/AJ/133/220 : X-ray sources in galaxy pairs (Gruetzbauch+, 2007)
J/ApJ/741/49 : ULX candidates in nearby galaxies (Swartz+, 2011)
Byte-by-byte Description of file: table[789].dat table1[01].dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Source [1/74] Source number
3 A1 --- n_Source [D+*-/,] Note on Source (1)
5- 12 F8.5 deg RAdeg Right Ascension in decimal degrees (J2000)
14- 21 F8.4 deg DEdeg Declination in decimal degrees (J2000)
23- 27 F5.1 ct Count1 Net counts in broad (0.5-8 keV) band
29- 32 F4.1 ct e_Count1 Uncertainty in Count1 (2)
34- 37 F4.1 --- Signi Broadband source detection significance from
wavdetect (3)
39- 43 F5.1 ct Count2 Net counts in soft (0.5-2 keV) band
45- 48 F4.1 ct e_Count2 Uncertainty in Count2 (4)
50- 55 F6.2 ct Count3 Net counts in hard (2-8 keV) band
57- 60 F4.1 ct e_Count3 Uncertainty in Count3 (4)
62- 66 F5.2 --- HR Hardness ratio (5)
68- 71 F4.2 --- e_HR Uncertainty in HR (6)
73- 77 F5.1 10+31W LX X-ray luminosity in the 0.5-8 keV band
(1038 erg/s)
79- 82 F4.1 10+31W e_LX Uncertainty in LX
84- 87 F4.2 10-17W/m2 FX X-ray flux in the 0.5-8 keV band
(10-14 erg/cm2/s)
89- 92 F4.2 10-17W/m2 e_FX Uncertainty in FX
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Note (1): Note as follows:
D = Extended soft X-ray source;
+ = Central active galactic nucleus;
* = SN 2003H (3.1" match);
- = SN 2013ai (0.23" match);
/ = SN 2013ai (0.12" match);
, = SN 1999ec (4.2" match).
Note (2): The uncertainty expressed here takes into account the fluctuations in
the source as well as in the background.
Note (3): This computes how unlikely it is for the background in the customized
PSF region to fluctuate to yield the detected number of counts. Note
that the PSF region is optimized differently in wavdetect than in the
calculation of column (4) and is typically larger than in the latter.
Note (4): Uncertainties in net counts are quoted to 1σ.
Note (5): Computed with Equation (1) : HR=H-S/H+S.
Note (6): Uncertainties were obtained by applying error propagation to the
uncertainties in the net counts.
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History:
From electronic version of the journal
(End) Prepared by Tiphaine Pouvreau [CDS] 16-Aug-2017