A comprehensive X-ray and multiwavelength study of the Colliding Galaxy Pair NGC2207/IC2163

Abstract

We present a comprehensive study of the total X-ray emission from the colliding galaxy pair NGC2207/IC2163, based on Chandra, Spitzer, and GALEX data. We detect 28 ultra-luminous X-ray sources (ULXs), 7 of which were not detected previously due to 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/or age on the X-ray binary (XRB) population on sub-galactic scales. The distributions of Nx and Lx are peaked at L(IR)/L(NUV)~1, which may be associated with an age of ~10 Myr for the underlying stellar population. We find that ~1/3 of the XRBs are located in close proximity to young star complexes. The luminosity function of the X-ray binaries is consistent with that typical for high-mass X-ray binaries, 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, has a temperature kT=0.28 (+0.05/-0.04) keV and intrinsic 0.5-2 keV luminosity of 7.9e+40 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 NGC2207/IC2163 is 1.5e+41 erg/s, and the corresponding total integrated SFR is 23.7 Msol/yr.

24 pages, 11 figures, 11 tables. Accepted for publication in The Astrophysical Journal

References in corpus (15)

• An Ultraluminous X-ray Source Powered by An Accreting Neutron Star
• Catalogue of high-mass X-ray binaries in the Galaxy ($4^{th}$ edition)
• A new method for determining the sensitivity of X-ray imaging observations and the X-ray number counts
• X-ray binary formation in low-metallicity blue compact dwarf galaxies
• Estimating the total infrared luminosity of galaxies up to z~2 from mid- and far-infrared observations
• Ultraviolet through Infrared Spectral Energy Distributions from 1000 SDSS Galaxies: Dust Attenuation
• The ultraluminous X-ray source NGC 1313 X-2 - Its optical counterpart and environment
• IRAC and MIPS Observations of the Interacting Galaxies IC 2163 and NGC 2207: Clumpy Emission
• Optical emission from massive donors in ULX binary systems
• Cumulative hard X-ray spectrum of local AGN: a link to the cosmic X-ray background
• Models for the Observable System Parameters of Ultraluminous X-ray Sources
• Near-infrared counterparts of ultraluminous X-ray sources
• The Long-Term Variability of the X-Ray Sources in NGC 6946 and NGC 4485/4490
• On the compact nature of the most luminous ULX in the Cartwheel ring
• A deficit of ultraluminous X-ray sources in luminous infrared galaxies

Cited by in corpus (4)

• Chandra ACIS Survey of X-ray Point Sources in Nearby Galaxies. II. X-ray Luminosity Functions and Ultraluminous X-ray Sources
• The Stellar Age Dependence of X-ray Emission from Normal Star-Forming Galaxies in the GOODS Fields
• Ocular Shock Front in the Colliding Galaxy IC 2163
• The largest bright ULX population in a galaxy: X-ray variability and Luminosity Function in the Cartwheel ring Galaxy