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Title: NGC 2207/IC 2163: A GRAZING ENCOUNTER WITH LARGE-SCALE SHOCKS

Abstract

Radio continuum, Spitzer infrared, optical, and XMM-Newton X-ray and ultraviolet observations (UVW1 and UVM2) are used to study large-scale shock fronts, young star complexes, and the galactic nuclei in the interacting galaxies NGC 2207/IC 2163. There are two types of large-scale shock fronts in this galaxy pair. The large-scale shock front along the rim of the ocular oval in IC 2163 has produced vigorous star formation in a dusty environment, bright in the Spitzer 8 {mu}m and 24 {mu}m images. In the outer part of the companion side of NGC 2207, a large-scale front attributed to halo scraping is particularly bright in the {lambda}6 cm and {lambda}20 cm radio continuum but not in any tracers of recent star formation (H{alpha}, 8 {mu}m, 24 {mu}m, or ultraviolet emission) or in X-rays. This radio-continuum front may be from compression of the halo magnetic field on the back side of NGC 2207, between the two galaxies. The X-ray emission sets an upper limit to the gas density in the halo. Values of the flux density ratio S{sub {nu}}(8 {mu}m)/S{sub {nu}}(6 cm) of prominent, kiloparsec-size, Spitzer/IRAC star-forming clumps in NGC 2207/IC 2163 are compared with those of giant radio H II regions in M81.more » For the bright clumps in NGC 2207, the mean value of this ratio is the same as for the M81 H II regions, whereas for the bright clumps on the rim of the IC 2163 ocular oval, the mean value is nearly a factor of two greater. Possible explanations for this are discussed. The galaxy pair has global values of the ratios of infrared-to-radio continuum flux density in the Spitzer 8 {mu}m, 24 {mu}m, and 70 {mu}m bands, and the IRAS FIR significantly below the medians/means for large samples of galaxies. Feature i, a mini-starburst on an outer arm of NGC 2207 on its anti-companion side, is the most luminous 8 {mu}m, 24 {mu}m, 70 {mu}m, radio continuum, and H{alpha} source in the galaxy pair. We find evidence that a radio supernova was present in the core of feature i in 2001. X-ray emission is detected from the nucleus of NGC 2207 and from nine discrete sources whose X-ray luminosities make them possible candidates for Ultraluminous X-ray sources. One of these corresponds with the Type Ib SN 1999ec, which is also bright in the ultraviolet, and another may be a radio supernova or a background quasar. The X-ray luminosity of the NGC 2207 nucleus is log L{sub 0.3-10.0keV} = 40.6 erg s{sup -1}, which, together with its X-ray spectrum, suggests that this is a highly absorbed, low-luminosity, active galactic nucleus.« less

Authors:
 [1];  [2];  [3];  [4];  [5];  [6]
  1. Department of Physics, Ohio State University, 191 West Woodruff Ave, Columbus, OH 43210 (United States)
  2. Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)
  3. IBM Research Division, T. J. Watson Research Center, P.O. Box 218, Yorktown Heights, NY 10598 (United States)
  4. Department of Physics and Astronomy, Vassar College, 124 Raymond Ave., Poughkeepsie, NY 12604 (United States)
  5. Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States)
  6. Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom)
Publication Date:
OSTI Identifier:
22089817
Resource Type:
Journal Article
Journal Name:
Astronomical Journal (New York, N.Y. Online)
Additional Journal Information:
Journal Volume: 144; Journal Issue: 5; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-3881
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; DENSITY; FLUX DENSITY; GALAXY NUCLEI; GAMMA ASTRONOMY; LUMINOSITY; MAGNETIC FIELDS; QUASARS; SUPERNOVAE; ULTRAVIOLET RADIATION; X RADIATION; X-RAY GALAXIES; X-RAY SPECTRA

Citation Formats

Kaufman, Michele, Grupe, Dirk, Elmegreen, Bruce G., Elmegreen, Debra M., Struck, Curtis, and Brinks, Elias, E-mail: rallis.1@osu.edu, E-mail: dxg35@psu.edu, E-mail: bge@us.ibm.com, E-mail: elmegreen@vassar.edu, E-mail: curt@iastate.edu, E-mail: E.Brinks@herts.ac.uk. NGC 2207/IC 2163: A GRAZING ENCOUNTER WITH LARGE-SCALE SHOCKS. United States: N. p., 2012. Web. doi:10.1088/0004-6256/144/5/156.
Kaufman, Michele, Grupe, Dirk, Elmegreen, Bruce G., Elmegreen, Debra M., Struck, Curtis, & Brinks, Elias, E-mail: rallis.1@osu.edu, E-mail: dxg35@psu.edu, E-mail: bge@us.ibm.com, E-mail: elmegreen@vassar.edu, E-mail: curt@iastate.edu, E-mail: E.Brinks@herts.ac.uk. NGC 2207/IC 2163: A GRAZING ENCOUNTER WITH LARGE-SCALE SHOCKS. United States. doi:10.1088/0004-6256/144/5/156.
Kaufman, Michele, Grupe, Dirk, Elmegreen, Bruce G., Elmegreen, Debra M., Struck, Curtis, and Brinks, Elias, E-mail: rallis.1@osu.edu, E-mail: dxg35@psu.edu, E-mail: bge@us.ibm.com, E-mail: elmegreen@vassar.edu, E-mail: curt@iastate.edu, E-mail: E.Brinks@herts.ac.uk. Thu . "NGC 2207/IC 2163: A GRAZING ENCOUNTER WITH LARGE-SCALE SHOCKS". United States. doi:10.1088/0004-6256/144/5/156.
@article{osti_22089817,
title = {NGC 2207/IC 2163: A GRAZING ENCOUNTER WITH LARGE-SCALE SHOCKS},
author = {Kaufman, Michele and Grupe, Dirk and Elmegreen, Bruce G. and Elmegreen, Debra M. and Struck, Curtis and Brinks, Elias, E-mail: rallis.1@osu.edu, E-mail: dxg35@psu.edu, E-mail: bge@us.ibm.com, E-mail: elmegreen@vassar.edu, E-mail: curt@iastate.edu, E-mail: E.Brinks@herts.ac.uk},
abstractNote = {Radio continuum, Spitzer infrared, optical, and XMM-Newton X-ray and ultraviolet observations (UVW1 and UVM2) are used to study large-scale shock fronts, young star complexes, and the galactic nuclei in the interacting galaxies NGC 2207/IC 2163. There are two types of large-scale shock fronts in this galaxy pair. The large-scale shock front along the rim of the ocular oval in IC 2163 has produced vigorous star formation in a dusty environment, bright in the Spitzer 8 {mu}m and 24 {mu}m images. In the outer part of the companion side of NGC 2207, a large-scale front attributed to halo scraping is particularly bright in the {lambda}6 cm and {lambda}20 cm radio continuum but not in any tracers of recent star formation (H{alpha}, 8 {mu}m, 24 {mu}m, or ultraviolet emission) or in X-rays. This radio-continuum front may be from compression of the halo magnetic field on the back side of NGC 2207, between the two galaxies. The X-ray emission sets an upper limit to the gas density in the halo. Values of the flux density ratio S{sub {nu}}(8 {mu}m)/S{sub {nu}}(6 cm) of prominent, kiloparsec-size, Spitzer/IRAC star-forming clumps in NGC 2207/IC 2163 are compared with those of giant radio H II regions in M81. For the bright clumps in NGC 2207, the mean value of this ratio is the same as for the M81 H II regions, whereas for the bright clumps on the rim of the IC 2163 ocular oval, the mean value is nearly a factor of two greater. Possible explanations for this are discussed. The galaxy pair has global values of the ratios of infrared-to-radio continuum flux density in the Spitzer 8 {mu}m, 24 {mu}m, and 70 {mu}m bands, and the IRAS FIR significantly below the medians/means for large samples of galaxies. Feature i, a mini-starburst on an outer arm of NGC 2207 on its anti-companion side, is the most luminous 8 {mu}m, 24 {mu}m, 70 {mu}m, radio continuum, and H{alpha} source in the galaxy pair. We find evidence that a radio supernova was present in the core of feature i in 2001. X-ray emission is detected from the nucleus of NGC 2207 and from nine discrete sources whose X-ray luminosities make them possible candidates for Ultraluminous X-ray sources. One of these corresponds with the Type Ib SN 1999ec, which is also bright in the ultraviolet, and another may be a radio supernova or a background quasar. The X-ray luminosity of the NGC 2207 nucleus is log L{sub 0.3-10.0keV} = 40.6 erg s{sup -1}, which, together with its X-ray spectrum, suggests that this is a highly absorbed, low-luminosity, active galactic nucleus.},
doi = {10.1088/0004-6256/144/5/156},
journal = {Astronomical Journal (New York, N.Y. Online)},
issn = {1538-3881},
number = 5,
volume = 144,
place = {United States},
year = {2012},
month = {11}
}