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Spitzer Space Telescope IRAC and MIPS observations of the interacting galaxies IC 2163 and NGC 2207 : clumpy emission

Elmegreen, Debra Meloy and Elmegreen, Bruce G. and Kaufman, Michele and Sheth, Kartik and Struck, Curtis and Thomasson, Magnus and Brinks, Elias (2006) Spitzer Space Telescope IRAC and MIPS observations of the interacting galaxies IC 2163 and NGC 2207 : clumpy emission. Astrophysical Journal, 642 (1). pp. 158-170. ISSN 0004-637X.

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IC 2163 and NGC 2207 are interacting galaxies that have been well studied at optical and radio wavelengths and simulated in numerical models to reproduce the observed kinematics and morphological features. Spitzer IRAC and MIPS observations reported here show over 200 bright clumps from young star complexes. The brightest IR clump is a morphologically peculiar region of star formation in the western arm of NGC 2207. This clump, which dominates the Hα and radio continuum emission from both galaxies, accounts for ~12% of the total 24 μm flux. Nearly half of the clumps are regularly spaced along some filamentary structure, whether in the starburst oval of IC 2163 or in the thin spiral arms of NGC 2207. This regularity appears to influence the clump luminosity function, making it peaked at a value nearly a factor of 10 above the completeness limit, particularly in the starburst oval. This is unlike the optical clusters inside the clumps, which have a luminosity function consistent with the usual power-law form. The giant IR clumps presumably formed by gravitational instabilities in the compressed gas of the oval and the spiral arms, whereas the individual clusters formed by more chaotic processes, such as turbulence compression, inside these larger scale structures.

Item Type:Article
Related URLs:
URLURL TypeDescription
Elmegreen, Debra Meloy0000-0002-1392-3520
Elmegreen, Bruce G.0000-0002-1723-6330
Sheth, Kartik0000-0002-5496-4118
Struck, Curtis0000-0002-6490-2156
Brinks, Elias0000-0002-7758-9699
Additional Information:© 2006 The American Astronomical Society. Received 2005 October 17; accepted 2005 December 29. We gratefully acknowledge support from NASA JPL/Spitzer grant RSA 1264471 to M. K. and RSA 1264582 to D. M. E. for Cycle 1 observations. We thank Bev Smith for helpful discussions and an anonymous referee for useful comments. Deidre Hunter kindly provided the Hα image, based on observations at Lowell Observatory.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NASA JPL/SpitzerRSA 1264471
NASA JPL/SpitzerRSA 1264582
Subject Keywords:galaxies: individual (IC 2163, NGC 2207); galaxies: interactions; infrared: galaxies
Issue or Number:1
Record Number:CaltechAUTHORS:ELMapj06
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13742
Deposited By: Tony Diaz
Deposited On:13 Jul 2009 16:15
Last Modified:09 Mar 2020 13:18

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