AAS 206th Meeting, 29 May - 2 June 2005
Session 12 Dwarf Irregular and Starburst Galaxies
Poster, Monday, 9:20am-6:30pm, Tuesday, 10:00am-7:00pm, May 30, 2005, Ballroom A

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[12.06] Using Spitzer Infrared Colors as Diagnostics of Star Forming Regions in the Interacting Galaxies Arp 107 and Arp 82

B. J. Smith (ETSU), C. Struck (ISU), P. N. Appleton (SSC), V. Charmandaris (Univ. Crete/Cornell), W. Reach (SSC)

We present Spitzer infrared color-color plots for clumps in the vicinities of the interacting galaxies Arp 107 and Arp 82. Using these colors and comparing with optical data from the SARA telescope, we are able to distinguish background quasars and foreground stars from star forming regions associated with the galaxies. For the star forming regions, the [5.8 micron] - [8.0 micron] color remains approximately constant while the [4.5 micron] - [5.8 micron] color varies from clump to clump. This suggests that the 5.8 and 8.0 micron bands are dominated by emission from small interstellar dust grains, and the strength of the PAH 7.7 micron feature relative to the dust continuum does not vary much with interstellar radiation field strength within these galaxies. The [4.5] - [5.8] color is a measure of the relative amount of young stars to old stars, with a redder color indicating a higher proportion of young stars. We present preliminary numerical simulations of the interactions, and discuss star formation triggering mechanisms in these systems. This research is supported by NSF grant AST-0097616 and NASA Spitzer grant 1263924.

The author(s) of this abstract have provided an email address for comments about the abstract: smithbj@etsu.edu

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Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.