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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[12.07] The Infrared Properties of Dwarf Galaxies: New Results from SINGS and THINGS

J. M. Cannon, F. Walter (Max-Planck-Institute for Astronomy, Heidelberg), R. C. Kennicutt, G. Bendo (University of Arizona), E. Brinks (University of Hertfordshire), D. Calzetti (Space Telescope Science Institute), W.J.G. de Blok (Australian National University), C. Engelbracht, K.D. Gordon (University of Arizona), L. Kewley (Harvard-Smithsonian Center for Astrophysics), A. Li (University of Arizona), M. Meyer, M. Regan (Space Telescope Science Institute), H. Roussel (Spitzer Science Center), J.D.T. Smith (University of Arizona), M. Thornley (Bucknell University)

We present new observations of dwarf galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS) Legacy Program dataset. The unprecedented sensitivity of these data offers a unique opportunity for a detailed exploration of the properties of these faint systems in the infrared. We compare these data to sensitive HI observations obtained in The HI Nearby Galaxies Survey ( THINGS) to study the correlation between local gas density and PAH and dust emission. PAH emission is detected in all systems that are actively forming stars, while more quiescent systems show no diffuse emission in the 7.7 micron PAH band. The sensitive MIPS data show warm dust in most galaxies, including two systems with abundances ~ 10% of the solar value. Using model fitting to the far-infrared spectral energy distributions, we investigate the characteristics of the dust and PAH emission in the M81 group dwarfs Holmberg II and IC 2574, and in the dwarf galaxies NGC 1705 and NGC 6822. These results are important for understanding the nature of star formation and the heating and cooling processes in the low-metallicity dwarf galaxy interstellar medium.

Support for this work, part of the Spitzer Space Telescope Legacy Science Program ``The Spitzer Nearby Galaxies Survey'', was provided by NASA through contract 1224769 issued by JPL/Caltech under NASA contract 1407.

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