AAS 204th Meeting, June 2004
Session 41 Spitzer Space Telescope
Topical Related Poster, Tuesday, June 1, 2004, 10:00am-7:00pm, Ballroom

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[41.18] Infrared Discovery of New HII regions and a possible supernova remnant in the Spitzer Galactic First Look Survey

J. Rho, S. Carey, W. T. Reach, T. Pannuti, M. J. Burgdorf, S. B. Fajardo-Acosta, W. J. Glaccum, G. Helou, J. Karr, P. J. Lowrance, J. O'Linger, D. Padgett, R. Ramirez, L. M. Rebull, J. R. Stauffer, S. R. Stolovy, S. Wachter, BLANK BLANK, BLANK BLANK ()

We discovered new HII regions and a possible supernova remnant in infrared light from the Spitzer Galactic First Look Survey. We present observations towards G254.4+0.0 and G105.6+4 in seven bands of IRAC and MIPS data taken on Dec. 2003. First, a previously unidentified ultra compact HII region with ~2 arcmin size is detected at all IRAC and MIPS bands and is bright at 70um image. The high resolution Spitzer image now allows us to identify its infrared morphology as core-halo morphology, and the color contrast among the different wavelengths resolves temperature differences; hotter at the center and cooler in the envelope. We identified a corresponding CO clump in the Canadian CO survey with a velocity of -9 km s-1 and a distance of 1 kpc. Second, we found a few small HII regions around late O and/or early B stars with a few arcmin sizes, particularly bright at 24\mum, suggesting that the infrared emission is from directly heated dust grains. Third, a possible supernova remnant is identified; global morphology is shell-like but it has extremely clumpy structures both at the shell and interior. The emission is consistently bright at all wavelengths and no corresponding H\alpha emission is present. The shell structure is coinciding with faint radio emission in NVSS survey map. The morphology and infrared spectral energy distribution suggest it is a supernova remnant although other possibilities are an HII region or a nebula around luminous blue variable. Spitzer observations are opening a new era in the study of HII regions and supernova remnants with associated star forming activities.

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