Mid-IR spectroscopy of hot and dusty, luminous high-z star forming galaxies
Abstract
We have identified a population of high-redshift microJy radio sources which have rest-UV/optical spectra characteristic of dusty luminous starbursts, and whose radio emission implies ~1000M/yr star formation rates, but which have no detectable submm emission from cool dust. These galaxies have S(24um)=0.1-1mJy similar to submm galaxies, and typically have enormous molecular gas reservoirs (confirmed through CO3-2 detections). Resolved radio morphologies with 3kpc scale sizes completes the picture: we propose that these 'optically faint radio galaxies' (OFRGs) are a new class of luminous dusty starburst with hotter dust temperatures than the similarly high-redshift ultraluminous submm galaxies. We propose Spitzer-IRS to observe the 10 confirmed star-forming OFRGs in our accepted molecular gas CO(3-2) study at the IRAM Plateau-de-Bure interferometer. We will probe the intense mid-IR emission from these galaxies for signatures of their power source, and to understand whether the aromatic features are sensitive to the more intense ionization fields in OFRGs compared with SMGs.
- Publication:
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Spitzer Proposal
- Pub Date:
- March 2008
- Bibcode:
- 2008sptz.prop50305C