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| Paper: |
ISM and OB Star Formation in Starbursts and AGN |
| Volume: |
249, The Central Kiloparsec of Starbursts and AGN: the La Palma Connection |
| Page: |
591 |
| Authors: |
Scoville, N. Z.; Polletta, M. |
| Abstract: |
Molecular gas in the central regions of galaxies plays a critical role in fueling nuclear starburst activity and feeding central AGN. The dense molecular ISM is concentrated by spiral density waves, or accreted to smaller galactic radii by stellar bars and galactic interactions. Here, we review results from our recent HST Hα and Pα imaging of H ii regions in M51 which are used to define the properties of ``normal'' OB star cluster formation. We find an upper limit to the mass of individual OB star clusters of a few thousand msun and suggest that this is due to accretion and star formation in a cloud core region being terminated at the point where radiation pressure on the surrounding dust exceeds the self-gravity of the core star cluster. In luminous infrared galaxies such as Arp 220, nuclear starbursts and active nuclei are fueled by extraordinarily large masses of gas and dust (>= 109 msun) concentrated at radii of a few hundred pc by galactic merging. In the extreme object Arp 220, high-resolution NICMOS and mm-wave interferometric imaging indicate double nuclei separated by ~350 pc, each of which is embedded in a massive gas and dust disk. Although the geometry in Arp 220 is clearly different than a spherical cloud core forming a single OB star cluster, the star formation may also be self-regulated at ~103 msun yr-1 by the radiation pressure arising from the starburst which can swell the disks vertically and self-regulate the star formation. |
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