Gas Density, Stability, and Starbursts near the Inner Lindblad Resonance of the Milky Way
Abstract
A key project of the Antarctic Submillimeter Telescope and Remote Observatory reported by Martin et al. is the mapping of CO J=4-->3 and J=7-->6 emission from the inner Milky Way, allowing determination of gas density and temperature. Galactic center gas that Binney et al. identify as being on x2 orbits has a density near 103.5 cm-3, which renders it only marginally stable against gravitational coagulation into a few giant molecular clouds, as discussed by Elmegreen. This suggests a relaxation oscillator mechanism for starbursts in the Milky Way, whereby inflowing gas accumulates in a ring at 150 pc radius until the critical density is reached and the resulting instability leads to the sudden formation of giant clouds and the deposition of 4×107 Msolar of gas onto the Galactic center. Depending on the accretion rate near the inner Lindblad resonance, this cycle will repeat with a timescale of order 20 Myr.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2004
- DOI:
- 10.1086/425304
- arXiv:
- arXiv:astro-ph/0405330
- Bibcode:
- 2004ApJ...614L..41S
- Keywords:
-
- Galaxies: Starburst;
- Galaxy: Structure;
- ISM: Clouds;
- ISM: Molecules;
- Stars: Formation;
- Astrophysics
- E-Print:
- 11 pages, 1 table 1 color figure, submitted to ApJL