2004/09/27 by James Binney, Binney, James
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0409639
8 pages to appear in "Extraplanar Gas", ed. R. Braun, ASP Conf. Procs
arxiv created 2004/09/27 · arxiv updated 2009/12/01
I review evidence that galaxies form from gas that falls into potential wells cold, rather than from virialized gas, and that formation stops once an atmosphere of trapped virialized gas has accumulated. Disk galaxies do not have such atmospheres, so their formation is ongoing. During galaxy formation feedback is an efficient process, and the nuclear regions of disk galaxies blow winds. The cold infalling gas that drives continued star formation has a significant component of angular momentum perpendicular to that of the disk. Extraplanar gas has to be understood in the context set by nuclear outflows and cold skew-rotating cosmic infall.