2008/02/04 by Filippo Fraternali, James Binney · 7 citations
Physics and Astronomy · #Accretion (finance) #Active galactic nucleus #Angular momentum #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Physics #Spiral galaxy #Star formation #Supernova #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.13071.x
11 pages, 6 figures, accepted for publication in MNRAS
arxiv created 2008/02/04 · openalex publication_date 2008/04/24 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We present evidence for cosmological gas accretion on to spiral galaxies in the local universe. The accretion is seen through its effects on the dynamics of the extraplanar neutral gas. The accretion rates that we estimate for two nearby spiral galaxies are of the order of their star formation rates. Our model shows that most of the extraplanar gas is produced by supernova feedback (galactic fountain) and only 10–20 per cent comes from accretion. The accreting material must have low specific angular momentum about the disc's spin axis, although the magnitude of the specific angular momentum vector can be higher. We also explore the effects of a hot corona on the dynamics of the extraplanar gas and find that it is unlikely to be responsible for the observed kinematical pattern and the source of accreted gas. However, the interaction with the fountain flow should profoundly affect the hydrodynamics of the corona.