2010/10/31 by C. B. Brook, F. Governato, R. Roskar +11 · 249 citations
Physics and Astronomy · #Angular momentum #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Cold dark matter #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Protogalaxy #Specific relative angular momentum #Supernova #astro-ph.CO
paper · pdf · doi:10.1111/j.1365-2966.2011.18545.x
published in Monthly Notices of the Royal Astronomical Society 415(2), 1051-1060 (Oxford University Press) · accepted version: MNRAS in press
arxiv created 2011/03/04 · openalex publication_date 2011/05/02 · arxiv updated 2015/05/20 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
Using high resolution, fully cosmological smoothed particle hydrodynamical simulations of dwarf galaxies in a Lambda cold dark matter Universe, we show how high redshift gas outflows can modify the baryon angular momentum distribution and allow pure disc galaxies to form. We outline how galactic outflows preferentially remove low angular momentum material due a combination of (a) star formation peaking at high redshift in shallow dark matter potentials, an epoch when accreted gas has relatively low angular momentum, (b) the existence of an extended reservoir of high angular momentum gas in the outer disc to provide material for prolonged SF at later times and (c) the tendency for outflows to follow the path of least resistance which is perpendicular to the disc. We also show that outflows are enhanced during mergers, thus expelling much of the gas which has lost its angular momentum during these events, and preventing the formation of ‘classical’, merger driven bulges in low-mass systems. Stars formed prior to such mergers form a diffuse, extended stellar halo component similar to those detected in nearby dwarfs.