Open AccessThe formation of galaxy discs
Author(s) -
Silk Joseph
Publication year - 2001
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2001.04197.x
Subject(s) - physics , astrophysics , star formation , angular momentum , halo , galaxy , interstellar medium , supernova , galaxy formation and evolution , gravitational collapse , drag , dark matter halo , dark matter , astronomy , mechanics , classical mechanics
Galaxy disc formation must incorporate the multiphase nature of the interstellar medium. The resulting two‐phase structure is generated and maintained by gravitational instability and supernova energy input, which yield a source of turbulent viscosity that is able to compete effectively in the protodisc phase with early angular momentum loss of the baryonic component via dynamical friction in the dark halo. Provided that star formation occurs on the viscous drag time‐scale, this mechanism provides a means of accounting for disc sizes and radial profiles. The star formation feedback is self‐regulated by turbulent gas pressure limited percolation of the supernova remnant heated hot phase, but can run away in gas‐rich protodiscs to generate compact starbursts. A simple analytic model is derived for a Schmidt‐like global star formation law in terms of the cold gas volume density.