Cosmological self-similar shock waves and galaxy formation

Journal Article · Sun May 01 00:00:00 EDT 1983 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160925· OSTI ID:6048944

Bertschinger, E

A new family of similarity solutions is found for a point blast in a ..cap omega.. = 1 Friedmann cosmology (Einstein--de Sitter universe). The given solutions are valid several Hubble times after an explosion. Initially the shock wave formed satisfies the Sedov solution for adiabatic evolution in a constant medium, but it is modified by the cosmological expansion to form a self-similar thin dense shell which cools by adiabatic expansion and is unstable to gravitational fragmentation and collapse. The shock solution is applied to the explosive amplification model of galaxy formation of Ostriker and Cowie. It is shown that earlier than 1+zapprox.9, inverse Compton and free-free cooling prevent galactic-scale shocks from forming. At smaller redshifts, galactic shocks cool adiabatically to form cosmological dense-shelled shocks. Line cooling becomes important in the dense shells, cooling them to approx.10/sup 4/ K and setting the Jeans mass to galactic scales. One generation of explosive amplification from an initial ''seed'' galaxy produces a shell of approx.3 x 10/sup 11/ M/sub sun/ in galaxies, with radius and velocity dispersion typical of small groups. There may be time for a second generation (though no more); the resulting shell of approx.2 x 10/sup 13/ M/sub sun/ has radius and velocity dispersion characteristic of small clusters of galaxies.

• Research Organization: Princeton University Observatory
• OSTI ID: 6048944
• Journal Information: Astrophys. J.; (United States), Vol. 268:1
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMOLOGY
SHOCK WAVES
GALACTIC EVOLUTION
COSMOLOGICAL MODELS
ADIABATIC PROCESSES
EXPANSION
GALAXIES
GALAXY CLUSTERS
HYDRODYNAMICS
RELATIVITY THEORY
UNIVERSE
FIELD THEORIES
FLUID MECHANICS
GENERAL RELATIVITY THEORY
MATHEMATICAL MODELS
MECHANICS
640106* - Astrophysics & Cosmology- Cosmology
640105 - Astrophysics & Cosmology- Galaxies