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Gravitational instability in a primordial collapsing gas cloud

Lacey, Cedric G.

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This paper presents an analysis of the linear evolution of short-wavelength perturbations in a background fluid flow which is undergoing gravitational collapse on large scales. Local evolution equations for perturbations to an arbitrary flow are derived in the linear regime and the short-wavelength limit. Local perturbation behavior in an inhomogeneous flow is found to be the same as that in a homogeneous anisotropic flow having the same local velocity field. Background flows in which the scale factors vary as power laws in time are considered to illustrate the relative effects of self-gravity, pressure and kinematics of the background flow on the density perturbation evolution. Perturbation analyses are then presented for more realistic background flows arising from the evolution into the nonlinear regime of initially small density perturbations in an isotropically expanding cosmological model. For low-pressure, inhomogeneous collapses, kinematic effects tend to dominate over self-gravity in driving perturbation growth as the collapse proceeds.


Lacey, C. G. (1989). Gravitational instability in a primordial collapsing gas cloud. Astrophysical Journal, 336, 612-638.

Journal Article Type Article
Publication Date Jan 15, 1989
Deposit Date May 22, 2015
Publicly Available Date May 22, 2015
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 336
Pages 612-638
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Published Journal Article (484 Kb)

Copyright Statement
© 1989. The American Astronomical Society. All rights reserved. Printed in the U.S.A.

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