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Precombination Cloud Collapse and Baryonic Dark MatterA simple spherical model of dense baryon clouds in the hot big bang 'strongly nonlinear primordial isocurvature baryon fluctuations' is reviewed and used to describe the dependence of cloud behavior on the model parameters, baryon mass, and initial over-density. Gravitational collapse of clouds before and during recombination is considered including radiation diffusion and trapping, remnant type and mass, and effects on linear large-scale fluctuation modes. Sufficiently dense clouds collapse early into black holes with a minimum mass of approx. 1 solar mass, which behave dynamically like collisionless cold dark matter. Clouds below a critical over-density, however, delay collapse until recombination, remaining until then dynamically coupled to the radiation like ordinary diffuse baryons, and possibly producing remnants of other kinds and lower mass. The mean density in either type of baryonic remnant is unconstrained by observed element abundances. However, mixed or unmixed spatial variations in abundance may survive in the diffuse baryon and produce observable departures from standard predictions.
Document ID
19970032262
Document Type
Reprint (Version printed in journal)
Authors
Hogan, Craig J.
(Washington Univ. Seattle, WA United States)
Date Acquired
August 17, 2013
Publication Date
October 1, 1993
Publication Information
Publication: The Astrophysical Journal
Issue: 415
Subject Category
Astrophysics
Report/Patent Number
NASA-CR-204215
NAS 1.26:204215
Funding Number(s)
CONTRACT_GRANT: NAGw-2569
CONTRACT_GRANT: NAGw-2523
Distribution Limits
Public
Copyright
Public Use Permitted.
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