Self-similar evolution of holes in an Einstein--de Sitter universe

Journal Article · Wed May 01 04:00:00 EDT 1985 · Astrophys. J., Suppl. Ser.; (United States)

DOI:https://doi.org/10.1086/191027· OSTI ID:5739639

Bertschinger, E

Similarity solutions have been found for the nonlinear evolution of isolated, spherical, negative density perturbations in an Einstein--de Sitter (..cap omega.. = 1) universe. A negative perturbation grows until it becomes a hole, which expands in a self-similar fashion, in most cases sweeping up and compressing the matter around it into a thin, dense shell. If there is no net mass deficit in the initial perturbation (i.e., the negative density perturbation is surrounded by a compensating overdense shell), the shell mass grows as t/sup 2/5/. A solution given previously for cosmological explosions then applies for a collisional (e.g., baryon) gas. New solutions are given here for a collisionless (e.g., massive neutrino or cold dark matter) gas and for the flow of an ..cap omega..<<1 collisional gas in the gravitational potential of the ..cap omega.. = 1 collisionless solution. If there is a finite net mass deficit in the initial density perturbation, a shell forms and grows in mass as t/sup 2/3/. New similarity solutions have been found in this case for collisionless, collisional, and mixed gases. In all these solutions, shell-crossing and caustics occur in the collisionless component, while shocks form in the collisional fluid. If the Local Supercluster is part of a shell around a giant hole, then the observed Hubble constant is too large for the universe as a whole by 33% if the hole is uncompensated, or 20% if it is compensated. It is argued that ''typical'' (rms) perturbations in a hierarchical clustering model cannot produce large distinct holes, so that if they are common, some source of higher-amplitude perturbations (e.g., adiabatic perturbations in a collisionless dark component, or explosions) may be necessary to produce such holes.

• Research Organization: Princeton University Observatory; and Department of Astronomy, University of Virginia
• OSTI ID: 5739639
• Journal Information: Astrophys. J., Suppl. Ser.; (United States), Journal Name: Astrophys. J., Suppl. Ser.; (United States) Vol. 58:1; ISSN APJSA
• Country of Publication: United States
• Language: English

Related Subjects

640106* -- Astrophysics &amp; Cosmology-- Cosmology
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMOLOGICAL MODELS
COSMOLOGY
DIAGRAMS
DISPERSION RELATIONS
DISTRIBUTION
DISTURBANCES
FLUID MECHANICS
HYDRODYNAMICS
MASS DISTRIBUTION
MATHEMATICAL MODELS
MECHANICS
NONLINEAR PROBLEMS
SHELLS
SHOCK WAVES
SPATIAL DISTRIBUTION
SYMMETRY
TABLES
UNIVERSE
VELOCITY
VOIDS