Open AccessSelf‐similar cosmological expansion of collisional gas
Author(s) -
Chuzhoy Leonid,
Nusser Adi
Publication year - 2002
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.1365-8711.2002.05632.x
Subject(s) - physics , baryon , redshift , radius , compton scattering , astrophysics , universe , inverse , metric expansion of space , dark matter , circular symmetry , cosmology , dark energy , scattering , classical mechanics , quantum mechanics , geometry , computer security , mathematics , galaxy , computer science
We derive similarity solutions for the expansion of negative initial density perturbations δ M / M ∝ r − s ( s > 0) in an Einstein–de Sitter universe filled with collisional baryonic gas and collisionless matter. The solutions are obtained for planar, cylindrical and spherical perturbations. For steep perturbations, central cavities surrounded by overdense shells expanding as t 2( s + 1)/(3 s ) develop in both matter components. We also consider the case when baryonic shells are driven by internal pressure. Before redshift ∼8–10, baryonic shells cool by inverse Compton scattering with the cosmic background radiation and can form bound objects of mass ∼10 11 Ω b −1/2 M ⊙ (1+ z ) −3/2 . Hot shocks of radius R cause a Compton y ‐distortion of order y = 10 −5 Ω b ( R /10 Mpc) 2 f F , where f F is the volume filling factor of these shells.