Strong shock in a uniformly expanding universe
Abstract
Propagation of the strong shock in the flat expanding Friedman universe is investigated using methods of dimension and similarity. Exact analytic solution of selfsimilar equations is obtained, determining dependences of the radius and velocity of the shock wave on time and radius. It is obtained, that in the expanding medium the velocity of shock decreases as $\sim t^{1/5}$, what is slower than the shock velocity in the static uniform medium $\sim t^{3/5}$. The radius of the shock wave in the expanding selfgravitating medium increases $\sim t^{4/5}$, more rapidly than the shock wave radius in the uniform nongravitating medium $\sim t^{2/5}$. So, the shock propagates in the direction of decreasing density with larger speed, that in the static medium, due to accelerating action of the decreasing density, even in the presence of a selfgravitation.
 Publication:

Gravitation and Cosmology
 Pub Date:
 July 2015
 DOI:
 10.1134/S0202289315030032
 arXiv:
 arXiv:1408.1918
 Bibcode:
 2015GrCo...21..236B
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 Mathematical Physics
 EPrint:
 16 pages. Shorter version is published in Gravitation and Cosmology, 2015, vol.21, pp. 236240