Backreaction in relativistic
hydrodynamic accretion onto a spherical body
Dr hab. Edward Malec
We describe general-relativistically a stationary fluid accretion onto
central body. The obtained
formalism includes effects of backreaction and allows for the description
of thick and heavy clouds of gas surrounding a light nuclei. A numerical
example shows that even infall of
a light gas can induce a significant backreaction in a vicinity of
a supermassive black hole.
Backreaction can be neglected when the mass of a fluid is low in comparison
to the total mass and a local condition is satisfied. Accretion solutions
on a fixed spherical background possess at most one sonic
point. The speed of sound and a gas density monotonously decrease
and they are bounded. Predictions of a relativistic model and the Bondi
model strongly diverge for a 10^{10}K temperature gas.