The problem of stationary, spherically symmetric accretion onto a Schwarzschild black hole is discussed here with the use of a formalism which is completely consistent with Einstein's General theory of Relativity. The transfer of heat is a significant part of this process, however treating it without approximations has proven difficult. Here I explore the adiabatic case first; then I consider a more general case by assuming that all the heat transfer happens through electromagnetic radiation. For the latter I apply the PSTF formalism which, roughly speaking, while still being relativistic allows for the decomposition of the radiation into its first moments: energy density and flux. The numerical analysis of the differential equations the problem can be reduced to shows a bimodal behaviour: a branch of solutions has a much higher efficiency (ratio of luminosity to accretion rate) than another. In order to treat this problem, first I briefly recall the formalism of general relativity; then I treat the basics of the relativistic formulation of the fluid dynamical equations, including the relativistic version of the Second Principle of thermodynamics.

### Relativistic Non-ideal flows

#### Abstract

The problem of stationary, spherically symmetric accretion onto a Schwarzschild black hole is discussed here with the use of a formalism which is completely consistent with Einstein's General theory of Relativity. The transfer of heat is a significant part of this process, however treating it without approximations has proven difficult. Here I explore the adiabatic case first; then I consider a more general case by assuming that all the heat transfer happens through electromagnetic radiation. For the latter I apply the PSTF formalism which, roughly speaking, while still being relativistic allows for the decomposition of the radiation into its first moments: energy density and flux. The numerical analysis of the differential equations the problem can be reduced to shows a bimodal behaviour: a branch of solutions has a much higher efficiency (ratio of luminosity to accretion rate) than another. In order to treat this problem, first I briefly recall the formalism of general relativity; then I treat the basics of the relativistic formulation of the fluid dynamical equations, including the relativistic version of the Second Principle of thermodynamics.
##### Scheda Scheda DC
2019-09-09
37
fluid dynamics, general relativity, black holes, accretion flows
File in questo prodotto:
File
Tissino_Jacopo.pdf

accesso aperto

Dimensione 549.32 kB
Utilizza questo identificativo per citare o creare un link a questo documento: `https://hdl.handle.net/20.500.12608/22272`