Energy flows in thick accretion discs and their consequences for black hole feedback

• We study energy flows in geometrically thick accretion discs, both optically thick and thin, using general relativistic, three-dimensional simulations of black hole accretion flows. We find that for non-rotating black holes the efficiency of the total feedback from thick accretion discs is 3 per cent - roughly half of the thin disc efficiency. This amount of energy is ultimately distributed between outflow and radiation, the latter scaling weakly with the accretion rate for super-critical accretion rates, and returned to the interstellar medium. Accretion on to rotating black holes is more efficient because of the additional extraction of rotational energy. However, the jet component is collimated and likely to interact only weakly with the environment, whereas the outflow and radiation components cover a wide solid angle.

Subject headings

NATURVETENSKAP  -- Fysik -- Astronomi, astrofysik och kosmologi (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Astronomy, Astrophysics and Cosmology (hsv//eng)

Keyword

accretion

accretion discs

black hole physics

relativistic processes

methods: numerical

ADVECTION-DOMINATED ACCRETION

X-RAY BINARIES

MAGNETIC-FLUX

RELATIVISTIC MAGNETOHYDRODYNAMICS

ELECTROMAGNETIC EXTRACTION

DIFFUSION-COEFFICIENTS

NUMERICAL-SIMULATION

GENERAL-RELATIVITY

VERTICAL STRUCTURE

DISKS

Publication and Content Type

ref (subject category)

art (subject category)