Black hole accretion discs and jets at super-Eddington luminosity

Abstract

Super-Eddington accretion discs with 3M ̇ E and 15M ̇ E around black holes with mass 10 M⊙ are examined by two-dimensional radiation hydrodynamical calculations extending from the inner disc edge to 5 × 104rg and lasting up to ∼106 rg/c. The dominant radiation pressure force in the inner region of the disc accelerates the gas vertically to the disc plane, and jets with 0.2–0.4c are formed along the rotational axis. In the case of the lower accretion rate, the initially anisotropic high-velocity jet expands outward and becomes gradually isotropic flow in the distant region. The mass-outflow rate from the outer boundary is as large as ∼1019 –1023 g s−1, but it is variable and intermittent with time; that is, the outflow switches occa- sionally to inflow in the distant region. The luminosity also varies as ∼1040–1042 erg s−1 on a long time-scale. On the other hand, the jet in the case of the higher accretion rate maintains its initial anisotropic shape even after it goes far away. The mass-outflow rate and the luminosity attain steady values of 3 × 1019 g s−1 and 1.3 × 1040 erg s−1, respectively. In accordance with the local analysis of the slim accretion disc model, the disc is thermally unstable in the case of 3M ̇ E but stable in the case of 15M ̇ E. The super-Eddington model with 15M ̇ E promises to explain the small collimation degree of the jet and the large mass-outflow rate observed in the X-ray source SS 433

The General Relativistic Equations of Radiation Hydrodynamics in the Viscous Limit

“…Owing to their apparent complexity, the equations of radiation hydrodynamics, when applied to supercritically accreting compact objects and their surroundings, are often solved numerically (Eggum et al 1988;Okuda 2002;Okuda et al 2005;Ohsuga et al 2005;Ohsuga 2007). Simulations of such systems have also been extended to include magnetic fields (radiation magnetohydrodynamic; RMHD), the presence of which is potentially important not only for the dynamics of the gas but also for MRI-induced accretion and jet collimation (Turner et al 2003;Ohsuga et al 2009;Sądowski et al 2014;McKinney et al 2014).…”

Diagnostics of SS433 with the RXTE

“…Both simple estimates and more detailed calculations show that this geometrically thick accretion disk should have a height comparable to its radius H/R ∼ 1 (e.g. Okuda et al 2005;Nazarenko & Glazunova 2005).…”

SS433 as ultraluminous UV source. Comparison with ULXs

“…This means that the observed radiation of SS 433 was thermalized in a strong wind from the supercritical disc. The wind from a supercritical disc was first predicted by Shakura & Sunyaev ( [37]) and confirmed in radiation-hydrodynamic simulations ( [12,32,31]). These ideas have led the prediction that SS 433 being observed face-on appeares as an extremely bright X-ray source and we may expect a new type of X-ray sources in external galaxies ( [21,16,17]).…”