Radiative Shocks in Rotating Accretion Flows around Black Holes

Abstract

It is well known that the rotating inviscid accretion flows with adequate injection parameters around black holes could form shock waves close to the black holes, after the flow passes through the outer sonic point and can be virtually stopped by the centrifugal force. We examine numerically such shock waves in 1D and 2D accretion flows, taking account of cooling and heating of the gas and radiation transport. The numerical results show that the shock location shifts outward compared with that in the adiabatic solutions and that the more rarefied ambient density leads to the more outward shock location. In the 2D-flow, we find an intermediate frequency QPO behavior of the shock location as is observed in the black hole candidate GRS 1915+105.

QPOs expected in rotating accretion flows around a supermassive black hole

“…The basic equations and the numerical methods used here are given in Okuda et al(2004). A typical set of injection parameters, such as the specific angular momentum, λ out , the radial velocity v out , the sound velocity a out , the ambient density ρ out , and the accretion rateṁ normalized to the Eddington critical accretion rateṀ E (= 2.7 × 10 23 g s −1 ) at an outer boundary radius R out , are given in table 1.…”

“…Here, following the recent numerical 2D simulations of the shocks (Okuda et al 2004.;Chakrabarti et al 2004. ), we examine the QPOs phenomena due to the centrifugally supported shocks around a supermassive black hole with 10 6 M , while taking account of the cooling and heating of the gas and the radiation transport.…”

Radiative 2D Shocks, Super-Eddington Disks and Jets around Black Holes

“…The basic equations and the numerical methods are given in [3] and [4], where the heating and cooling of gas and radiation transport are taken account of.…”

Soft X-Ray Excess From Shocked Accreting Plasma in Active Galactic Nuclei

“…Previous studies include hydrodynamic shocks (e.g., Nobuta & Hanawa 1994;Lu et al 1997;Chakrabarti 1990;Fukumura & Tsuruta 2004) and magnetohydrodynamic (MHD) shocks (e.g., Koide et al 1998Koide et al , 2000Das & Chakrabarti 2007;Takahashi et al 2002Takahashi et al , 2006Fukumura & Kazanas 2007b;Fukumura et al 2007, hereafter F07;Takahashi & Takahashi 2010). In particular, extensive theoretical studies of various types of shocks have been conducted to date in an attempt to understand their dynamical behavior; e.g., shock oscillation in the context of quasi-periodic oscillations and its spectroscopic signatures (e.g., Chakrabarti & Titarchuk 1995;Molteni et al 1996Molteni et al , 1999Acharya et al 2002;Okuda et al 2004Okuda et al , 2007Nagakura & Yamada 2008) that may be relevant for X-ray Binaries (XRBs), for example. Independent general relativistic (GR) MHD (GRMHD) simulations of the tilted accretion disk clearly show that the compression of the plunging plasma in the inner region (  r r 10 g ) leads to the formation of standing shocks (e.g., Fragile et al 2007;Fragile & Blaes 2008;Generozov et al 2014) depending on the characteristics of the disk geometry and the BH spin (e.g., Morales et al 2014).…”