Spherically Symmetric Accretion onto a Black Hole at the Center of a Young Stellar Cluster

Abstract

Here we present a self-consistent, bimodal stationary solution for spherically symmetric flows driven by young massive stellar clusters with a central supermassive black hole (SMBH ). We demonstrate that the hydrodynamic regime of the flow depends on the location of the cluster in the 3D (star cluster mechanical luminosityYBH massY star cluster radius) parameter space. We show that a threshold mechanical luminosity (L crit ) separates clusters that evolve in the BH-dominated regime from those whose internal structure is strongly affected by the radiative cooling. In the first case ( below the threshold energy) gravity of the BH separates the flow into two distinct zones: the inner accretion zone and the outer zone where the star cluster wind is formed. In the second case (above the critical luminosity), catastrophic cooling sets in inside the cluster. In this case the injected plasma becomes thermally unstable, which inhibits a complete stationary solution. We compared the calculated accretion rates and the BH luminosities with those predicted by the classic Bondi accretion theory and found that Bondi's theory is in good agreement with our results in the case of low-mass clusters. However, it substantially underestimates the accretion rates and BH luminosities if the star cluster mechanical luminosity L SC ! 0:1L crit .

Multiphase environment of compact galactic nuclei: the role of the nuclear star cluster

“…We study the above-mentioned type of TI, paying attention to the description of the heating/cooling processes of matter with the use of the photoionization code cloudy (Ferland 1996;Ferland et al 2013). A simple parametrization of the gas cooling rate from Plewa (1995) was employed by Silich et al (2008), while we add a more detailed description of the system. In particular, we include the spectral shape of the incident radiation from NSC.…”

Huffing, and puffing, and blowing your house in: Strong stellar winds interaction with a super massive black hole

“…The analytic models that we develop are similar to the ones of Silich et al (2008), who also modeled a wind from a cluster with a central SMBH. Our models differ from their results in that we include both the gravitational pull of the SMBH and the motions of the stars.…”

“…Our models differ from their results in that we include both the gravitational pull of the SMBH and the motions of the stars. These motions were not included in the analytic model of Silich et al (2008).…”

“…• Silich et al (2008) presented analytical considerations and numerical solutions of the steady state version of the same equations,…”

“…• Yalinevich et al (2018) studied the same problem as Silich et al (2008), and presented analytic solutions for different limiting regimes.…”