Bondi accretion in the finite luminous region of elliptical galaxies

Abstract

The classical Bondi model is adopted to study accretion onto the finite luminous region around the central massive black hole (MBH) in an elliptical galaxy. Unlike Bondi (1952), we define the boundary conditions at a certain finite radius (r f ) instead of at the infinity and examine the variation of solutions for a simple case. In the following, we consider the special case of a MBH at the center of a Hernquist galaxy and involve the gravity and luminosity of its own galaxy. Our results in the first part show that kinitic energy at the final radius is ignorable even for not so far away from the center. Moreover, the mass accretion rate will be approximately equal to its Bondi value if the final radius (r f ) becomes about 2-3 orders of magnitude larger than semi-Bondi radius, i.e. GM/c 2 sf (where M and c sf are the mass of the central object and the sound speed at r f ). In the second part, adding the two extra forces of gravity and radiation in the momentum equation let us know that the maximum possible of accretion rate increases with greater characteristic linear density of galaxy and lower radiation.

Outflows from inflows: the nature of Bondi-like accretion

“…Solutions to the classic Bondi problem depend only on γ and RB, whereas solutions with a boundary at finite Ro also depend on the value of Ro/RB. This dependence has been recently explored by Samadi et al (2019) and the solution procedure has been detailed by Waters & Proga (2012) in the context of Parker winds. Our initial conditions (ICs) are v θ = v φ = 0, while vr, ρ, and p are the semianalytic solutions to this generalized 1D Bondi problem under a BC ρ bdy (R0, θ) given below; the code for these ICs is publicly available at github.com/trwaters/bondiparker.…”

On the polytropic Bondi accretion in two-component galaxy models with a central massive BH

“…For future use, we now resume the framework used in the previous works (KCP16; CP17; CP18) to discuss the Bondi accretion onto MBHs at the centre of galaxies, also in presence of radiation pressure due to electron scattering (see e.g. Taam, Fu & Fryxell 1991;Fukue 2001;Lusso & Ciotti 2011;Raychaudhuri, Ghosh & Joarder 2018;Samadi, Zanganeh & Abbassi 2019;Ramírez-Velasquez et al 2019), and including the additional gravitational field of the galaxy. The radiation feedback, in the optically thin regime, can be implemented as a reduction of the gravitational force of the MBH by the factor…”

Global structure and dynamics of slowly rotating accretion flows

“…This could be one of the reasons most recent Bondi solutions are taking into account the galaxy's potential alongside the black hole's potential. (Mancino et al (2022), Samadi et al (2019), Ciotti & Pellegrini (2017)). Our numerical solutions with or without nuclear stars' gravity are summarized in Tables 1.…”

“…Also, BY19 studied the slowly rotating low accretion rate flow irradiated by an LLAGN in the presence of wind and the gravity of stars in the galaxy. Further, in recent years, the Bondi model has developed by considering the gravitational potential of the galaxy (Ciotti & Pellegrini (2018), Korol et al (2016), Samadi et al (2019), Quataert & Narayan (2000) due to the sizeable dynamical scale of the accretion process, from Bondi radius to the Schwarzschild radius of the black hole.…”