Hoyle–Lyttleton accretion on to black hole accretion disks with super-Eddington luminosity for dusty gas

Abstract

We investigate the Hoyle–Lyttleton accretion of dusty gas for the case where the central source is the black hole accretion disk. By solving the equation of motion taking into account the radiation force which is attenuated by the dust absorption, we reveal the steady structure of the flow around the central object. We find that the mass accretion rate tends to increase with an increase of the optical thickness of the flow and the gas can accrete even if the disk luminosity exceeds the Eddington luminosity for the dusty gas, since the radiation force is weakened by the attenuation via the dust absorption. When the gas flows in from the direction of the rotation axis for the disk with Γ′ = 3.0, the accretion rate is about $93\%$ of the Hoyle–Lyttleton accretion rate if τHL = 3.3 and zero for τHL = 1.0, where Γ′ is the Eddington ratio for the dusty gas and τHL is the typical optical thickness of the Hoyle–Lyttleton radius. Since the radiation flux in the direction of disk plane is small, the radiation force tends not to prevent gas accretion from the direction near the disk plane. For τHL = 3.3 and Γ′ = 3.4, although the accretion is impossible in the case of Θ = 0°, the accretion rate is $28\%$ of the Hoyle–Lyttleton one in the case of Θ = 90°, where Θ is the angle between the direction the gas is coming from and the rotation axis of the disk. We also obtain relatively high accretion luminosity that is realized when the accretion rate of the disk on to the BH is consistent with that via the Hoyle–Lyttleton mechanism taking into account the effect of radiation. This implies that the intermediate-mass black holes moving in the dense dusty gas are identified as luminous objects in the infrared band.

An Origin of Narrow Extended Structure in the Interstellar Medium: An Interstellar Contrail Created by a Fast-moving Massive Object

“…Accretion onto a moving gravitating source is called Bondi-Hoyle-Littleton accretion (Hoyle & Lyttleton 1939, 1941Bondi & Hoyle 1944), and the mass accretion rate to the gravitating source can be estimated by p r = This value seems to be too small to be observed. A detailed discussion on observability is beyond the scope of this paper (see, e.g., Fukue & Ioroi 1999;Ogata et al 2021).…”

An origin of narrow extended structure in the interstellar medium: an interstellar contrail created by a fast-moving massive object

“…This value seems to be too small to be observed. A detailed discussion on observability is beyond the scope of this paper (see, e.g., Fukue & Ioroi 1999;Ogata et al 2021).…”

Gas Dynamical Friction on Accreting Objects

“…Gas accretion onto moving objects has been studied through analytic consideration (e.g., Hoyle & Lyttleton 1939;Bondi & Hoyle 1944) and hydrodynamic simulations (e.g., Hunt 1971Hunt , 1979Shima et al 1985;Ruffert 1994aRuffert , 1994bRuffert & Arnett 1994;Ruffert 1995Ruffert , 1996Edgar 2004 for a review) for the case of uniform linear motion in a homogeneous medium. The case in which the central object is a BH and exerts radiative feedback on the surrounding gas has also been studied through radiative hydrodynamic simulations (e.g., Park & Ricotti 2013;Park & Bogdanović 2017;Sugimura & Ricotti 2020;Toyouchi et al 2020;Ogata et al 2021Ogata et al , 2024. However, the focus of the above studies is mainly on mass accretion growth rather than the gas dynamical friction.…”