Hyper-Eddington accretion flows on to massive black holes
By K. Inayoshi, Zoltán Haiman, Jeremiah P. Ostriker. 2015
169 citations recorded by the source corpus.
We study very-high rate spherically symmetric accretion flows onto a massive black hole (BH; 10 2 . MBH . 10 6 M⊙) embedded in a dense gas cloud with a low abundance of metals, performing one-dimensional hydrodynamical simulations which include multi-frequency radiation transfer and non-equilibrium primordial chemistry. We find that rapid gas supply from the Bondi radius at a hyper-Eddington rate can occur without being impeded by radiation feedback when (n∞/10 5 cm −3 ) > (MBH/10 4 M⊙) −1 (T∞/10 4 K) 3/2 , where n∞ and T∞ are the density and temperature of ambient gas outside of the Bondi radius. The resulting accretion rate in this regime is steady, and larger than 3000 times the Eddington rate. At lower Bondi rates, the accretion is episodic due to radiative feedback and the average rate is limited below the Eddington rate. For the hyper-Eddington case, the steady solution consists of two parts: a radiation-dominated central core, where photon trapping due to electron scattering is important, and an accreting envelope which follows a Bondi profile with T ≃ 8000 K. When the emergent luminosity is limited below the Eddington luminosity because of photon trapping, radiation from the central region does not affect the gas dynamics at larger scales. We apply our result to the rapid formation of massive BHs in protogalaxies with a virial temperature of Tvir & 10 4 K. Once a seed BH forms at the center of the galaxy, it can grow up to a maximum ∼ 10 5 (Tvir/10 4 K) M⊙ via gas accretion independent of the initial BH mass. Finally, we discuss possible observational signatures of rapidly accreting BHs with/without allowance for dust. We suggest that these systems could explain Lyα emitters without X-rays and luminous infrared sources with hot dust emission, respectively.
Subfields: Astronomy and Astrophysics, Mechanical Engineering
View Paper: https://www.semanticscholar.org/paper/78afdb4e6ee4ae82101c9e9a47cf28cc9d9a7c34
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Citations in the corpus
- Pōniuā‘ena: A Luminous z = 7.5 Quasar Hosting a 1.5 Billion Solar Mass Black Hole (2020, background): “It has been suggested that maintaining super-Eddington accretion might be possible in specific environments (Inayoshi et al. 2016; Smith et al. 2017), but whether or not this mode of rapid black hole growth is sustainable remains an important open question.”
- Unveiling the gravitational universe at μ-Hz frequencies (2019, background): “[38, 140, 175, 195, 275]), the emergence and eventual collapse of a supermassive star, formed as a result of unusually rapid accretion [127, 137, 211], an extremely massive black hole seed formed by relativistic “dark collapse” of a supermassive cloud bypassing the supermassive star stage [183], a m”
- Formation of Supermassive Black Hole Seeds (2016, background): “Depending on the IMF, Pop III BH binaries may produce distinct features in the gravitational wave background in 10- 100 Hz band and yield constraints on the abundance of Pop III BHs (Hartwig et al. 2016; Inayoshi et al. 2016; Ricotti 2016).”