Structure of the super-Eddington outflow and itsimpact on the cosmological scale

2022/01/07 by Ignacio Botella, Shin Mineshige, Takaaki Kitaki +2
Physics and Astronomy · #Accretion (finance) #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Eddington luminosity #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Meteorology #Outflow #Physics #RADIUS #Redshift #Schwarzschild radius #Supermassive black hole #astro-ph.GA

paper · pdf · doi:10.1093/pasj/psac001

14 pages, 10 figures, published online in the Publications of the Astronomical Society of Japan

openalex publication_date 2022/01/07 · arxiv created 2022/02/28 · arxiv updated 2022/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06

Abstract

It is one of the biggest issues in black hole (BH) astrophysics how to precisely evaluate BH feedback to its environments. Aiming at studying the unique gas dynamics of super-Eddington flow around supermassive black hole (SMBH) seeds at high redshift, we carried out axisymmetric two dimensional radiation hydrodynamic simulations by a nested simulation-box method. Here we divide the simulation box into the inner zone at (2 - 3 × 10³) r_\rmSch (with r_{\rm Sch} being the Schwarzschild radius) and the outer zone at (2× 10³ - 3× 10⁶) r_\rmSch, with smooth connection of the physical quantities, such as gas density, velocity, and radiation energy. We start the calculation by injecting mass through the outer boundary of the inner zone at a constant rate of M_\rminj=10³L_\rmEdd/c², where L_\rmEdd is the Eddington luminosity and c is the speed of light. A powerful outflow is generated in the innermost region and it propagates from the inner zone to the outer zone. The outflows are characterized by a velocity of 0.02c (0.7c) and density of 10^-17 (10^-19) g cm^-3 for near the edge-on (face-on) direction. The outflow is gradually accelerated as it travels by accepting radiation-pressure force. The final mass outflow rate at the outermost boundary is M_\rmout∼ 0.3 × M_\rminj. By extrapolating the outflow structure to a further larger scale, we find that the momentum and energy fluxes at r ∼ 0.1 pc are ∼ 10-100 L_\rmEdd/c and ∼ 0.1-10 L_\rmEdd, respectively. Moreover, we find that the impacts are highly anisotropic in the sense that larger impacts are given towards the face-on direction than in the edge-on direction. These results indicate that the BH feedback will more efficiently work on the interstellar medium than that assumed in the cosmological simulations.

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