TY - JOUR
T1 - Stellar winds pump the heart of the Milky Way
AU - Calderón, Diego
AU - Cuadra, Jorge
AU - Schartmann, Marc
AU - Burkert, Andreas
AU - Russell, Christopher M.P.
N1 - Funding Information:
We thank the anonymous referee for useful comments and suggestions that improved this article. D.C. and J.C. acknowledge the kind hospitality of the Max Planck Institute for Extraterrestrial Physics as well as funding from the Max Planck Society through a “Partner Group” grant. We thank F. E. Bauer and J. Dexter for useful discussions and suggestions for improving this work. The authors acknowledge support from CONICYT project Basal AFB-170002. D.C. is supported by CONICYT-PCHA/Doctorado Nacional (2015-21151574). C.M. P.R. is supported by FONDECYT grant 3170870. Numerical simulations were run on the high-performance computing system COBRA of the Max Planck Computing and Data Facility. Data analysis was carried out making use of the PYTHON package YT (Turk et al. 2011).
Publisher Copyright:
© 2019. The American Astronomical Society. All rights reserved.
PY - 2020/1/1
Y1 - 2020/1/1
N2 - The central supermassive black hole of the Milky Way, Sgr A*, accretes at a very low rate making it a very underluminous galactic nucleus. Despite the tens of Wolf–Rayet stars present within the inner parsec supplying ∼10−3 Me yr−1 in stellar winds, only a negligible fraction of this material (<10−4) ends up being accreted onto Sgr A*. The recent discovery of cold gas (∼104 K) in its vicinity raised questions about how such material could settle in the hostile (∼107 K) environment near Sgr A*. In this work we show that the system of mass-losing stars blowing winds can naturally account for both the hot, inefficient accretion flow, as well as the formation of a cold disk-like structure. We run hydrodynamical simulations using the grid-based code RAMSES starting as early in the past as possible to observe the state of the system at the present time. Our results show that the system reaches a quasi-steady state in about ∼500 yr with material being captured at a rate of ∼10−6 Me yr−1 at scales of ∼10−4 pc, consistent with the observations and previous models. However, on longer timescales (≿3000 yr) the material accumulates close to the black hole in the form of a disk. Considering the duration of the Wolf–Rayet phase (∼105 yr), we conclude that this scenario has likely already happened, and could be responsible for the more active past of Sgr A*, and/or its current outflow. We argue that the hypothesis of the mass-losing stars being the main regulator of the activity of the black hole deserves further consideration.
AB - The central supermassive black hole of the Milky Way, Sgr A*, accretes at a very low rate making it a very underluminous galactic nucleus. Despite the tens of Wolf–Rayet stars present within the inner parsec supplying ∼10−3 Me yr−1 in stellar winds, only a negligible fraction of this material (<10−4) ends up being accreted onto Sgr A*. The recent discovery of cold gas (∼104 K) in its vicinity raised questions about how such material could settle in the hostile (∼107 K) environment near Sgr A*. In this work we show that the system of mass-losing stars blowing winds can naturally account for both the hot, inefficient accretion flow, as well as the formation of a cold disk-like structure. We run hydrodynamical simulations using the grid-based code RAMSES starting as early in the past as possible to observe the state of the system at the present time. Our results show that the system reaches a quasi-steady state in about ∼500 yr with material being captured at a rate of ∼10−6 Me yr−1 at scales of ∼10−4 pc, consistent with the observations and previous models. However, on longer timescales (≿3000 yr) the material accumulates close to the black hole in the form of a disk. Considering the duration of the Wolf–Rayet phase (∼105 yr), we conclude that this scenario has likely already happened, and could be responsible for the more active past of Sgr A*, and/or its current outflow. We argue that the hypothesis of the mass-losing stars being the main regulator of the activity of the black hole deserves further consideration.
UR - http://www.scopus.com/inward/record.url?scp=85079735117&partnerID=8YFLogxK
U2 - 10.3847/2041-8213/ab5e81
DO - 10.3847/2041-8213/ab5e81
M3 - Article
AN - SCOPUS:85079735117
SN - 2041-8205
VL - 888
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
ER -