First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
Abstract
Abstract In this paper we provide a first physical interpretation for the Event Horizon Telescope's (EHT) 2017 observations of Sgr A*. Our main approach is to compare resolved EHT data at 230 GHz and unresolved non-EHT observations from radio to X-ray wavelengths to predictions from a library of models based on time-dependent general relativistic magnetohydrodynamics simulations, including aligned, tilted, and stellar-wind-fed simulations; radiative transfer is performed assuming both thermal and nonthermal electron distribution functions. We test the models against 11 constraints drawn from EHT 230 GHz data and observations at 86 GHz, 2.2 μ m, and in the X-ray. All models fail at least one constraint. Light-curve variability provides a particularly severe constraint, failing nearly all strongly magnetized (magnetically arrested disk (MAD)) models and a large fraction of weakly magnetized models. A number of models fail only the variability constraints. We identify a promising cluster of these models, which are MAD and have inclination i ≤ 30°. They have accretion rate (5.2–9.5) × 10 −9 M ⊙ yr −1 , bolometric luminosity (6.8–9.2) × 10 35 erg s −1 , and outflow power (1.3–4.8) × 10 38 erg s −1 . We also find that all models with i ≥ 70° fail at least two constraints, as do all models with equal ion and electron temperature; exploratory, nonthermal model sets tend to have higher 2.2 μ m flux density; and the population of cold electrons is limited by X-ray constraints due to the risk of bremsstrahlung overproduction. Finally, we discuss physical and numerical limitations of the models, highlighting the possible importance of kinetic effects and duration of the simulations.
Funding
- National Science Foundation
- Smithsonian Institution
- U.S. Department of Energy
- National Aeronautics and Space Administration
- Simons Foundation
- John Templeton Foundation
- Gordon and Betty Moore Foundation
- University of Chicago
- University of Arizona
- National Center for Theoretical Sciences
- Compute Canada
- Netherlands eScience Center
- Space Telescope Science Institute
- Ministerio de Ciencia, Innovación y Universidades
- National Radio Astronomy Observatory
- Associated Universities
- International Max Planck Research School for Environmental, Cellular and Molecular Microbiology
- Joint Institute for Computational Fundamental Science
- Flatiron Health
- Government of Canada
- Leverhulme Trust
- European Commission
- National Research Foundation
- University of Pretoria
- Deutsche Forschungsgemeinschaft
- Ministry of Education, Culture, Sports, Science and Technology
- Universiteit Leiden
- National Natural Science Foundation of China
- Universiteit van Amsterdam
- Radboud Universiteit
- Academia Sinica
- Academy of Finland
- Chinese Academy of Sciences
- China Postdoctoral Science Foundation
- Consejo Nacional de Ciencia y Tecnología
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek
- Generalitat Valenciana
- Nuclear Safety and Security Commission
- Korea Astronomy and Space Science Institute
- National Research Foundation of Korea
- Max-Planck-Gesellschaft
- Vetenskapsrådet
- Ministry of Education, India
- China Scholarship Council
- European Southern Observatory
- Centre National de la Recherche Scientifique
- Ministerio de Ciencia e Innovación
- Shanghai Jiao Tong University
- Universidad Nacional Autónoma de México
- National Astronomical Observatory of Japan
- Recruitment Program of Global Experts
- Junta de Andalucía
- Istituto Nazionale di Fisica Nucleare
- Ministry of Science and ICT, South Korea
- Instituto de Astrofísica de Andalucía
- Agencia Nacional de Investigación y Desarrollo
- Institut Périmètre de physique théorique
- East Asian Core Observatories Association
- Toray Science Foundation
- Office of Science
- National Nuclear Security Administration
- Physics Division, National Center for Theoretical Sciences
- Natural Sciences and Engineering Research Council of Canada
- Science and Technology Facilities Council
- Japan Society for the Promotion of Science
- Consejo Superior de Investigaciones Científicas
- Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México
- National Institutes of Natural Sciences
- National Key Research and Development Program of China
- Office of International Science and Engineering
- Astrophysics Division
- Oak Ridge National Laboratory
- Los Alamos National Laboratory
How this paper connects to the literature. Drag to explore, click any node to open that paper.
