BASS. LIII. The Eddington Ratio as the Primary Regulator of the Fraction of X-Ray Emission in Active Galactic Nuclei
Year: 2025
Type: article
Abstract: Active galactic nuclei (AGN) emit radiation via accretion across the entire energy spectrum. While the standard disk and corona model can somewhat describe this emission, it fails to predict specific features such as the soft X-ray excess, the short-term optical/UV variability, and the observed UV/X-ray correlation in AGN. In this context, the fraction of AGN emission in different bands (i.e., bolometric corrections) can be useful to better understand the accretion physics of AGN. Past studies have shown that the X-ray bolometric corrections are strongly dependent on the physical properties of AGN, such as their luminosities and Eddington ratios. However, since these two parameters depend on each other, it has been unclear which is the main driver of the X-ray bolometric corrections. We present here results from a large study of hard-X-ray-selected (14–195 keV) nearby (z < 0.1) AGN. Based on our systematic analysis of the simultaneous optical-to-X-ray spectral energy distributions of 236 unobscured AGN, we found that the primary parameter controlling the X-ray bolometric corrections is the Eddington ratio. Our results show that, while the X-ray bolometric correction increases with the bolometric luminosity for sources with intermediate Eddington ratios (0.01–1), this dependence vanishes for sources with lower Eddington ratios (<0.01). This could be used as evidence for a change in the accretion physics of AGN at low Eddington ratios.
Source: The Astrophysical Journal
Authors: Kriti Kamal Gupta, Claudio Ricci, Alessia Tortosa, Matthew J. Temple, Michael J. Koss, Benny Trakhtenbrot, Franz E. Bauer, Ezequiel Treister, Richard Mushotzky, Elias Kammoun, Iossif Papadakis, Kyuseok Oh, Alejandra Rojas, Chin-Shin Chang, Yaherlyn Diaz, Arghajit Jana, Darshan Kakkad, Ignacio del Moral-Castro, Alessandro Peca, Meredith C. Powell, Daniel Stern, C. Megan Urry, Fiona Harrison
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: Smithsonian Institution, National Aeronautics and Space Administration, California Institute of Technology, European Space Agency, European Commission, National Research Foundation, Deutsche Forschungsgemeinschaft, Belgian Federal Science Policy Office, Korea Astronomy and Space Science Institute, National Research Foundation of Korea, Pontificia Universidad Católica de Chile, Ministry of Science and ICT, South Korea, Agencia Nacional de Investigación y Desarrollo, Jet Propulsion Laboratory, Goddard Space Flight Center, Smithsonian Astrophysical Observatory, Science and Technology Facilities Council, Astrophysics Science Division, Astrophysics Division
Awards: INSTITUTO MILENIO DE ASTROFISICA, EXTREME SUPERMASSIVE BLACK HOLE ACCRETION, G1897041155, G2329447088, G2428672771, G2619569784, UNVEILING THE PHYSICAL PROPERTIES OF THE CIRCUMNUCLEAR ENVIRONMENT IN ACTIVE GALACTIC NUCLEI, G272317890, G2810258421, THE NUCLEI OF THE MOST ACTIVE GALAXIES IN THE LOCAL UNIVERSE AT THE HIGHEST RESOLUTIONS, G4066435496, AN UNPRECEDENTED CENSUS OF BLACK HOLE ACTIVITY IN THE LSST ERA, A SYSTEMATIC STUDY OF CHANGING-LOOK AGN IN THE LOCAL UNIVERSE, EXC 2094: ORIGINS: Vom Ursprung des Universums bis zu den ersten Bausteinen des Lebens, A COMPREHENSIVE VIEW OF THE CONNECTION BETWEEN SUPERMASSIVE BLACK HOLE GROWTH AND MAJOR GALAXY MERGERS, G4798287788, EXTREME SPECTRAL VARIABILITY IN ACTIVE GALACTIC NUCLEI - PAVING THE WAY FOR LSST, SPECTRO-TEMPORAL STUDIES OF AGN POPULATIONS, CENTRO DE ASTROFISICA Y TECNOLOGIAS AFINES (CATA)
OpenAlex ID: W4413803435