Super-Eddington Accretion in Quasars

Fuente: arXiv
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Hauptverfasser: Marziani, P., Luna, K. Garnica, Floris, A., del Olmo, A., Deconto-Machado, A., Buendia-Rios, T. M., Negrete, C. A., Dultzin, D.
Format: Preprint
Veröffentlicht: 2025
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author Marziani, P.
Luna, K. Garnica
Floris, A.
del Olmo, A.
Deconto-Machado, A.
Buendia-Rios, T. M.
Negrete, C. A.
Dultzin, D.
author_facet Marziani, P.
Luna, K. Garnica
Floris, A.
del Olmo, A.
Deconto-Machado, A.
Buendia-Rios, T. M.
Negrete, C. A.
Dultzin, D.
contents This review provides an observational perspective on the fundamental properties of super-Eddington accretion onto supermassive black holes in quasars. It begins by outlining the selection criteria, particularly focusing on optical and UV broad-line intensity ratios, used to identify a population of unobscured super-Eddington candidates. Several defining features place these candidates at the extreme end of the Population A in main sequence of quasars: among them are the highest observed singly-ionized iron emission, extreme outflow velocities in UV resonance lines, and unusually high metal abundances. These key properties reflect the coexistence of a virialized sub-system within the broad-line region alongside powerful outflows, with the observed gas enrichment likely driven by nuclear or circumnuclear star formation. The most compelling evidence for the occurrence of super-Eddington accretion onto supermassive black holes comes from recent observations of massive black holes at early cosmic epochs. These black holes require rapid growth rates that are only achievable through radiatively inefficient super-Eddington accretion. Furthermore, extreme Eddington ratios, close to or slightly exceeding unity, are consistent with the saturation of radiative output per unit mass predicted by accretion disk theory for super-Eddington accretion rates. The extreme properties of super-Eddington candidates suggest that these quasars could make them stable and well-defined cosmological distance indicators, leveraging the correlation between broad-line width and luminosity expected in virialized systems. Finally, several analogies with accretion processes around stellar-mass black holes, particularly in the high/soft state, are explored to provide additional insight into the mechanisms driving super-Eddington accretion.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14713
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Super-Eddington Accretion in Quasars
Marziani, P.
Luna, K. Garnica
Floris, A.
del Olmo, A.
Deconto-Machado, A.
Buendia-Rios, T. M.
Negrete, C. A.
Dultzin, D.
Astrophysics of Galaxies
High Energy Astrophysical Phenomena
This review provides an observational perspective on the fundamental properties of super-Eddington accretion onto supermassive black holes in quasars. It begins by outlining the selection criteria, particularly focusing on optical and UV broad-line intensity ratios, used to identify a population of unobscured super-Eddington candidates. Several defining features place these candidates at the extreme end of the Population A in main sequence of quasars: among them are the highest observed singly-ionized iron emission, extreme outflow velocities in UV resonance lines, and unusually high metal abundances. These key properties reflect the coexistence of a virialized sub-system within the broad-line region alongside powerful outflows, with the observed gas enrichment likely driven by nuclear or circumnuclear star formation. The most compelling evidence for the occurrence of super-Eddington accretion onto supermassive black holes comes from recent observations of massive black holes at early cosmic epochs. These black holes require rapid growth rates that are only achievable through radiatively inefficient super-Eddington accretion. Furthermore, extreme Eddington ratios, close to or slightly exceeding unity, are consistent with the saturation of radiative output per unit mass predicted by accretion disk theory for super-Eddington accretion rates. The extreme properties of super-Eddington candidates suggest that these quasars could make them stable and well-defined cosmological distance indicators, leveraging the correlation between broad-line width and luminosity expected in virialized systems. Finally, several analogies with accretion processes around stellar-mass black holes, particularly in the high/soft state, are explored to provide additional insight into the mechanisms driving super-Eddington accretion.
title Super-Eddington Accretion in Quasars
topic Astrophysics of Galaxies
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2502.14713