Systematic Collapse of the Accretion Disc Across the Supermassive Black Hole Population

Fuente: arXiv
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Main Authors: Hagen, Scott, Done, Chris, Silverman, John D., Li, Junyao, Liu, Teng, Ren, Wenke, Buchner, Johannes, Merloni, Andrea, Nagao, Tohru, Salvato, Mara
Format: Preprint
Published: 2024
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author Hagen, Scott
Done, Chris
Silverman, John D.
Li, Junyao
Liu, Teng
Ren, Wenke
Buchner, Johannes
Merloni, Andrea
Nagao, Tohru
Salvato, Mara
author_facet Hagen, Scott
Done, Chris
Silverman, John D.
Li, Junyao
Liu, Teng
Ren, Wenke
Buchner, Johannes
Merloni, Andrea
Nagao, Tohru
Salvato, Mara
contents The structure of the accretion flow onto supermassive black holes (SMBH) is not well understood. Standard disc models match to zeroth order in predicting substantial energy dissipation within optically-thick material producing a characteristic strong blue/UV continuum. However they fail at reproducing more detailed comparisons to the observed spectral shapes along with their observed variability. Based on stellar mass black holes within our galaxy, accretion discs should undergo a transition into an X-ray hot, radiatively inefficient flow, below a (mass scaled) luminosity of $\sim 0.02\,L_{\rm{Edd}}$. While this has been seen in limited samples of nearby low-luminosity active galactic nuclei (AGN) and a few rare changing-look AGN, it is not at all clear whether this transition is present in the wider AGN population across cosmic time. A key issue is the difficulty in disentangling a change in spectral state from increased dust obscuration and/or host galaxy contamination, effectively drowning out the AGN emission. Here we use the new eROSITA eFEDS Survey to identify unobscured AGN from their X-ray emission, matched to excellent optical imaging from Subaru's Hyper Suprime-Cam; allowing the subtraction of the host galaxy contamination. The resulting, uncontaminated, AGN spectra reveal a smooth transition from a strongly disc dominated state in bright AGN, to the collapse of the disc into an inefficient X-ray plasma in the low luminosity AGN, with the transition occurring at $\sim 0.02\,L_{\rm{Edd}}$; revealing fundamental aspects of accretion physics in AGN.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06674
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Systematic Collapse of the Accretion Disc Across the Supermassive Black Hole Population
Hagen, Scott
Done, Chris
Silverman, John D.
Li, Junyao
Liu, Teng
Ren, Wenke
Buchner, Johannes
Merloni, Andrea
Nagao, Tohru
Salvato, Mara
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
The structure of the accretion flow onto supermassive black holes (SMBH) is not well understood. Standard disc models match to zeroth order in predicting substantial energy dissipation within optically-thick material producing a characteristic strong blue/UV continuum. However they fail at reproducing more detailed comparisons to the observed spectral shapes along with their observed variability. Based on stellar mass black holes within our galaxy, accretion discs should undergo a transition into an X-ray hot, radiatively inefficient flow, below a (mass scaled) luminosity of $\sim 0.02\,L_{\rm{Edd}}$. While this has been seen in limited samples of nearby low-luminosity active galactic nuclei (AGN) and a few rare changing-look AGN, it is not at all clear whether this transition is present in the wider AGN population across cosmic time. A key issue is the difficulty in disentangling a change in spectral state from increased dust obscuration and/or host galaxy contamination, effectively drowning out the AGN emission. Here we use the new eROSITA eFEDS Survey to identify unobscured AGN from their X-ray emission, matched to excellent optical imaging from Subaru's Hyper Suprime-Cam; allowing the subtraction of the host galaxy contamination. The resulting, uncontaminated, AGN spectra reveal a smooth transition from a strongly disc dominated state in bright AGN, to the collapse of the disc into an inefficient X-ray plasma in the low luminosity AGN, with the transition occurring at $\sim 0.02\,L_{\rm{Edd}}$; revealing fundamental aspects of accretion physics in AGN.
title Systematic Collapse of the Accretion Disc Across the Supermassive Black Hole Population
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2406.06674