Self-consistent spherical accretion simulations show cooling-enhanced growth of PBHs with radiative efficiency ~10^{-2} in the bremsstrahlung regime, yielding a critical seed mass of ~10^{-16} M_sun to consume a solar-mass star in a Hubble time.
Active galactic nuclei flicker: an observational estimate of the duration of black hole growth phases of ~1e5 years
4 Pith papers cite this work. Polarity classification is still indexing.
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abstract
We present an observational constraint for the typical active galactic nucleus (AGN) phase lifetime. The argument is based on the time lag between an AGN central engine switching on and becoming visible in X-rays, and the time the AGN then requires to photoionize a large fraction of the host galaxy. Based on the typical light travel time across massive galaxies, and the observed fraction of X-ray selected AGN without AGN-photoionized narrow lines, we estimate that the AGN phase typically lasts $\sim10^{5}$ years. This lifetime is short compared to the total growth time of $10^{7}-10^{9}$ years estimated from e.g. the Soltan argument and implies that black holes grow via many such short bursts and that AGN therefore "flicker" on and off. We discuss some consequences of this flickering behavior for AGN feedback and the analogy of X-ray binaries and AGN lifecycles.
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VLA radio-selected LLAGN show 84% optical, 63% X-ray, and 13% infrared detection rates, with black holes ~0.7 dex smaller, accretion rates ~4.2 dex lower, and host galaxies ~0.3 dex lower in stellar mass with ~0.5 dex suppressed star formation than Swift-BAT AGN.
SKAO will trace synchrotron jets, thermal emission, and low-column-density HI gas in nearby AGN to characterize duty cycles and multi-phase feeding/feedback linked to star formation.
Overview chapter summarizing traditional orientation-based and radiation-regulated unification models for AGN, including evolutionary aspects and changing-look AGN.
citing papers explorer
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Accretion of Primordial Black Holes in Stellar Interiors
Self-consistent spherical accretion simulations show cooling-enhanced growth of PBHs with radiative efficiency ~10^{-2} in the bremsstrahlung regime, yielding a critical seed mass of ~10^{-16} M_sun to consume a solar-mass star in a Hubble time.
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Nuclear Activity and Host Galaxy Properties of Low-Luminosity AGN Identified from VLA Observations
VLA radio-selected LLAGN show 84% optical, 63% X-ray, and 13% infrared detection rates, with black holes ~0.7 dex smaller, accretion rates ~4.2 dex lower, and host galaxies ~0.3 dex lower in stellar mass with ~0.5 dex suppressed star formation than Swift-BAT AGN.
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AGN Feeding & Feedback Over the Galactic Scales
SKAO will trace synchrotron jets, thermal emission, and low-column-density HI gas in nearby AGN to characterize duty cycles and multi-phase feeding/feedback linked to star formation.
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Unification models of Active Galactic Nuclei
Overview chapter summarizing traditional orientation-based and radiation-regulated unification models for AGN, including evolutionary aspects and changing-look AGN.