Implications of Non-equatorial Relativistic Accretion Flows for Ultra-Fast Inflows in AGNs

Fuente: arXiv
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Autori principali: Fukumura, Keigo, Peca, Alessandro, Serafinelli, Roberto, Dadina, Mauro
Natura: Preprint
Pubblicazione: 2026
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author Fukumura, Keigo
Peca, Alessandro
Serafinelli, Roberto
Dadina, Mauro
author_facet Fukumura, Keigo
Peca, Alessandro
Serafinelli, Roberto
Dadina, Mauro
contents Motivated by a number of X-ray observations of active galactic nuclei (AGNs) that exhibit a potential signature of ultra-fast inflows (UFIs), we consider in this work a scenario that UFIs can be physically identified as weakly-magnetized hydrodynamic accretion flows that is guided and channeled by poloidal magnetic field into low-to-mid latitude above the equatorial disk. In the context of general relativistic hydrodynamics (GRHD) under a weak-field limit in Kerr spacetime, we present a set of preliminary results by numerically calculating the physical property of GRHD flows (e.g. kinematics and density distribution) in an effort to simulate redshifted absorption line spectra. Our model demonstrates that such GRHD accretion off the equatorial plane (i.e. $v \gsim 0.1c$ where $c$ is the speed of light in the vicinity of AGN closer than $\sim 100$ \sw radii) can manifest itself as UFIs in the form of redshifted absorption signature assuming the observed characteristics such as column density of $N_H \sim 10^{23}$ cm$^{-2}$ and ionization parameter of $\log (ξ\rm{[erg~cm~s^{-1}])} \sim 3$ as also seen in recent multi-epoch {\it NuSTAR} observations among other data.
format Preprint
id arxiv_https___arxiv_org_abs_2601_04141
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Implications of Non-equatorial Relativistic Accretion Flows for Ultra-Fast Inflows in AGNs
Fukumura, Keigo
Peca, Alessandro
Serafinelli, Roberto
Dadina, Mauro
High Energy Astrophysical Phenomena
Motivated by a number of X-ray observations of active galactic nuclei (AGNs) that exhibit a potential signature of ultra-fast inflows (UFIs), we consider in this work a scenario that UFIs can be physically identified as weakly-magnetized hydrodynamic accretion flows that is guided and channeled by poloidal magnetic field into low-to-mid latitude above the equatorial disk. In the context of general relativistic hydrodynamics (GRHD) under a weak-field limit in Kerr spacetime, we present a set of preliminary results by numerically calculating the physical property of GRHD flows (e.g. kinematics and density distribution) in an effort to simulate redshifted absorption line spectra. Our model demonstrates that such GRHD accretion off the equatorial plane (i.e. $v \gsim 0.1c$ where $c$ is the speed of light in the vicinity of AGN closer than $\sim 100$ \sw radii) can manifest itself as UFIs in the form of redshifted absorption signature assuming the observed characteristics such as column density of $N_H \sim 10^{23}$ cm$^{-2}$ and ionization parameter of $\log (ξ\rm{[erg~cm~s^{-1}])} \sim 3$ as also seen in recent multi-epoch {\it NuSTAR} observations among other data.
title Implications of Non-equatorial Relativistic Accretion Flows for Ultra-Fast Inflows in AGNs
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2601.04141