Shadow and Quasi-Normal Modes of Schwarzschild-Hernquist Black Hole

Fuente: arXiv
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Autores principales: Feng, Xing-Hui, Zhang, Guang-Yu
Formato: Preprint
Publicado: 2025
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author Feng, Xing-Hui
Zhang, Guang-Yu
author_facet Feng, Xing-Hui
Zhang, Guang-Yu
contents In this paper we study the shadow and quasi-normal modes (QNMs) of a black hole (BH) surrounded by a dark matter halo with Hernquist-type density distribution, which was reported in Ref. \cite{Cardoso:2021wlq}. In astrophysical scenarios, we find that the shadow radius enlarges as the compactness of halo increases. Therefore, we obtain an upper bound for the compactness ${\cal C}\le0.092$ with the Event Horizon Telescope (EHT) observations. We calculate axial gravitational QNMs of the galactic BH up to ${\cal C}\sim{\cal O}(1)$, and fit the redshift relative to Schwarzschild QNMs up to second order in the compactness (for ${\cal C}\le0.3)$. These highly redshifted QNMs, resulting from large compactness, are key to modeling the dark matter halo.
format Preprint
id arxiv_https___arxiv_org_abs_2509_04001
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Shadow and Quasi-Normal Modes of Schwarzschild-Hernquist Black Hole
Feng, Xing-Hui
Zhang, Guang-Yu
General Relativity and Quantum Cosmology
In this paper we study the shadow and quasi-normal modes (QNMs) of a black hole (BH) surrounded by a dark matter halo with Hernquist-type density distribution, which was reported in Ref. \cite{Cardoso:2021wlq}. In astrophysical scenarios, we find that the shadow radius enlarges as the compactness of halo increases. Therefore, we obtain an upper bound for the compactness ${\cal C}\le0.092$ with the Event Horizon Telescope (EHT) observations. We calculate axial gravitational QNMs of the galactic BH up to ${\cal C}\sim{\cal O}(1)$, and fit the redshift relative to Schwarzschild QNMs up to second order in the compactness (for ${\cal C}\le0.3)$. These highly redshifted QNMs, resulting from large compactness, are key to modeling the dark matter halo.
title Shadow and Quasi-Normal Modes of Schwarzschild-Hernquist Black Hole
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2509.04001