Observational signatures and polarized images of rotating charged black holes in Kalb-Ramond Gravity

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Yang, Chen-Yu, He, Ke-Jian, Zeng, Xiao-Xiong, Li, Li-Fang
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866908483867115520
author Yang, Chen-Yu
He, Ke-Jian
Zeng, Xiao-Xiong
Li, Li-Fang
author_facet Yang, Chen-Yu
He, Ke-Jian
Zeng, Xiao-Xiong
Li, Li-Fang
contents This paper investigates the shadow images of rotating charged black holes in Kalb-Ramond (KR) gravity, using an accretion disk that is both optically and geometrically thin and located on the equatorial plane as the light source model. The results show that, compared to Sgr A*, the observational data of M87* impose stronger constraints on the charge parameter Q and the Lorentz-violating parameter G. Under the thin accretion disk model, a larger observer inclination theta_o deforms the inner shadow into a hat-like structure. The parameters (a, Q, G) mainly affect the size of the inner shadow and the brightness of the critical curve, where increasing these parameters reduces the shadow size and enhances the distinguishability of the critical curve. In the retrograde accretion disk case, the gravitational redshift significantly reduces the observed brightness of the image. In addition, we compute the distribution of the redshift factor on the projection screen. The results indicate that the Doppler effect induced by large theta_o enhances the blueshift in the image, while the light emitted by particles plunging into the black hole leads to strong redshift near the inner shadow. Finally, we study the polarization images under synchrotron radiation and find that the polarization intensity P_o reaches its maximum around the lensed image and higher-order images, whereas no polarization vectors appear within the inner shadow. This stands in sharp contrast to horizonless compact objects. These findings contribute to a deeper understanding of the shadow properties of charged black holes within Lorentz-violating gravity.
format Preprint
id arxiv_https___arxiv_org_abs_2508_07393
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Observational signatures and polarized images of rotating charged black holes in Kalb-Ramond Gravity
Yang, Chen-Yu
He, Ke-Jian
Zeng, Xiao-Xiong
Li, Li-Fang
General Relativity and Quantum Cosmology
This paper investigates the shadow images of rotating charged black holes in Kalb-Ramond (KR) gravity, using an accretion disk that is both optically and geometrically thin and located on the equatorial plane as the light source model. The results show that, compared to Sgr A*, the observational data of M87* impose stronger constraints on the charge parameter Q and the Lorentz-violating parameter G. Under the thin accretion disk model, a larger observer inclination theta_o deforms the inner shadow into a hat-like structure. The parameters (a, Q, G) mainly affect the size of the inner shadow and the brightness of the critical curve, where increasing these parameters reduces the shadow size and enhances the distinguishability of the critical curve. In the retrograde accretion disk case, the gravitational redshift significantly reduces the observed brightness of the image. In addition, we compute the distribution of the redshift factor on the projection screen. The results indicate that the Doppler effect induced by large theta_o enhances the blueshift in the image, while the light emitted by particles plunging into the black hole leads to strong redshift near the inner shadow. Finally, we study the polarization images under synchrotron radiation and find that the polarization intensity P_o reaches its maximum around the lensed image and higher-order images, whereas no polarization vectors appear within the inner shadow. This stands in sharp contrast to horizonless compact objects. These findings contribute to a deeper understanding of the shadow properties of charged black holes within Lorentz-violating gravity.
title Observational signatures and polarized images of rotating charged black holes in Kalb-Ramond Gravity
topic General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2508.07393