Exploring lensing signatures through spectrotemporal correlations: implications for black hole parameter estimation

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Hauptverfasser: Harikesh, Sreehari, Hadar, Shahar, Chelouche, Doron
Format: Preprint
Veröffentlicht: 2025
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author Harikesh, Sreehari
Hadar, Shahar
Chelouche, Doron
author_facet Harikesh, Sreehari
Hadar, Shahar
Chelouche, Doron
contents Extreme gravitational lensing and relativistic frequency shifts, combined together, imply that radiation emitted from a black hole's vicinity can echo at different frequencies and times, leading to spectrotemporal correlations in observed signals. If such correlations are uncovered by future observations, they could provide a probe of the spacetime geometry in the strong-field region near black holes. Here, motivated by these prospects, we numerically compute the two-point correlation function of specific flux fluctuations in a simple model of line emission by a hotspot in an equatorial circular orbit. We make use of the Adaptive Analytical Ray Tracing (AART) code to generate the light curves we then correlate. Our results for the correlation maps show a clear decomposition into direct emission-dominated, and lensing-dominated contributions. The computation transcends past analytical approximations, studying the main contribution to the correlation function, which is not deep in the universal regime. We compute correlation maps for many combinations of black hole mass, spin, inclination, hotspot width, and orbital radius, and study their dependence on these parameters. The correlation maps are then used to train convolutional neural networks which can be used to estimate source parameters, achieving promisingly low evaluation errors within the model. Our results could be relevant for future X-ray spectroscopic missions, offering insights into black hole parameter inference.
format Preprint
id arxiv_https___arxiv_org_abs_2502_12053
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Exploring lensing signatures through spectrotemporal correlations: implications for black hole parameter estimation
Harikesh, Sreehari
Hadar, Shahar
Chelouche, Doron
High Energy Astrophysical Phenomena
Instrumentation and Methods for Astrophysics
General Relativity and Quantum Cosmology
Extreme gravitational lensing and relativistic frequency shifts, combined together, imply that radiation emitted from a black hole's vicinity can echo at different frequencies and times, leading to spectrotemporal correlations in observed signals. If such correlations are uncovered by future observations, they could provide a probe of the spacetime geometry in the strong-field region near black holes. Here, motivated by these prospects, we numerically compute the two-point correlation function of specific flux fluctuations in a simple model of line emission by a hotspot in an equatorial circular orbit. We make use of the Adaptive Analytical Ray Tracing (AART) code to generate the light curves we then correlate. Our results for the correlation maps show a clear decomposition into direct emission-dominated, and lensing-dominated contributions. The computation transcends past analytical approximations, studying the main contribution to the correlation function, which is not deep in the universal regime. We compute correlation maps for many combinations of black hole mass, spin, inclination, hotspot width, and orbital radius, and study their dependence on these parameters. The correlation maps are then used to train convolutional neural networks which can be used to estimate source parameters, achieving promisingly low evaluation errors within the model. Our results could be relevant for future X-ray spectroscopic missions, offering insights into black hole parameter inference.
title Exploring lensing signatures through spectrotemporal correlations: implications for black hole parameter estimation
topic High Energy Astrophysical Phenomena
Instrumentation and Methods for Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2502.12053