Illuminating gravitational wave sources with Sgr A* flares

Fuente: arXiv
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Main Author: Seoane, Pau Amaro
Format: Preprint
Published: 2025
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author Seoane, Pau Amaro
author_facet Seoane, Pau Amaro
contents Sagittarius A* exhibits daily energetic flares characterized by non-thermal emission in the infrared and X-ray bands. While the underlying accretion flow is a Radiatively Inefficient Accretion Flow (RIAF) peaking at radio frequencies, the mechanism powering these non-thermal transients remains debated. Stellar dynamics predict a population of faint brown dwarfs orbiting Sgr A*. We investigate whether the tidal stripping of brown dwarfs provides a viable fueling mechanism for the observed flares. These objects are progenitors of Extremely Large Mass Ratio Inspirals (XMRIs), crucial sources of low-frequency gravitational waves for the future LISA mission. We present high-resolution hydrodynamic simulations of grazing tidal interactions coupled with a parameterized non-thermal radiation model. We numerically model the stripping of the brown dwarf envelope and the subsequent accretion of this material. We demonstrate that the dynamics of the tidal fallback and subsequent viscous evolution naturally reproduce the fundamental temporal characteristics of observed flares: the peak luminosity and the characteristic 1-hour duration. We show that this fueling mechanism is dynamically viable and energetically consistent, placing strong constraints on the required efficiency of the non-thermal emission process, suggesting extreme radiative inefficiency. These findings provide compelling evidence for a hidden population of brown dwarfs in the Galactic Center. Crucially, the observed high flare frequency implies tight orbits characteristic of advanced inspirals. This establishes a direct link between electromagnetic transients and active gravitational wave sources, alerting the LISA consortium years in advance to the presence of specific XMRI systems promising exceptionally high signal-to-noise ratios for precision tests of general relativity.
format Preprint
id arxiv_https___arxiv_org_abs_2510_20898
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Illuminating gravitational wave sources with Sgr A* flares
Seoane, Pau Amaro
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
General Relativity and Quantum Cosmology
Sagittarius A* exhibits daily energetic flares characterized by non-thermal emission in the infrared and X-ray bands. While the underlying accretion flow is a Radiatively Inefficient Accretion Flow (RIAF) peaking at radio frequencies, the mechanism powering these non-thermal transients remains debated. Stellar dynamics predict a population of faint brown dwarfs orbiting Sgr A*. We investigate whether the tidal stripping of brown dwarfs provides a viable fueling mechanism for the observed flares. These objects are progenitors of Extremely Large Mass Ratio Inspirals (XMRIs), crucial sources of low-frequency gravitational waves for the future LISA mission. We present high-resolution hydrodynamic simulations of grazing tidal interactions coupled with a parameterized non-thermal radiation model. We numerically model the stripping of the brown dwarf envelope and the subsequent accretion of this material. We demonstrate that the dynamics of the tidal fallback and subsequent viscous evolution naturally reproduce the fundamental temporal characteristics of observed flares: the peak luminosity and the characteristic 1-hour duration. We show that this fueling mechanism is dynamically viable and energetically consistent, placing strong constraints on the required efficiency of the non-thermal emission process, suggesting extreme radiative inefficiency. These findings provide compelling evidence for a hidden population of brown dwarfs in the Galactic Center. Crucially, the observed high flare frequency implies tight orbits characteristic of advanced inspirals. This establishes a direct link between electromagnetic transients and active gravitational wave sources, alerting the LISA consortium years in advance to the presence of specific XMRI systems promising exceptionally high signal-to-noise ratios for precision tests of general relativity.
title Illuminating gravitational wave sources with Sgr A* flares
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2510.20898