Fast X-ray Transient Detection with AXIS: application to Magnetar Giant Flares

Fuente: arXiv
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Main Authors: Negro, Michela, Wadiasingh, Zorawar, Younes, George, Burns, Eric, Patel, Anirudh, Metzger, Brian D., Thompson, Todd A., Haggard, Daryl, Cenko, S. Bradley
Format: Preprint
Published: 2025
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author Negro, Michela
Wadiasingh, Zorawar
Younes, George
Burns, Eric
Patel, Anirudh
Metzger, Brian D.
Thompson, Todd A.
Haggard, Daryl
Cenko, S. Bradley
author_facet Negro, Michela
Wadiasingh, Zorawar
Younes, George
Burns, Eric
Patel, Anirudh
Metzger, Brian D.
Thompson, Todd A.
Haggard, Daryl
Cenko, S. Bradley
contents Magnetar giant flares (MGFs) are among the most luminous high-energy transients in the local universe, consisting of a short, intense MeV gamma-ray spike followed by a softer, pulsating X-ray tail and possibly delayed radioactive emission. While only three Galactic events have been firmly detected, several extragalactic candidates have recently been reported, motivating the need for sensitive, rapid-response gamma- and X-ray facilities to constrain their rates and energetics. We present a feasibility study of detecting MGFs with the Advanced X-ray Imaging Satellite (AXIS), focusing on two complementary pathways: (i) serendipitous discovery of the prompt gamma-ray spike within the field of view, and (ii) rapid follow-up of MGF tails in nearby galaxies. Using sensitivity rescaling and volumetric rate estimates, we find that serendipitous detection of prompt spikes during the mission lifetime is possible but unlikely, primarily because of their short duration and primarily because of their short duration and hard spectrum, in the assumption that the hard gamma-ray spectrum can be reliably extrapolated to the instrument's energy range. In contrast, AXIS's superior sensitivity, if accompanied by fast repointing capabilities, offer an extraordinary opportunity to detect pulsating X-ray tails out to about 20 Mpc, enabling the first extragalactic measurements of periodic modulations from a magnetar and potentially constraining emission geometry and fireball physics. Finally, we evaluate the detectability of soft X-ray line emission from r-process nucleosynthesis in MGFs, finding that such signals are extremely faint and confining the detection to Galactic distances. Our study offer a general framework for assessing the detectability of short transients with future missions.
format Preprint
id arxiv_https___arxiv_org_abs_2509_03763
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fast X-ray Transient Detection with AXIS: application to Magnetar Giant Flares
Negro, Michela
Wadiasingh, Zorawar
Younes, George
Burns, Eric
Patel, Anirudh
Metzger, Brian D.
Thompson, Todd A.
Haggard, Daryl
Cenko, S. Bradley
High Energy Astrophysical Phenomena
Magnetar giant flares (MGFs) are among the most luminous high-energy transients in the local universe, consisting of a short, intense MeV gamma-ray spike followed by a softer, pulsating X-ray tail and possibly delayed radioactive emission. While only three Galactic events have been firmly detected, several extragalactic candidates have recently been reported, motivating the need for sensitive, rapid-response gamma- and X-ray facilities to constrain their rates and energetics. We present a feasibility study of detecting MGFs with the Advanced X-ray Imaging Satellite (AXIS), focusing on two complementary pathways: (i) serendipitous discovery of the prompt gamma-ray spike within the field of view, and (ii) rapid follow-up of MGF tails in nearby galaxies. Using sensitivity rescaling and volumetric rate estimates, we find that serendipitous detection of prompt spikes during the mission lifetime is possible but unlikely, primarily because of their short duration and primarily because of their short duration and hard spectrum, in the assumption that the hard gamma-ray spectrum can be reliably extrapolated to the instrument's energy range. In contrast, AXIS's superior sensitivity, if accompanied by fast repointing capabilities, offer an extraordinary opportunity to detect pulsating X-ray tails out to about 20 Mpc, enabling the first extragalactic measurements of periodic modulations from a magnetar and potentially constraining emission geometry and fireball physics. Finally, we evaluate the detectability of soft X-ray line emission from r-process nucleosynthesis in MGFs, finding that such signals are extremely faint and confining the detection to Galactic distances. Our study offer a general framework for assessing the detectability of short transients with future missions.
title Fast X-ray Transient Detection with AXIS: application to Magnetar Giant Flares
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2509.03763