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Main Authors: Campana, Sergio, Braito, Valentina, Lazzati, Davide, Tiengo, Andrea
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2408.03306
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author Campana, Sergio
Braito, Valentina
Lazzati, Davide
Tiengo, Andrea
author_facet Campana, Sergio
Braito, Valentina
Lazzati, Davide
Tiengo, Andrea
contents GRB 221009A was the Brightest gamma-ray burst Of All Time (BOAT), surpassing in prompt brightness all GRBs discovered in ~50 yr and in afterglow brightness in ~20 yr. We observed the BOAT with XMM-Newton 2.3 d after the prompt. The X-ray afterglow was still very bright and we collected the largest number of photons with the Reflection Grating Spectrometers (RGS) on a GRB. We searched the RGS data for narrow emission or absorption features. We did not detect any bright line feature. A candidate narrow feature is identified at a (rest-frame) energy of 1.455+0.006-0.014 keV, consistent with an Mg XII Kα emission line, slightly redshifted (0.012) with respect to the host galaxy. We assessed a marginal statistical significance of 3.0sigma for this faint feature based on conservative Monte Carlo simulations, which requires caution for any physical interpretation. If this line feature would be for real, we propose that it might originate from the reflection in the innermost regions of the infalling funnel from low-level late-time activity emission of the central engine.
format Preprint
id arxiv_https___arxiv_org_abs_2408_03306
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A search for soft X-ray emission lines in the afterglow spectrum of GRB 221009A
Campana, Sergio
Braito, Valentina
Lazzati, Davide
Tiengo, Andrea
High Energy Astrophysical Phenomena
GRB 221009A was the Brightest gamma-ray burst Of All Time (BOAT), surpassing in prompt brightness all GRBs discovered in ~50 yr and in afterglow brightness in ~20 yr. We observed the BOAT with XMM-Newton 2.3 d after the prompt. The X-ray afterglow was still very bright and we collected the largest number of photons with the Reflection Grating Spectrometers (RGS) on a GRB. We searched the RGS data for narrow emission or absorption features. We did not detect any bright line feature. A candidate narrow feature is identified at a (rest-frame) energy of 1.455+0.006-0.014 keV, consistent with an Mg XII Kα emission line, slightly redshifted (0.012) with respect to the host galaxy. We assessed a marginal statistical significance of 3.0sigma for this faint feature based on conservative Monte Carlo simulations, which requires caution for any physical interpretation. If this line feature would be for real, we propose that it might originate from the reflection in the innermost regions of the infalling funnel from low-level late-time activity emission of the central engine.
title A search for soft X-ray emission lines in the afterglow spectrum of GRB 221009A
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2408.03306