Soft X-ray prompt emission from a high-redshift gamma-ray burst EP240315a

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2404.16425v1.pdf (5.98 MB)

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http://arxiv.org/abs/2404.16425

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https://doi.org/10.48550/arXiv.2404.16425
 http://hdl.handle.net/11603/33932

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UMBC Faculty Collection
UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)

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Author/Creator ORCID

https://orcid.org/0000-0002-4299-2517

Date

2024-04-25

Type of Work

journal articles
preprint
Text

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Citation of Original Publication

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CC BY-NC-ND 4.0 DEED Attribution-NonCommercial-NoDerivs 4.0 International

Subjects

Astrophysics - High Energy Astrophysical Phenomena

Abstract

Long gamma-ray bursts (GRBs) are believed to originate from core collapse of massive stars. High-redshift GRBs can probe the star formation and reionization history of the early universe, but their detection remains rare. Here we report the detection of a GRB triggered in the 0.5--4 keV band by the Wide-field X-ray Telescope (WXT) on board the Einstein Probe (EP) mission, designated as EP240315a, whose bright peak was also detected by the Swift Burst Alert Telescope and Konus-Wind through off-line analyses. At a redshift of z=4.859, EP240315a showed a much longer and more complicated light curve in the soft X-ray band than in gamma-rays. Benefiting from a large field-of-view (∼3600 deg²) and a high sensitivity, EP-WXT captured the earlier engine activation and extended late engine activity through a continuous detection. With a peak X-ray flux at the faint end of previously known high-z GRBs, the detection of EP240315a demonstrates the great potential for EP to study the early universe via GRBs.