A comprehensive broadband analysis of the high-redshift GRB 240218A
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00619120" target="_blank" >RIV/67985815:_____/25:00619120 - isvavai.cz</a>
Result on the web
<a href="https://hdl.handle.net/11104/0365886" target="_blank" >https://hdl.handle.net/11104/0365886</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1051/0004-6361/202452748" target="_blank" >10.1051/0004-6361/202452748</a>
Alternative languages
Result language
angličtina
Original language name
A comprehensive broadband analysis of the high-redshift GRB 240218A
Original language description
The detection and follow-up observations of high-redshift (z > 6) gamma-ray bursts (GRBs) provide a unique opportunity to explore the properties of the distant Universe. Unfortunately, they are rather rare, with only a dozen of them identified so far. Aims. We present here the discovery of the GRB with the second highest spectroscopic redshift measured to date, GRB 240218A at z = 6.782, and the broadband analysis of its afterglow. Following the detection by high-energy satellites, we obtained multi-epoch and multi-wavelength photometric follow-up observations, from 68 s to similar to 48 d after the detection. These data allow us to perform a comprehensive study of the emission and physical properties of this event. We also compare these properties with GRBs observed at high and low redshift. Methods. We built the X-ray, near-infrared, and radio light curves and studied their temporal evolution. Moreover, we investigated the spectral energy distribution (SED) at different times to trace possible spectral evolution. We also compared the prompt phase properties, X-ray luminosity, and optical extinction of GRB 240218A with those of the long-duration GRB (LGRB) population. Results. The SED analysis reveals a typical afterglow-like behaviour at late times. The origin of the early-time emission is uncertain, with the probable presence of an additional contribution on top of the afterglow emission. From the broadband physical modelling of the afterglow, we identify a narrow Gaussian jet seen slightly off-axis, theta(v) = 2.52(-0.29)(+0.57) deg, and pinpoint the presence of a possible jet break similar to 0.86 d after the trigger. Conclusions. The results of the analysis and the comparison with other high-z GRBs reveal that we can consider GRB 240218A as a 'standard' high-redshift LGRB: the prompt phase properties, the X-ray luminosity, and the optical extinction are consistent with the values derived for the LGRB population. The jet opening angle is narrower but compatible with those of high-z bursts, possibly pointing to more collimated jets at high redshift.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10308 - Astronomy (including astrophysics,space science)
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2025
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astronomy & Astrophysics
ISSN
0004-6361
e-ISSN
1432-0746
Volume of the periodical
695
Issue of the periodical within the volume
March
Country of publishing house
FR - FRANCE
Number of pages
22
Pages from-to
A239
UT code for WoS article
001452581300027
EID of the result in the Scopus database
2-s2.0-105001651638