GRB 241105A: A test case for GRB classification and rapid r-process nucleosynthesis channels

Dimple, Gompertz, BP ORCID: 0000-0002-5826-0548, Levan, AJ, Malesani, DB, Laskar, T, Bala, S, Chrimes, AA ORCID: 0000-0001-9842-6808, Heintz, K ORCID: 0000-0002-9389-7413, Izzo, L, Lamb, GP ORCID: 0000-0001-5169-4143, O'Neill, D, Palmerio, JT ORCID: 0000-0002-9408-1563, Saccardi, A, Anderson, GE ORCID: 0000-0001-6544-8007, De Barra, C, Huang, Y, Kumar, A ORCID: 0000-0002-4870-9436, Li, H, McBreen, S, Mukherjee, O et al (2025) GRB 241105A: A test case for GRB classification and rapid r-process nucleosynthesis channels. Monthly Notices of the Royal Astronomical Society, 544 (1). pp. 548-571. ISSN 0035-8711

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Abstract

Gamma-ray bursts (GRBs) offer a powerful window to probe the progenitor systems responsible for the formation of heavy elements through the rapid neutron capture (r-) process, thanks to their exceptional luminosity, which allows them to be observed across vast cosmic distances. GRB 241105A, observed at a redshift of, features a short initial spike (1.5 s) and a prolonged weak emission lasting about 64 s, positioning it as a candidate for a compact binary merger and potentially marking it as the most distant merger-driven GRB observed to date. However, the emerging ambiguity in GRB classification necessitates further investigation into the burst's true nature. Prompt emission analyses, such as hardness ratio, spectral lag, and minimum variability time-scales, yield mixed classifications, while machine-learning-based clustering places GRB 241105A near both long-duration mergers and collapsar GRBs. We conducted observations using the James Webb Space Telescope (JWST) to search for a potential supernova counterpart. Although no conclusive evidence was found for a supernova, the host galaxy's properties derived from the JWST observations suggest active star formation with low metallicity, and a sub-kpc offset of the afterglow from the host, which appears broadly consistent with a collapsar origin. Nevertheless, a compact binary merger origin cannot be ruled out, as the burst may plausibly arise from a fast progenitor channel. This would have important implications for heavy element enrichment in the early Universe.

Item Type:	Article
Uncontrolled Keywords:	gamma-ray burst: individual: GRB 241105A; gamma-ray bursts; 5101 Astronomical Sciences; 51 Physical Sciences; Machine Learning and Artificial Intelligence; 5101 Astronomical Sciences; 51 Physical Sciences; Machine Learning and Artificial Intelligence; 0201 Astronomical and Space Sciences; Astronomy & Astrophysics; 5101 Astronomical sciences; 5107 Particle and high energy physics; 5109 Space sciences
Subjects:	Q Science > QB Astronomy
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
Date of acceptance:	13 September 2025
Date of first compliant Open Access:	3 June 2026
Date Deposited:	03 Jun 2026 15:07
Last Modified:	03 Jun 2026 15:07
DOI or ID number:	10.1093/mnras/staf1574
URI:	https://researchonline.ljmu.ac.uk/id/eprint/28727

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