A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
Discovery and analysis of afterglows from poorly localized GRBs with the Gravitational-wave Optical Transient Observer (GOTO) All-sky Survey
Tekijät: Kumar, Amit; Gompertz, B. P.; Schneider, B.; Belkin, S.; Wortley, M. E.; Saccardi, A.; O’Neill, D.; Ackley, K.; Rayson, B.; de Ugarte Postigo, A.; Gulati, A.; Steeghs, D.; Malesani, D. B.; Maund, J. R.; Dyer, M. J.; Giarratana, S.; Serino, M.; Julakanti, Y.; Kumar, B.; Xu, D.; Eyles-Ferris, R. A. J.; Zhu, Z.-P.; Warwick, B.; Hu, Y.-D.; Allen, I.; Ramsay, G.; Starling, R. L. C.; Lyman, J.; Ulaczyk, K.; Godson, B.; Galloway, D. K.; Dhillon, V. S.; O’Brien, P.; Noysena, K.; Kotak, R.; Breton, R. P.; Nuttall, L. K.; Pollacco, D.; Casares, J.; Killestein, T. L.; Kennedy, M. R.; Habeeb, N.; Moran, S.; Wiersema, K.; Worssam, I.; Coppejans, D. L.; Phillips, C. A.; Martin-Carrillo, A.; Pankov, N. S.; Agüí Fernández, J. F.; Aloy, M. A.; An, J.; Anderson, G. E.; Bochenek, A.; Castro-Tirado, A. J.; Chen, X.; Cotter, L.; Dastidar, R.; De Pasquale, M.; D’Elia, V.; Fang, Y.; Fu, S. Y.; Fynbo, J. P. U.; Hartmann, D. H.; He, L. B.; Izzo, L.; Jiang, S. Q.; Kawakubo, Y.; Klunko, E. V.; Levan, A. J.; Liu, X.-W.; Liu, X.; Lombardi, G.; Maiorano, E.; Palmerio, J. T.; Perley, D. A.; Pieterse, D. L. A.; Pozanenko, A. S.; Pugliese, G.; Rossi, A.; Sbarufatti, B.; Bijavara Seshashayana, S.; Tanvir, N. R.; Thöne, C. C.; van der Horst, A. J.; Vergani, S. D.; Volnova, A. A.; Wijers, R. A. M. J.; Wise, J. L.
Kustantaja: Oxford University Press (OUP)
Julkaisuvuosi: 2025
Lehti: Monthly Notices of the Royal Astronomical Society
Vuosikerta: 544
Numero: 2
Aloitussivu: 1541
Lopetussivu: 1587
ISSN: 0035-8711
eISSN: 1365-2966
DOI: https://doi.org/10.1093/mnras/staf1689
Julkaisun avoimuus kirjaamishetkellä: Avoimesti saatavilla
Julkaisukanavan avoimuus : Kokonaan avoin julkaisukanava
Verkko-osoite: https://doi.org/10.1093/mnras/staf1689
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/505571890
Gamma-ray bursts (GRBs), particularly those detected by wide-field instruments such as the Fermi/GBM, pose challenges for optical follow-up because of their large initial localization regions, leaving many GRBs without identified afterglows. The Gravitational-wave Optical Transient Observer (GOTO), with its wide field of view, dual-site coverage, and robotic rapid-response capability, bridges this gap by rapidly identifying and localizing afterglows from alerts issued by space-based facilities including Fermi, SVOM, Swift, and the EP, providing early optical positions for coordinated multiwavelength follow-up. In this paper, we present optical afterglow localization and multiband follow-up of five Fermi/GBM (240619A, 240910A, 240916A, 241002B, and 241228B) and two MAXI/GSC (240122A and 240225B) triggered long GRBs discovered by GOTO in 2024. Spectroscopy for six GRBs (no spectroscopy for GRB 241002B) with VLT/X-shooter and GTC/OSIRIS yields precise redshifts spanning z ≈ 0.40–3.16 and absorption-line diagnostics of hosts and intervening systems. Radio detections for four events (240122A, 240619A, 240910A, and 240916A) confirm the presence of long-lived synchrotron emission. Prompt-emission analysis with Fermi and MAXI data reveals a spectrally hard population, with two bursts lying > 3σ above the Amati relation. Although their optical afterglows resemble those of typical long GRBs, the prompt spectra are consistently harder than the long-GRB average. Broad-band afterglow modelling of six GOTO-discovered GRBs yields jet half-opening angles of a few degrees and beaming-corrected kinetic energies Ejet ∼ 1051–1052 erg, consistent with the canonical long-GRB population. These findings suggest that optical discovery of poorly localized GRBs is likely subject to observational biases favouring luminous events with high spectral peak energy (Ep), while also providing insight into jet microphysics and central engine diversity.
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GOTO project acknowledges support from the Science and Technology Facilities Council (STFC, grant numbers ST/T007184/1, ST/T003103/1, ST/T000406/1, ST/X001121/1 and ST/Z000165/1) and the GOTO consortium institutions; University of Warwick; Monash University; University of Sheffield; University of Leicester; Armagh Observatory & Planetarium; the National Astronomical Research Institute of Thailand (NARIT); University of Manchester; Instituto de Astrofísica de Canarias (IAC); University of Portsmouth; University of Turku.
It is also partly based on data obtained with the instrument OSIRIS, built by a Consortium led by the Instituto de Astrofísica de Canarias in collaboration with the Instituto de Astronomía of the Universidad Autónoma de México. OSIRIS was funded by GRANTECAN and the National Plan of Astronomy and Astrophysics of the Spanish Government.
The ATCA is part of the Australia Telescope National Facility, which is funded by the Australian Government for operation as a National Facility managed by CSIRO.
AK and JRM are supported by the UK Science and Technology Facilities Council (STFC) Consolidated grant ST/V000853/1. BPG acknowledges support from STFC grant No. ST/Y002253/1. BPG and DO acknowledge support from the Leverhulme Trust grant no. RPG-2024-117. BS and SDV acknowledge the support of the French Agence Nationale de la Recherche (ANR), under grant ANR-23-CE31-0011 (project PEGaSUS). DS is supported by the UK Science and Technology Facilities Council (STFC, grant numbers ST/T007184/1, ST/T003103/1, and ST/T000406/1). SG acknowledges support from the Istituto Nazionale di Astrofisica (INAF), project number: 1.05.24.07.04. BK acknowledges support from the ‘Special Project for High-End Foreign Experts,’ Xingdian Funding from Yunnan Province; the Yunnan Key Laboratory of Survey Science (grant 202449CE340002), and National Key Research and Development Program of China (grant 2024YFA1611603). BW is supported by the UKRI’s STFC studentship grant funding, project reference ST/X508871/1. RLCS and SM acknowledge support from the Leverhulme Trust grant RPG-2023-240. NH, POB, and NRT acknowledge support from UKRI/STFC grant ST/W000857/1. JDL acknowledges support from a UK Research and Innovation Future Leaders Fellowship (MR/T020784/1). JC is supported by the Spanish Ministry of Science via the Plan de Generaci\'on de Conocimiento through grant PID2022-143331NB-100. TLK acknowledges a Warwick Astrophysics prize post-doctoral fellowship made possible thanks to a generous philanthropic donation. MAA acknowledges support from grants PID2021-127495NB-I00 (funded by MCIN/AEI/10.13039/501100011033, EU), ASFAE/2022/026 (funded by MCIN, EU NextGenerationEU PRTR-C17.I1), and CIPROM/2022/13 (Generalitat Valenciana). DLC acknowledges support from the UK Science and Technology Facilities Council (STFC) grant number ST/X001121/1. AS acknowledges support by a postdoctoral fellowship from the CNES. AR acknowledges support from the INAF project Supporto Arizona & Italia. AMC and LC acknowledge support from the Irish Research Council Postgraduate Scholarship No. GOIPG/2022/1008. MEW and IW are supported by the UKRI Science and Technology Facilities Council (STFC). DBM is funded by the European Union (ERC, HEAVYMETAL, 101071865).Views and opinions expressed are, however, those of the authors only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them.
The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. NSP and ASP are grateful to the Russian Science Foundation (project no. 23-12-00220) for their partial support of the data reduction, analysis of data. EVK is grateful to the Ministry of Science and Higher Education of the Russian Federation for financial support of this work; the AZT-33IK telescope is part of the Center for Common Use ‘Angara’.
