GRB 230911A: The First Discovery of a Fermi GRB Optical Counterpart with the Gravitational-wave Optical Transient Observer (GOTO)

S. Belkin, B. P. Gompertz, A. Kumar, K. Ackley, D. K. Galloway, F. Jiménez-Ibarra, T. l. Killestein, D. O’Neill, K. Wiersema, D. B. Malesani, A. j. Levan, J. Lyman, M. J. Dyer, K. Ulaczyk, D. Steeghs, V. S. Dhillon, P. O’Brien, G. Ramsay, K. Noysena, R. KotakR. P. Breton, L. Nuttall, E. Pallé, D. Pollacco, S. Awiphan, U. Burhanudin, P. Chote, A. Chrimes, E. Daw, C. Duffy, R. Eyles-Ferris, B. Godson, T. Heikkilä, P. Irawati, L. Kelsey, M. R. Kennedy, S. Littlefair, L. Makrygianni, T. Marsh, D. Mata sánchez, S. Mattila, J. Maund, J. McCormac, D. Mkrtichian, J. Mullaney, M. Patel, J. Rana, E. Rol, U. Sawangwit, E. Stanway, R. Starling, P. A. Strøm, B. Warwick

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We report on the detection of candidate optical counterpart GOTO23akf/AT2023shv to the GRB 230911A with the Gravitational-wave Optical Transient Observer (GOTO) instruments located at La Palma, Canary Islands, and Siding Spring Observatory, Australia. The Fermi Gamma-ray Burst Monitor, which finds gamma-ray bursts (GRBs) nearly every two days, detected GRB 230911A with a statistical uncertainty of 4fdg1. However, the large (∼10–100 deg2) localization areas mostly impede the rapid identification of an optical counterpart. GOTO facilities fully covered 90% localization area of the GRB 230911A. We proposed GOTO23akf as the optical afterglow of GRB 230911A, subsequently confirmed through Swift-X-Ray Telescope observations in which an uncatalogued X-ray source spatially coincident with the GOTO candidate was detected. This is the first optical afterglow discovery for a Fermi GRB with the newly expanded GOTO network.
Original languageEnglish
Article number6
Number of pages9
JournalResearch Notes of the AAS
Issue number1
Publication statusPublished - 4 Jan 2024

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