GCN Circular 34841
Subject
GRB 231017A: GOTO optical upper limits
Date
2023-10-19T16:24:59Z (9 months ago)
From
Ben Gompertz at U of Birmingham <b.gompertz@bham.ac.uk>
Via
email
S. Belkin; K. Ackley; A. Kumar; B. P. Gompertz; B. Godson; R. Starling; M. J. Dyer; J. Lyman; K. Ulaczyk; F. Jimenez-Ibarra; D. O'Neill; D. Steeghs; D. K. Galloway; V. Dhillon; P. O'Brien; G. Ramsay; K. Noysena; R. Kotak; R. P. Breton; L. K. Nuttall; E. Pall'e and D. Pollacco report on behalf of the GOTO collaboration:
We report on observations with the Gravitational-wave Optical Transient Observer (GOTO; Steeghs et al. 2022) in response to GRB 231017A (Fermi GBM team, GCN 34822). Targeted observations were performed between 00:20:50 UT on 2023-10-18 and 02:37:04 UT on 2023-10-18 (starting ~16.25 hours after trigger). Each observation consisted of 4x90s exposures in the GOTO L-band (400-700 nm).
We identify no candidate optical counterparts within the Swift/BAT-GUANO localisation region (DeLaunay et al., GCN 34824) or at the positions of the 9 sources identified in XRT pointed observations (Evans et al., GCN 34825; Dichiara et al., GCN 34829). The mean 5-sigma limiting magnitude was L > 20.2 mag. This result is consistent with other observations (Kumar et al., GCN 34833; Strausbaugh et al., GCN 34834; Shrestha et al., GCN 34836; Xu et al., GCN 34840