TITLE: GCN CIRCULAR NUMBER: 34836 SUBJECT: GRB 231017A: Las Cumbres optical upper limit DATE: 23/10/18 23:23:48 GMT FROM: Manisha Shrestha at University of Arizona <mshrestha1@arizona.edu> M. Shrestha (Univ. of Arizona), D. Sand (Univ. of Arizona), K. D. Alexander (Univ. of Arizona), J. Andrews (Gemini), J. Pearson (Univ. of Arizona), N. Smith (Univ. of Arizona), K. Bostroem (Univ. of Arizona) D. A. Howell (LCO/UCSB), C. McCully (LCO/UCSB), M. Newsome (LCO/UCSB), E Padilla Gonzalez (LCO/UCSB), C. Pellegrino (LCO/UCSB), G. Terreran (LCO/UCSB), J. Farah (LCO/UCSB) report on behalf of a wider Global Supernova Project collaboration: We observed the field of GRB 231017A (Fermi GBM team GCN 34822, Trigger 719222708) localized by Swift/BAT-GUANO (DeLaunay et al. GCN 34824) with the 1-m telescope, on 2023-10-18T02:56:38.021 UT (60235.12 MJD, ~0.8 days after the trigger) using the Sinistro instrument in V, g, r, i bands. We do not detect any new optical counterpart within the error region of BAT-GUANO with upper limit of: g> 22.5 r> 21.2 i> 20.9 These values were calculated with respect to ATLAS-REFCAT2 (Tonry et al. 2018, ApJ 867 105) catalog are not corrected for galactic extinction. This non-detection is in agreement with Strausbaugh et al., GCN 34834 and Kumar et al., GCN 34833. View this GCN Circular online at https://gcn.nasa.gov/circulars/34836. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...