GCN Circular 34347

Y.-D. Hu, I. Perez-Garcia, E. Fernandez-Garcia, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy and F. J. Aceituno (IAA-CSIC), P. J. Meintjes and H. Van Heerden (UFS, SouthAfrica), A. Martin-Carrillo and L. Hanlon (UCD, Ireland), M. Gritsevich (Univ. of Helsinki) and C. J. Perez del Pulgar (UMA), on behalf of a larger collaboration, report:

Following the detection of GRB 230805B by Swift (Cenko et al. GCNC 34339), the BOOTES-6/DPRT 0.6m robotic telescope at Boyden Observatory in Maselspoort (South Africa) automatically observed the GRB location starting on Aug. 05, 17:15 UT (~ 5.9 h after trigger). No new optical source is detected on the co-added image (7 x 60 s, clear filter) within the enhanced Swift/XRT error region (D'Ai et al. GCNC 34345) down to 19.9 mag.

We also triggered the 1.5m telescope at Observatorio de Sierra Nevada in Granada (Spain), starting on Aug. 05, 20:30 UT (~ 9.1 h after trigger). At the position of the suggested optical afterglow reported by Moskvitin and Goranskij (GCNC 34343) we found a faint optical source for which we preliminary measure I = 22.9+/-0.4 (on a 12 x 150s co-added image), consistent with the fading reported by Malesani and Pursimo in the r-band (GCNC 34346).

We thank both the staff at Boyden and Sierra Nevada Observatories for their excellent support.