TITLE:   GCN CIRCULAR
NUMBER:  36883
SUBJECT: GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
DATE:    24/07/16 10:03:27 GMT
FROM:    Dong Xu at NAOC/CAS <dxu@nao.cas.cn>

S. Tinyanont, R. Anutarawiramkul, P. Butpan (NARIT), J. An, X. Liu, S.Q. Jiang, S.Y. Fu, Z.P. Zhu, D. Xu, Z. Fan, W.X. Li, N.C. Sun, Y.N. Wang (NAOC) report on behalf of a large collaboration:

We observed the field of short-hard GRB 240715A detected by Fermi/GBM (Fermi GBM team, GCN 36866), IPN (Kozyrev et al., GCN 36872), and SVOM/GRM (Huang et al., GCN 36881) using the 0.7-m telescope of the Thai Robotic Telescope (TRT) network, located at Cerro Tololo, Chile. We obtained 3 x 300 s R-band frames at a median time 24.0 hr after the Fermi trigger.

We observed the "Good" one (R.A. = 00h20m35.12s, Dec.=-36°23′22.4″) of the three Swift/XRT candidates (https://www.swift.ac.uk/ToO_GRBs/00021699/). No new optical source is detected in the stacked image at the XRT position, down to a 5-sigma limiting magnitude of R ~ 20.7, calibrated with SkyMapper stars and not corrected for Galactic extinction.