TITLE:   GCN CIRCULAR
NUMBER:  38095
SUBJECT: GRB 240511A: LCO upper limits
DATE:    24/11/06 08:25:43 GMT
FROM:    ankur ghosh at ARIES <ghosh.ankur1994@gmail.com>

Ankur Ghosh, Soebur Razzaque (CAPP, University of Johannesburg), Alexander Moskvitin, Yulia Sotnikova (SAO RAS) report on behalf of a larger collaboration.

We observed the field of GRB 240511A (The Fermi GBM team, GCN 36428; Laha et al., GCN 36430; Evans, GCN 36431; Salvaggio et al., GCN 36443; Evans et al., GCN 36446; Krimm et al., GCN 36459) using the 1-meter Sinistro telescope at the Las Cumbres Observatory Global Telescope (LCOGT) node located at SAAO, South Africa. The telescope is equipped with a CCD (FOV: 13 x 13 arcmin, scale: 0.39 arcsec/pixel) and V, R filters. Observations began on May 12, starting 8.8269 hours after the GRB trigger.

We did not detect the optical transient (OT) reported by Malesani and Milvang-Jensen (GCN 36442) and de Ugarte Postigo et al. (GCN 36498) in our images. Our non-detection upper limits are consistent with those reported by other teams (Lipunov et al., GCNs 36435, 36436; Niwano et al., GCN 36445; Mo et al., GCN 36452).

UT Start–End	Filter	Exposure (s)	Upper Limit
02:55:57–03:15:57	  R	1200	R_lim = 21.8
09:39:59–10:04:59	  V	1500	V_lim = 22.4
The field was calibrated against nearby SDSS stars, with magnitudes converted using Lupton (2005) equations, and has not been corrected for Galactic extinction.