TITLE:   GCN CIRCULAR
NUMBER:  38181
SUBJECT: GRB 241112B: LCO optical detection of the SVOM/VT candidate
DATE:    24/11/12 18:18:50 GMT
FROM:    Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>

D. Turpin (CEA/Irfu), A. Saccardi (CEA/Irfu, GEPI/Obs. de Paris), J. T. Palmerio (CEA/Irfu, GEPI/Obs. de Paris), S. Vergani (GEPI/Obs. de Paris), S. Basa (OSU Pytheas, LAM), E. LeFloc'h (CEA Paris-Saclay, DAp/AIM) on behalf of a larger collaboration.

We observed the field of GRB 241112B, detected by SVOM/ECLAIRs (Yang et al., GCN 38173) with the LCO 0.4m telescope at the Haleakala Observatory and the 1m telescope equipped with the Sinistro instrument at Siding Spring Observatory. Our observation started at 2024-11-12T11:41:20.771 (T - TGRB ~ 44min) with a series of 5x120s (sdssr, 0.4m), 4x180s (sdssi, 0.4m) and 5x120s (sdssr, 1.0m)  exposures.

At the position of the optical afterglow candidate reported by SVOM/VT (Qiu et al., GCN 38179), we detect a faint optical source at the detection limit of our single exposure frames which does not appear in the USNOB1.0 and SDSS DR12 catalogs. Note that the faint red extended source  present in the Legacy Survey DR10 catalog, mentioned by Qiu et al., GCN 38179, is about 3 arcsecond away from the position of the optical counterpart.

From our first exposure, we derive the following magnitude r = 19.0 +/- 0.3 (AB) at T-TGRB = 45 min (mid time).

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 101004719