TITLE:   GCN CIRCULAR
NUMBER:  37786
SUBJECT: GRB 241009A: LCO optical upper limits
DATE:    24/10/14 16:05:12 GMT
FROM:    Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>

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

We observed the field of GRB 241009A detected by SVOM/ECLAIRs (Dagoneau et al., GCN 37749) with the LCO 1m telescope at the Cerro Tololo Inter-American Observatory equipped with the Sinistro instrument. Our observation started at 2024-10-10 03:53:09 (T - TGRB = 8.6 h) with 4 x 180s exposure using the sdss-r filter.

We did not detect any uncatalogued optical source in the error region of SVOM/ECLAIRs (Dagoneau et al., GCN 37749) and at the position of the Swift/XRT afterglow source (Williams et al., GCN 37772). We derived the following upper limit (5 sigma, AB system) calibrated with the SkyMapper DR4 catalog and not corrected from the galactic extinction:

r > 20.9 (AB)

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