TITLE:   GCN CIRCULAR
NUMBER:  37838
SUBJECT: GRB241017A:  1.3m DFOT optical upper limit
DATE:    24/10/22 11:34:38 GMT
FROM:    ANSHIKA GUPTA at ARIES <anshika05180@gmail.com>

Anshika Gupta, Amit K. Ror, Arjun Dawn, Kuntal Mishra and Shashi B. Pandey (ARIES) report:


We observed the field of GRB 241017A detected by SVOM (SVOM Team, GCN 37799), with the 1.3m Devasthal Fast Optical Telescope (DFOT), located at the Devasthal Observatory of the Aryabhatta Research Institute of Observational Sciences (ARIES), India. The observations were started on 2024-10-18 at 15:57:20 UT, nearly 1.5 days after the SVOM trigger. We took multiple frames with an exposure time of 300 s in the R filter. We did not detect any optical afterglow in the stacked image within the error box of the burst position by the SVOM team (GCN 37799). We obtain the following preliminary 3-sigma upper limit in the stacked image:


Date Start_UT T_start-T0 (days) Filter  Exp time (s)  Limiting magnitude

================================================================ 

2024-10-18 15:57:20     ~1.5     R     300*12      > 22.0 


Our non-detection is consistent with Karambelkar et al. 2024 (GCN 37805); Mohan et al. 2024 (GCN 37808); Bochenek et al. 2024 (GCN 37810); and SVOM Team (GCN 37820).

The magnitude is not corrected for the Galactic extinction in the direction of the burst. Photometric calibration is performed using the standard stars from the USNO-B1.0 catalog. This circular may be cited.