{
  "body": "Amit K. Ror, Ansika Gupta, Arjun Dawn, Shashi B. Pandey, Kuntal Mishra\n(ARIES) report:\n\n\nWe observed the field of GRB 241018A detected by SVOM (SVOM Team, GCN\n37812, 37819, 37826), with the 1.3m Devasthal Fast Optical Telescope\n(DFOT), located at the Devasthal Observatory of the Aryabhatta Research\nInstitute of Observational Sciences (ARIES), India. The observations were\nstarted on 2024-10-18 at 17:37:02 UT, i.e., ~ 0.24 days after the SVOM\ntrigger. We have taken multiple frames with an exposure time of 300 s in\nthe R filter. The observations were taken in the bright moon phase. We\nstacked the images after the alignment. We did not detect any optical\nafterglow (SVOM Team, GCN 37819) in our stacked image within the error box\nof the improved burst position by SVOM (SVOM Team, GCN 37826). We obtain\nthe following preliminary 3-sigma upper limit in the stacked image:\n\n\nDate Start_UT T_start-T0 (days) Filter  Exp time (s)  Limiting magnitude\n\n=========================================================\n\n2024-10-18 17:37:02     0.24     R     300s*12     > 20.9\n\n\nOur non-detection is consistent with Turpin et al. 2024, GCN 37818; SVOM\nTeam, GCN 37819; Malesani et al. 2024, GCN 37821; Ferro et al. 2024, GCN\n37822; Song et al. 2024, GCN 37824; Mohan et al. 2024, GCN 37825; Pankov et\nal. 2024, GCN 37827; Garcia et al. 2024, GCN 37828; and Liu et al. 2024,\nGCN 37830.\n\n\nThe magnitude is not corrected for the Galactic extinction in the direction\nof the burst. Photometric calibration is performed using the standard stars\nfrom the USNO-B1.0 catalog. This circular may be cited.\n",
  "eventId": "GRB 241018A",
  "submitter": "Amit Kumar Ror at ARIES <mitturor77894@gmail.com>",
  "createdOn": 1729589443323,
  "subject": "GRB 241018A: 1.3m DFOT Optical upper limit",
  "submittedHow": "email",
  "circularId": 37837,
  "bibcode": "2024GCN.37837....1R"
}