{
  "submittedHow": "email",
  "bibcode": "2024GCN.35486....1G",
  "body": "Rahul Gupta, Amit K. Ror, Amar Aryan, and Shashi B. Pandey (ARIES) report\non behalf of a larger collaboration:\n\nWe performed the optical follow-up observations of the field of new year\nburst GRB 240101A detected by Swift (Cenko et al. 2024, GCN 35448),\nutilizing the 1.3m Devasthal Fast Optical Telescope (DFOT) situated at the\nDevasthal Observatory of the Aryabhatta Research Institute of Observational\nSciences (ARIES), India. Our observations started on 2024-01-01 at 15:37:15\nUT, approximately 1.28 hours post-detection. Multiple frames were captured in\nthe R filter with an exposure time of 300 seconds each. Subsequently, we\naligned and stacked the images. In our stacked image, no optical afterglow\nwas detected within the enhanced Swift-XRT error box (Beardmore et al.\n2024, GCN 35452), resulting in a preliminary 3-sigma upper limit of ~ 22.4\nmag. This non-detection is consistent with the observations of Zheng et al.\n2024, GCN 35453; Kuin et al. 2024, GCN 35457; and Volnova et al. 2024, GCN\n35460.\n\nAdditionally, we observed a potential signature of very faint optical\nemission at the position of the optical source reported by Volnova et al.\n2024, GCN 35460. The detected faint optical source (if related) may\npotentially represent a candidate afterglow or the associated host galaxy\nof GRB 240101A. Further deep follow-up observations using larger telescopes\nwill help to unveil the true nature of the optical source.\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",
  "circularId": 35486,
  "createdOn": 1704477694867,
  "subject": "GRB 240101A: 1.3m DFOT optical observations",
  "submitter": "Rahul Gupta at Aryabhatta Research Institute of Observational Sciences (ARIES) India <rahulbhu.c157@gmail.com>",
  "eventId": "GRB 240101A"
}