{
  "bibcode": "2021GCN.31023....1K",
  "body": "[image: image.gif]Amit Kumar, Rahul Gupta, Amit Ror, Dimple, Ankur Ghosh, Arpan\nGhosh, Amar Aryan, Brajesh Kumar, S. B. Pandey, and Kuntal Misra (ARIES)\nreport:\n\n\nWe observed the Fermi GBM and LAT detected GRB 211023A (Fermi GBM\nTeam, GCN 30958; Lesage et al. 2021, GCN 30965; and N. Di Lalla et al.\n2021, GCN 30961) with 1.3m Devasthal Fast Optical Telescope (DFOT)\nlocated at Devasthal observatory of Aryabhatta Research Institute of\nObservational Sciences (ARIES), India. The observations were started\non 2021-10-28 at 19:22:54 UT, i.e., ~ 5.26 days after the Fermi\ntrigger. We have taken multiple frames having an exposure time of 300\nsec in the R filter. We clearly detected the optical afterglow of GRB\n211023A (Lipunov et al. 2021, GCN 30970; Zhirkov et al. 2021, GCN\n30977; Kann et al. 2021, GCN 30982; Hu et al. 2021, GCN 30990; Belkin\net al. 2021, GCN 31004, 31018, 31020; and Vinko et al. 2021, GCN\n31008) in our stacked image. The preliminary photometric estimate of\nthe afterglow is the following :\n\nDate Start UT   T-T0 (mid, days) Filter  Exp time (sec)   Magnitude\n\n=========================================================\n2021-10-28 19:22:54   ~5.28       R           300*15          21.37 +/- 0.08\n\n\nFurther observations are requested with 1.3m DFOT.The magnitude is not\ncorrected for the Galactic extinction in the direction of the burst.\nPhotometric calibration is performed using the standard stars from the\nUSNO-B1.0 catalog.\n\nThis circular may be cited.",
  "circularId": 31023,
  "createdOn": 1635578018000,
  "email": "rahulbhu.c157@gmail.com",
  "subject": "GRB 211023A: 1.3m DFOT Optical Observations",
  "submitter": "Rahul Gupta at ARIES, India  <rahulbhu.c157@gmail.com>",
  "eventId": "GRB 211023A"
}