{
  "bibcode": "2021GCN.29518....1G",
  "body": "Rahul Gupta,  A. Kumar, Dimple,  A. Ghosh, A. Aryan, B. Kumar, S. B.\nPandey, and K. Misra (ARIES) report:\n\nWe observed the field of INTEGRAL detected GRB 210208A (Mereghetti et\nal., GCN 29429) 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 2021-02-13 at 22:43:42 UT i.e. ~ 5.4 days after the INTEGRAL\ntrigger. We have taken multiple frames having an exposure time of 180\ns in the R filter. We did not detect any optical afterglow candidate\nin our single or stacked image within the INTEGRAL uncertainty circle\n(Mereghetti et al., GCN 29429). Our non-detection is consistent with\nHu et al., GCN 29439 and Kumar et al., GCN 29451.\n\n\nWe obtain the following 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======================================================\n2021-02-13 22:43:42   ~5.4          R   180*10      > 22.0\n\n\n\nThe magnitude is not corrected for the Galactic extinction in the\ndirection of the burst. Photometric calibration is performed using the\nstandard stars from the USNO-B1.0 catalogue.\n\nThis circular may be cited.",
  "circularId": 29518,
  "createdOn": 1613589979000,
  "email": "rahulbhu.c157@gmail.com",
  "subject": "GRB 210208A: 1.3m DFOT Optical upper limit",
  "submitter": "Rahul Gupta at ARIES, India  <rahulbhu.c157@gmail.com>",
  "eventId": "GRB 210208A"
}