{
  "bibcode": "2020GCN.29173....1G",
  "body": "Rahul Gupta (ARIES), Dimple (ARIES), Amit Kumar (ARIES), Vineet Ojha\n(ARIES), Ankur Ghosh (ARIES), Amar Aryan (ARIES),  Shashi B. Pandey\n(ARIES), and Kuntal Misra (ARIES) report:\n\nWe observed the optical afterglow ( Lipunov et al., GCN 29157; Gropp\net al., GCN 29158; Zhu et al., GCN 29159; Hu et al., GCN 29160;\nHosokawa et al., GCN 29164; Romanov et al., GCN 29165; Xin et al., GCN\n29166; Belkin et al., GCN 29167; and Kumar et al., GCN 29168) of Swift\nand Fermi detected GRB 201223A (Gropp et al., GCN 29158; and Wood et\nal., GCN 29161) using the 1.3m Devasthal Fast Optical Telescope (DFOT)\nand 1.04m Sampurnanand Telescope (ST) of Aryabhatta Research Institute\nof Observational Sciences (ARIES), India. The observations were\nstarted on 2020-12-23 at 19:01:46 UT. Multiple frames having an\nexposure time of 300 s were taken in the I filter using DFOT and in\nBVRI filters using ST. We clearly detected the optical counterpart at\nthe position reported by Gropp et al., GCN 29158.\n\n\nThe preliminary photometric estimate of the afterglow using I band\ndata of DFOT is the following :\n\n\nDate Start_UT           T_start-T0 (hrs)      Filter      Exp time (s)\n  Magnitude    Mag_err\n------------------------------ ------------------------------\n------------------------------ ------------------------------\n\n2020-12-23   19:07:55      1.158              I              300*1\n          18.71           0.04\n\n------------------------------ ------------------------------\n------------------------------ ------------------------------\n\n\nThe magnitude is not corrected for the Galactic and Host extinction in\nthe direction of the burst. Photometric calibration is performed using\nthe standard stars from the USNO-B1.0 catalogue.  Further processing\nof data is going on.\n\nThis circular may be cited.",
  "circularId": 29173,
  "createdOn": 1608829791000,
  "email": "rahulbhu.c157@gmail.com",
  "subject": "GRB 201223A: 1.3m DFOT and 1.04m ST optical observations",
  "submitter": "Rahul Gupta at ARIES, India  <rahulbhu.c157@gmail.com>",
  "eventId": "GRB 201223A"
}