{
  "bibcode": "2020GCN.27564....1K",
  "body": "TITLE:   GCN CIRCULAR\nNUMBER:  27563\nSUBJECT: GRB 200412B: Optical afterglow detection with 1.3m DFOT\nDATE:    20/04/13 09:05:41 GMT\nFROM:    Amit Kumar at ARIES, India  <amitkundu515@gmail.com,\namit@aries.res.in>\n\nA. Kumar (ARIES), A. Aryan (ARIES),  S. B. Pandey (ARIES), S. Mishra\n(ARIES), R. Gupta (ARIES), A. Ghosh (ARIES), Dimple (ARIES), and K. Misra\n(ARIES) report:\n\nWe observed the optical afterglow of the Fermi GBM detected GRB 200412B\n(GCN 27547, Lipunov et al., GCN 27555, GCN 27561)\nwith the 1.3m Devsthal Fast Optical Telescope (DFOT) at Aryabhatta Research\nInstitute of Observational Sciences (ARIES), Nainital\n(India),\nfrom 2020-04-12 UT 22:03:14 to 2020-04-12 UT 23:29:44 (corresponding to\n12.90 to 14.46 hours from the GRB trigger time). We observed a series of\n9x300s exposures in Bessel R filter and a series of 7x360s exposures in\nBessel I filter. We stacked the images and detected the optical afterglow\nof GRB 200412B in both Bessel R and I filters which is consistent with\noptical detections by Lipunov et al., GCN 27555, 27556.\n\nThe observed magnitudes are as follows:\n\nT_start-T0 (hours)   Start Date (UTC)             End Date\n(UTC)                  Filter            Magnitudes\n---------------------------------------------------------------------------------------------------------------\n12.90               2020-04-12 UT 22:03:14          2020-04-12 UT\n22:46:11          R               18.90 +- 0.03\n13.72               2020-04-12 UT 22:52:02          2020-04-12 UT\n23:29:44          I               17.54 +- 0.02\n\n\nPhotometry is done based on the USNO-B1.0 catalog. The quoted magnitudes\nare not corrected for Galactic extinction.",
  "circularId": 27564,
  "createdOn": 1586769258000,
  "email": "amitkundu515@gmail.com",
  "subject": "GRB 200412B: Optical afterglow detection with 1.3m DFOT",
  "submitter": "Amit Kumar at ARIES, India  <amitkundu515@gmail.com>",
  "eventId": "GRB 200412B"
}