{
  "bibcode": "2021GCN.31285....1K",
  "body": "T. Komesh (NU), B. Grossan (UCB, NU), Z. Maksut (NU), M. Krugov (FAI),�� \nE. Linder (UCB, NU), E. Abdikamalov (NU), G. F. Smoot (HKUST, UCB, NU), \nreport on behalf of the Energetic Cosmos Laboratory:\n\nThe Nazarbayev University Transient Telescope at Assy-Turgen \nAstrophysical Observatory (NUTTelA-TAO) observed the field of GRB \n211221A 19 s after receipt an automated GCN / BAT position alert, \nobserving in Sloan i' band, with the Burst Simultaneous Three-Channel \nImager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).\n\nWe started observations at 20:51:35 UT on 2021-12-21, 175 s after the \nBAT trigger. Observations were made in clear conditions starting at \nabout 30 deg. target altitude. No source consistent with the XRT (P. \nEvans et al., GCN Circ. 31275) was detected.�� We report the following \nresults:\n\nstart time������ t-t0(s)�� end time�������������� ULi'������������ exposure_time (s)\n------------������ --------�� ------------������������������ ------ --------------------\n20:51:35 ������ 175 �� 20:52:35 ���������������� 17.9 ������������������ 60\n20:52:50 ������ 257 �� 22:12:50 ���������������� 18.4 �������������� 150\n\nstart time is in UT. t-t0(s) gives the time since trigger, in seconds. \nUL i', gives the 5 sigma upper limit sensitivity in magnitudes, for \nimages co-added to the given exposure time. The first row in the table \ncorresponds to co-adds of an initial short exposure image sequence of \n7.5 s. The second row corresponds to co-adds from a continuing series of \n15 s exposures.�� Calibration was done with the 3 bright Pan-STARRS \ncatalog stars on our images.\n\nWe caution the reader that these are preliminary results, without color \nor other corrections. Please also note that times are approximate.\n----------------------------------\nNU = Nazarbayev University, Nur-Sultan, Kazakhstan\nUCB = University of California, Berkeley, USA\nHKUST = Hong Kong University of Science and Technology\nFAI = Fesenkov Astrophysical Institute, Kazakhstan\n\nThe NUTTelA-TAO Team acknowledges the support of the staff of the \nAssy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the \nFesenkov Astrophysical Institute, Almaty, Kazkhstan.",
  "circularId": 31285,
  "createdOn": 1640233057000,
  "email": "toktarkhan.komesh@nu.edu.kz",
  "subject": "GRB 211221A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)",
  "submitter": "Toktarkhan Komesh at Nazarbayev University  <toktarkhan.komesh@nu.edu.kz>",
  "eventId": "GRB 211221A"
}