{
  "submitter": "Toktarkhan Komesh at Nazarbayev University <toktarkhan.komesh@nu.edu.kz>",
  "createdOn": 1701856468692,
  "circularId": 35287,
  "submittedHow": "web",
  "body": "T. Komesh (NU), B. Grossan (UCB, NU), Zh. Maksut (NU), Zh. Abdullayev (NU), M. Krugov (FAI) and E. Abdikamalov (NU) report on behalf of the Energetic Cosmos Laboratory:\n\nThe Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) observed the field of GRB 231205B, 10 s after receipt an automated GCN / BAT position alert, observing in Sloan g', r' and i' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).\n\nWe started observations at 16:45:33 UT on 2023-12-05, 94 s after the BAT trigger. Observations were made in clear conditions. No source consistent with the XRT (J.P. Osborne et al., GCN Circ. 35275) was detected. We report the following results:\n\nstart time  t-t0(s)  end time    UL g'   UL r'  ULi'   exposure_time (s)\n-----------------------------------------------------------------------\n16:45:33     94     16:46:29     19.9     19.5    18.3          52.5\n16:46:43    164     16:49:13 \t 20.3     19.9    19.0          150\n\nstart time is in UT. t-t0(s) gives the time since trigger, in seconds. UL i', gives the 5 sigma upper limit sensitivity in magnitudes, for images co-added to the given exposure time. The first row in the table corresponds to co-adds of an initial short exposure image sequence of 0.5 s for g' and r' (these sub-second exposures are read-noise suppressed by our EMCCD cameras, with high gain electron multiplication active; other images are taken in conventional CCD operation mode), and 7.5 s for i'. The second row corresponds to co-adds from a continuing series of 3 s exposures for g' and r', and 15 s for i'.  Calibration was done with the 3 bright Pan-STARRS catalog stars on our images.\n\n----------------------------------\nNU = Nazarbayev University, Nur-Sultan, Kazakhstan\nUCB = University of California, Berkeley, USA\nFAI = Fesenkov Astrophysical Institute, Kazakhstan\n\nThis research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP14870504). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan.",
  "subject": "GRB 231205B: NUTTelA-TAO / BSTI Early Optical Limits",
  "eventId": "GRB 231205B",
  "bibcode": "2023GCN.35287....1K"
}