{ "body": "T. Komesh (NU), Z. Abdullayev (NU), Z. Maksut (NU), B. Grossan (UCB, NU), D. Berdikhan (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) pointed at GRB 250101A on receipt of an automated GCN / BAT position alert, observing in Sloan g' and r' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).\n\nWe started observations at 13:24:00 UT on 2025-01-01, 70 s after the BAT trigger. Observations were made in partly cloudy conditions. A new and changing source consistent with the XRT position (M.R. Goad et al., GCN 38761) was detected. Note that these observations provide essentially full-time coverage, simultaneous in two bands. We report the following photometric values for the optical transient: \n\ntc-t0(s) g'(mag) err r'(mag) err exposure_time (s)\n--------------------------------------------------------------\n100 18.66 0.07 18.20 0.07 57\n166 17.64 0.12 17.24 0.12 15\n181 17.51 0.10 16.98 0.14 15\n196 17.11 0.09 16.87 0.12 15\n211 17.34 0.13 16.90 0.09 15\n226 17.37 0.12 16.77 0.12 15\n241 17.31 0.09 16.65 0.06 15\n256 17.30 0.11 16.79 0.06 15\n271 17.43 0.09 16.85 0.10 15\n286 17.37 0.11 16.89 0.08 15\n301 17.50 0.16 17.02 0.08 15\n316 17.68 0.20 17.01 0.08 15\n331 17.52 0.15 17.01 0.10 15\n346 17.67 0.11 17.08 0.09 15\n361 17.60 0.11 17.13 0.09 15\n376 17.62 0.15 16.95 0.13 15\n391 17.96 0.14 16.91 0.08 15\n406 17.61 0.15 17.39 0.13 15\n421 17.81 0.13 17.23 0.12 15\n436 17.46 0.13 17.41 0.12 15\n451 18.10 0.15 17.41 0.11 15\n466 17.78 0.17 17.30 0.11 15\n481 17.81 0.13 17.29 0.10 15\n496 17.70 0.15 17.36 0.15 15\n511 17.92 0.13 17.45 0.11 15\n526 17.68 0.12 17.46 0.12 15\n541 18.30 0.19 17.53 0.13 15\n556 17.86 0.18 17.34 0.13 15\n571 17.96 0.14 17.31 0.14 15\n586 17.66 0.16 17.43 0.11 15\n601 18.16 0.17 17.82 0.14 15\n616 17.90 0.15 17.72 0.16 15\n631 17.85 0.13 17.23 0.11 15\n653 18.12 0.12 17.58 0.10 30\n683 18.06 0.10 17.47 0.07 30\n713 18.05 0.10 17.54 0.09 30\n743 18.01 0.10 17.46 0.08 30\n864 18.20 0.05 17.54 0.04 60\n924 18.17 0.07 17.67 0.06 60\n984 18.21 0.06 17.67 0.04 60\n1044 18.26 0.06 17.77 0.04 60\n1104 18.37 0.07 17.81 0.05 60\n1164 18.33 0.06 17.81 0.05 60\n1224 18.46 0.07 17.82 0.05 60\n1284 18.48 0.07 17.91 0.05 60\n1344 18.56 0.07 17.84 0.05 60\n1404 18.43 0.06 18.04 0.05 60\n1464 18.43 0.07 18.15 0.06 60\n1524 18.63 0.07 18.12 0.06 60\n1584 18.66 0.08 18.19 0.07 60\n1644 18.73 0.08 18.26 0.07 60\n1704 18.70 0.08 18.18 0.06 60\n1764 18.66 0.08 18.23 0.06 60\n1824 18.81 0.08 18.38 0.08 60\n1884 18.82 0.08 18.39 0.07 60\n1944 19.01 0.10 18.27 0.07 60\n2004 18.83 0.10 18.43 0.08 60\n2064 18.87 0.09 18.33 0.07 60\n2124 18.75 0.08 18.34 0.07 60\n2184 18.99 0.10 18.46 0.08 60\n2244 18.97 0.10 18.49 0.08 60\n2304 18.90 0.09 18.48 0.09 60\n2364 19.21 0.12 18.45 0.08 60\n2424 19.01 0.10 18.43 0.07 60\n2484 18.95 0.10 18.64 0.09 60\n2544 19.10 0.10 18.64 0.09 60\n2604 18.98 0.10 18.77 0.10 60\n2664 19.12 0.11 18.76 0.10 60\n2724 18.93 0.10 18.78 0.10 60\n2784 19.23 0.12 18.85 0.11 60\n2844 19.18 0.12 18.78 0.11 60\n2904 19.43 0.15 18.59 0.09 60\n2964 19.15 0.12 18.92 0.12 60\n3024 19.23 0.13 18.72 0.11 60\n3084 19.19 0.13 18.65 0.11 60\n3144 19.30 0.15 18.87 0.13 60\n3204 19.18 0.13 19.07 0.16 60\n3294 19.42 0.13 18.86 0.10 120\n3414 19.38 0.13 18.70 0.09 120\n3534 19.41 0.08 19.05 0.14 120\n3654 19.38 0.15 18.96 0.14 120\n3774 19.37 0.17 19.00 0.16 120\n4166 19.65 0.11 18.89 0.08 360\n4526 19.82 0.19 19.17 0.13 360\n\ntc-t0 = trigger time minus image center time. Calibration was done with 5 bright Pan-STARRS catalog stars on our images. A light curve of the optical transient is presented in Figure 1: https://ecl.nu.edu.kz/research/observations/gamma-ray-bursts/grb250101a\n\nOur results are in agreement with those reported in previously published circulars (Li et al., GCN 38753; Mohan et al., GCN 38754; Wu et al., GCN 38758; Escudero-Coca et al., GCN 38769; Zhang et al., 38744).\n\nWe caution the reader that these are preliminary results, without color or other corrections, and will likely change in small measure. Please also note that times are approximate.\n\n\n----------------------------------\nNU = Nazarbayev University, Astana, 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. AP26103591). 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.\n", "format": "text/plain", "eventId": "GRB 250101A", "createdOn": 1735819487950, "bibcode": "2025GCN.38777....1K", "editedOn": 1736052749462, "circularId": 38777, "subject": "GRB 250101A NUTTelA-TAO / BSTI Early Measurements", "submittedHow": "web", "submitter": "Toktarkhan Komesh at Nazarbayev University ", "version": 2, "editedBy": "Vidushi Sharma at NASA GSFC/UMBC on behalf of Toktarkhan Komesh at Nazarbayev University " }