TITLE: GCN CIRCULAR NUMBER: 33539 SUBJECT: GRB 230328B NUTTelA-TAO / BSTI Early Measurements DATE: 23/03/29 18:00:30 GMT FROM: Toktarkhan Komesh at Nazarbayev University toktarkhan.komesh@nu.edu.kz
T. Komesh (NU), Zh. Maksut (NU), B. Grossan (UCB, NU), Zh. Abdullayev (NU), M. Krugov (FAI), report on behalf of the Energetic Cosmos Laboratory:
The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at GRB230328B on receipt of 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).
We started observations at UT 2023-03-28 14:55:23, 41 s after the BAT trigger. Observations were made under clear conditions. A new and changing source consistent with the XRT position (Osborne 2023, GCN 33529) was detected. Note that these observations provide essentially full-time coverage, simultaneous in all three bands. We report the following photometric values for the OT:
tc-t0(s) g'(mag) exposure_time (s) -------- ------- -------- 68 17.1 54 125 17.1 60 185 17.5 60 245 17.6 60 305 18.0 60 365 18.0 60 440 18.6 90 530 18.8 90 620 19.1 90 725 19.1 120 845 19.8 120 965 17.7 120
tc-t0(s) r'(mag) i'(mag) exposure_time (s) ------ -------- ------ ------- 45 16.5 16.1 7.5 53 16.5 15.9 7.5 60 16.4 16.0 7.5 68 16.8 16.0 7.5 75 16.4 15.9 7.5 83 16.6 16.1 7.5 90 16.5 15.9 7.5 119 16.8 16.1 15 134 16.7 16.2 15 149 16.6 16.2 15 164 17.0 16.3 15 179 16.8 16.3 15 194 17.0 16.3 15 209 16.8 16.6 15 224 17.0 16.8 15 239 17.2 16.7 15 254 17.2 16.8 15 269 17.3 16.7 15 284 17.2 16.8 15 299 17.2 16.9 15 314 17.2 17.1 15 329 17.4 17.1 15 344 17.5 16.9 15 359 17.6 17.3 15 374 17.4 16.9 15 389 17.6 17.6 15 404 17.8 17.1 15 419 17.8 16.9 15 434 17.5 17.1 15 449 17.6 17.3 15 464 17.8 17.4 15 479 17.4 17.0 15 494 18.1 17.1 15 509 17.5 17.3 15 524 17.7 17.1 15 539 18.4 17.5 15 554 17.6 17.2 15 569 17.9 17.7 15 584 18.0 17.2 15 599 17.6 17.6 15 614 17.7 17.4 15 629 17.8 17.5 15 644 17.6 17.2 15 659 17.8 17.5 15 674 17.6 17.6 15 689 18.1 17.3 15 704 18.0 17.5 15 719 17.8 17.5 15 734 17.9 17.5 15 749 18.1 17.3 15 764 18.1 17.3 15 779 18.2 17.8 15 794 18.0 17.6 15 809 18.3 17.5 15 824 18.5 17.5 15 839 18.2 17.4 15 854 18.1 17.4 15 869 18.0 18.4 15 884 17.8 17.8 15 899 18.4 17.8 15 914 18.4 17.1 15 929 17.9 18.1 15 944 17.8 17.3 15 959 18.3 18.3 15 974 18.1 17.1 15 989 18.1 17.9 15 1004 18.3 17.6 15
Uncertainties are estimated at ~ 0.1 mag for all three filters except the latest images of g’ with indications of errors ~ 0.15 mag. tc-t0 = trigger time minus image center time. Calibration was done with 3-4 bright Pan-STARRS catalog stars on our images, and no other analysis or corrections.
We 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.
---------------------------------- NU = Nazarbayev University, Nur-Sultan, Kazakhstan UCB = University of California, Berkeley, USA FAI = Fesenkov Astrophysical Institute, Kazakhstan
This 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.