GCN Circular 35004

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:

The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at GRB231111A 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 2023-11-11 14:18:02, 43 s after the BAT trigger. Observations were made under partially cloudy conditions. A new and changing source consistent with the XRT position (Osborne 2023, GCN 34991
Not found
 
 
) 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)  r'(mag)    i'(mag)      exposure_time (s)
----       -----    -----     -----            -----
69    16.6      16.3       16.0             52.5
133   16.8      16.3       16.4             75
208   17.1      16.7       16.7             75
283   17.2      16.8       16.8             75
358   17.3      16.9       16.8             75
433   17.5      17.2       17.0             75
508   17.6      17.3       17.2             75
583   17.6      17.4       17.3             75
658   17.7      17.5       17.3             75
733   18.0      17.7       17.3             75
808   17.9      17.7       17.6             75
883   18.1      17.9       17.6             75
958   18.0      17.8       17.7             75
1033  18.0      17.9       17.6             75
1108  18.2      18.0       17.6             75
1183  18.0      18.2       17.9             75
1296  18.4      18.3       18.0            150
1446  18.4      18.2       17.9             150



Uncertainties are estimated at ~ 0.1 mag for all three filters. tc-t0 = trigger time minus image center time. Calibration was done with 5 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.

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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.