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GCN Circular 31830

GRB 220403B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
2022-04-04T17:28:51Z (2 years ago)
Toktarkhan Komesh at Nazarbayev University <>
SUBJECT: GRB 220403B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)

B. Grossan (UCB, NU), T. Komesh (NU), Z. Maksut (NU), M. Krugov (FAI), E. Linder (UCB, NU), E. Abdikamalov (NU), K. Baigarin (NU), G. F. Smoot (HKUST, UCB, NU), report on behalf of the Energetic Cosmos Laboratory:

The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) observed the field of GRB 220403B 11 s after receipt an automated GCN / BAT position alert, observing in Sloan i' band, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).

We started observations at 20:43:09 UT on 2022-04-03, 27 s after the BAT trigger. Observations were made in partially cloudy conditions starting at about 43 deg. target altitude. No source consistent with the XRT (A.P. Beardmore et al., GCN Circ.31827) was detected.�� We report the following results:

start time����t-t0(s)�� end time�������������� ULi'������������ exposure_time (s)
---------�� ----��  ---------  ���������� ------     --------------------
20:43:09 ������ 27 �� 20:44:09 ���������������� 17.6 ������������������ 60
20:44:24 ������ 87 �� 20:46:54 ���������������� 18.4 ��������������   150

start 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 7.5 s. The second row corresponds to co-adds from a continuing series of 15 s exposures.�� Calibration was done with the 2 bright Pan-STARRS catalog stars on our images.

We caution the reader that these are preliminary results, without color or other corrections. Please also note that times are approximate.
NU = Nazarbayev University, Nur-Sultan, Kazakhstan
UCB = University of California, Berkeley, USA
HKUST = Hong Kong University of Science and Technology
FAI = Fesenkov Astrophysical Institute, Kazakhstan

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.
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