TITLE:   GCN CIRCULAR
NUMBER:  39985
SUBJECT: GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
DATE:    25/03/31 19:48:32 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com>

N. Pankov (HSE, IKI),  A. Pozanenko (IKI), E. Klunko (ISTP),
R. Ya. Inasaridze (AbAO), A. S. Moskvitin (SAO RAS), O. I. Spiridonova (SAO
RAS), Yu. V. Sotnikova (SAO RAS), A. Ghosh (CAPP,
University of Johannesburg), S. Razzaque (CAPP, University of Johannesburg)
and IKI GRB-FuN report

We observed the field of GRB 250329A (Wang et al., GCN 39916;
Dichiara et al., GCN 39924) in the R filter with the 0.7-meter AS-32
telescope of the Abastumani Observatory (AbAO), in the R filter with the
1.5-meter AZT-33IK telescope of the Sayan Solar Observatory (Mondy) and in
the Rc filter with the 1-meter Zeiss-1000 of SAO RAS.

We do not detect the OT (Watson et al., GCN 39915; Wang et al.,
GCN 39917; Schneider et al., GCN 39918; Ghosh et al., GCN 39922; Ferro et
al., GCN 39927) down to the following limits.

Date UT start t-T0 Filter Exp. UL(3sigma) Telescope
(mid, d) (s)
2025-03-29 17:07:10 0.56824 R 98 x 60 21.7 AS-32
2025-03-29 19:11:57 0.64726 R 38 x 120 22.7 AZT-33IK
2025-03-29 20:00:02 0.66837 Rc 7 x 300 22.3 Zeiss-1000

Photometry is based on nearby USNO-B1.0 stars and is not corrected for
Galactic extinction
RA Dec R2
197.4269 9.4669 15.26
197.4732 9.4981 13.49
197.4408 9.5091 15.64