GCN Circular 36158
Subject
EP240416A: Terskol Zeiss-2000 optical upper limit
Date
2024-04-18T12:40:39Z (a month ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
Via
legacy email
S. Belkin (IKI), I. Sokolov (INASAN, KIAM), A. Pozanenko (IKI), N. Pankov (HSE) report on behalf of GRB IKI FuN:
We observed the EP240416A (Cheng et al., GCN 36138) with the Zeiss-2000 telescope of Terskol observatory in R-filter starting on on 2024-04-16 (UT) 21:21:18. We did not detect the optical counterpart (Chen et al., GCN 36139; An et al., GCN 36144) down to the limiting magnitude of R~21.9. Preliminary photometry of a stacked image is the following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s)
2024-04-16 21:21:18 0.79832 70x90 R n/d n/d 21.9
The photometry is based on nearby USNO-B1.0 stars.
USNO-B1.0
RA DEC R2
13:32:30.1848000 -13:36:51.350400 13.67
13:32:25.6521600 -13:39:02.671200 14.26
13:32:19.2355200 -13:39:27.943200 13.96