TITLE:   GCN CIRCULAR
NUMBER:  31520
SUBJECT: GRB 220117A: Terskol and AbAO optical upper limits
DATE:    22/01/23 16:24:09 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), I. Sokolov (INASAN, KIAM),  I. Izvekova (Institute of 
Physics of NAS, ICAMBR of NAS), A. Shein (INASAN), Y. Markus (Institute 
of Physics of NAS, ICAMBR NAS), Y. Markelov (KIAM), R. Ya. Inasaridze 
(AbAO), N. Pankov (HSE),   G. Butenko (ICAMBR NAS), S. Belkin (IKI, 
HSE), A. Pozanenko (IKI) report on behalf of GRB IKI:

We observed the field of GRB 220117A (Melandri et al., GCN 31466) also 
detected by Fermi GBM Sub-Threshold (Veres, GCN 31487), and Konus-Wind 
(Frederiks et al. GCN 31511)  with Zeiss-2000, Zeiss-600  and K-800 
telescopes of Terskol observatory and with AS-32 telescope of Abastumani 
observatory. Within the enhanced XRT  Swift-XRT error circle (Beardmore 
et al., GCN 31472) we did not find any optical source. In particular we 
do not find the afterglow reported by Nanshan/NEXT (Fu et al., GCN 
31467), VLT (Palmerio et al., GCN 31480), LCO (Strausbaugh et al., GCN 
31481). Preliminary  upper limits are following

Date UT start t-T0 Filter Exp. OT Err UL(3sigma) Telescope

2022-01-17 18:32:01 0.12671 R     90*60  n/d   n/d   19.3 Zeiss-600
2022-01-17 19:41:36 0.16134 R     19*180 n/d   n/d   20.5 Zeiss-2000
2022-01-17 20:53:30 0.20545 R     35*60  n/d   n/d   19.4 AS-32

The photometry is based on the nearby PS1 stars.