GCN 43500: EP260119a: Assy AZT-20 optical observations

2026-01-22T12:09:42.174Z | rev 0 | event: GRB 260119A
A. Volnova (IKI), A. Pozanenko (IKI), M. Krugov (FAI), N. Pankov (IKI) report on behalf of IKI-GRB-FuN:

We observed the field of the EP260119a (Jiang et al., GCN 43447; GCN 43465; Cheng et al., GCN 43449) at the redshift of z ~ 5.47 (Corcoran et al., GCN 43469) with the AZT-20 telescope of Assy-Turgen observatory starting on 2026-01-20 (UT) 14:53 and taking several 60-second exposures in i' filter. 
In the stacked frame we detect the optical counterpart (Fortin et al., GCN 43450; GCN 43455; Eyles-Ferris et al., GCN 43452; Moskvitin and Spiridonova, GCN 43463; Liu et al., GCN 43464; Ma et al., GCN 43466; Zheng et al., GCN 43468; Corcoran et al., GCN 43469; Bochenek and Perley, GCN 43472; Pankov et al., GCNs 43476, 43499; Jin et al., GCN 43496). Preliminary photometry and observational details are the following:

Date           UT start  t-T0       Exp.    Filter Obj.   Err.   UL       Site/Telescope     
                        (mid,days)  (n*s)                       (3sigma)
2026-01-20     14:53:00  1.63500    63*60   i'     22.7   0.2    23.2     Assy-Turgen/AZT-20

The photometry is based on several nearby SDSS stars (i-magnitudes) and is not corrected for the Galactic extinction.