GCN Circular 44398
Subject
EP260416a: Mondy optical observations
Event
Date
2026-04-23T12:39:12Z (5 months ago)
Edited On
2026-04-23T15:36:00Z (5 months ago)
From
Alina Volnova at IKI RAS <alinusss@gmail.com>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Alina Volnova at IKI RAS <alinusss@gmail.com>
Via
Web form
A. Volnova (IKI), A. Pozanenko (IKI), E. Klunko (ISTP), N. Pankov (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of the fast X-ray transient EP260416a (Hu et al., GCN 44307, 44324) at z = 1.909 (He et al., GCN 44336; An et al., GCN 44339) with the AZT-33IK 1.5m telescope of the Mondy observatory starting on 2026-04-21 (UT) 15:28:28 and taking several 120-seconds frames in the R band. The optical counterpart (Ducoin et al., GCN 44310; Li et al., GCN 44315; Hua et al., GCN 44318; Lee et al., GCN 44319; Zheng et al., GCN 44321; Martin-Carrillo et al., GCN 44328; Li et al., GCN 44334; He et al., GCN 44336; An et al., GCN 44339; Jelinek et al., GCN 44341; Guziy et al., GCN 44351; Ho et al., GCN 44354; Pawar et al., GCN 44373; Li et al., GCN 44376; Moskvitin et al., GCN 44395) is clearly detected in the stacked frame.
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)
2026-04-21 15:28:28 5.43677 27*120 R 22.72 0.09 23.3 Mondy/AZT-33IK
The photometry is based on nearby USNO-B1.0 stars (R2-magnitudes) and is not corrected for Galactic extinction.