TITLE:   GCN CIRCULAR
NUMBER:  37040
SUBJECT: EP240801a: Continued optical observations at ZTSh (CraO)
DATE:    24/08/05 12:49:48 GMT
FROM:    Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com>

 N. Pankov (HSE, IKI), V. Rumyantsev (CrAO), A. Pozanenko (IKI) report on
behalf of GRB-IKI-FuN:

We observed the field of EP240801a (Zhou et al, GCN 36997) with ZTSh 2.6 m
telescope of CrAO. The observation were carried out in moderate conditions
with seeing about 2.0 arcsec. We taken series of images in the R-filter. We
clearly detect the optical counterpart (Fu et al, GCN 36998; Li et al, GCN
36999; Zheng et al, GCN 37000; Aryan et al, GCN 37002; An et al, GCN 37004;
Pérez-Fournon et al, GCN 37007; Malesani et al, GCN 37008; Zhu et al, GCN
37010; Moskvitin & Spiridonova, GCN 37012; Quirola-Vásquez et al, GCN
37013; Moretti et al, GCN 37014; Turpin et al, GCN 37015; Pankov et al, GCN
37016; Mo GCN 37017, ) in the stacked images. Preliminary
photometry is as follows:

Date UT start t-T0 Exp. Filter OT Err. UL
(mid, days) (s) (3sigma)
2024-08-02 20:41:58 1.493699 15*120 R 22.27 0.05 23.7
2024-08-03 19:43:38 2.456662 20*120 R 22.60 0.09 23.2

The magnitudes were calibrated using nearby stars from USNO-B1.0 catalog
(R2 magnitudes) and not corrected for the Galactic extinction.