TITLE:   GCN CIRCULAR
NUMBER:  33240
SUBJECT: ZTF23aaarlti/AT2023avj: Assy continued optical observations
DATE:    23/01/31 17:15:27 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI), V. Kim (FAI, Pulkovo Observatory), A. Pozanenko 
(IKI), M. Krugov (FAI), S. Belkin (IKI) report on behalf of GRB IKI FuN:

We observed the  optical source ZTF23aaarlti/AT2023avj (Wang et al., GCN 
33226) with AZT-20 telescope of Assy-Turgen observatory starting on 
2023-01-28 (UT) 13:40:30.

We clearly detect the optical source (Wang et al., GCN 33226; Pankov et 
al., GCN 33227) which is also detected in radio (Perley  et al., GCN 
33233) and in X-ray (Ho et al., GCN 33238).

Preliminary photometry of the optical afterglow in a stacked image is 
following

Date       UT start  MJD        Exp.  Filter   OT     Err.  UL(3sigma)
                    (mid, days)  (s)

2023-01-28 13:40:30  59972.5698 90*60 r'(AB)   23.10  0.15   24.1

The photometry is based on nearby PS1 stars.