TITLE:   GCN CIRCULAR
NUMBER:  30851
SUBJECT: GRB 210919A: AbAO optical upper limit
DATE:    21/09/19 09:24:53 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE, IKI),  R. Ya. Inasaridze (AbAO), A. Pozanenko (IKI), S. 
Belkin (IKI), D. Datashvili (AbAO), V. R. Ayvazian (AbAO),  G. V. 
Kapanadze (AbAO)  report on behalf of GRB IKI FuN:

We observed  the field of Swift short GRB 210919A (Tohuvavohu et al. GCN 
30846)  with AS-32 telescope of Abastumani observatory (AbAO) in 
R-filter starting on Sep., 19 (UT) 00:48:33. We do not detect any object 
in the enhanced XRT position (Goad et al. GCN 30850). This is consistent 
with optical observations (Tohuvavohu et al. GCN 30846; Lipunov et al., 
GCN 30847; Hu et al. GCN 30848; Strausbaugh et al. GCN 30849).

Preliminary photometry of the field  is following

Date       UT start   t-T0    Filter Exp.    OT   Err.  UL(3sigma)
                        (mid, days)    (s)

2021-09-19 00:48:33   0.03194  R     52*60   n/d  n/d   22.1

The photometry is based on the nearby SDSS stars:
SDSS-DR12 R(Lupton)
5:21:01.5917 +1:18:14.862 17.82
5:20:58.8314 +1:18:59.733 18.36