TITLE:   GCN CIRCULAR
NUMBER:  31628
SUBJECT: ZTF22aabjpxh/AT2022cva: Assy optical observations
DATE:    22/02/22 00:16:49 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed ZTF22aabjpxh/AT2022cva transient (Ho et al., GCN 31619) what 
is considered the likely afterglow of GRB 220219B (Ho et al., GCN 31619; 
Svinkin et al., GCN 31624) with AZT-20 telescope of Assy-Turgen 
observatory starting on 2022-02-21 (UT) 19:44:30.

We clearly detect the SDSS galaxy at photo_z = 0.248 (Ho et al., GCN 
31619). Due to non-optimal seeing (FWHM of about 2.4") we could not 
discriminate the afterglow source from the galaxy. We use aperture 
photometry and preliminary photometry (AB) of a source (afterglow+host 
galaxy) is following

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

2022-02-21 19:44:30  2459632.327  40*60   r'    19.20 0.03   22.1
2022-02-21 21:57:59  2459632.416  40*60   r'    19.45 0.02   22.7

The photometry is based on nearby PS1 stars
id		       r
J160337.10+311328.5    16.987
J160343.10+311452.9    18.700

The photometry of the the source is brighter than reported either in PS1 
or SDSS DR12, and source  is variable. We can conclude that the 
afterglow is detected and dominate over host galaxy brightness.