GCN Circular 31643
Subject
ZTF22aabjpxh/AT2022cva (GRB 220219B): Mondy optical observations
Date
2022-02-23T22:36:04Z (2 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI, HSE), A. Pozanenko (IKI), N. Pankov (HSE), E. Klunko
(ISTP) report on behalf of GRB IKI FuN:
We observed ZTF22aabjpxh/AT2022cva discovered by ZTF (Ho et al., GCN
31619) with AZT-33IK telescope of Mondy observatory on 2022-02-21 and
2022-02-22. ZTF22aabjpxh/AT2022cva was observed also in optic (Kim et
al., GCN 31628; Hu et al., GCN 31639) and in X-ray by NICER (Pasham et
al., GCN 31635). ZTF22aabjpxh/AT2022cva is considered the likely
afterglow of GRB 220219B (Ho et al., GCN 31619; Svinkin et al., GCN 31624).
We clearly detect the SDSS galaxy at z=0.293 (Fremling et al., GCN
31629). Due to non-optimal seeing we could not discriminate the
afterglow from the galaxy. We use aperture photometry and preliminary
photometry of a source (afterglow+host galaxy) is following
Date UT start JD Exp. Filter OT Err. UL(3sigma)
(mid, days) (s)
2022-02-21 19:30:32 2.43966 30*120 R 19.19 0.03 22.8
2022-02-22 19:31:06 3.43936 29*120 R 19.34 0.03 22.8
The photometry is based on nearby SDSS DR12 stars
id r R(Lupton) V(Lupton)
J160337.10+311328.5 16.987 16.79 17.19
J160343.10+311452.9 18.700 18.51 18.90
Assuming the host galaxy has R = 19.7 we subtract a host galaxy flux
from a flux of the source (afterglow+host galaxy) and estimated power
law index of a light curve of the afterglow as -1.2, which is typical
for a GRB afterglow.