GCN Circular 23020
Subject
GRB 180720B: ISON-Castelgrande optical observations
Event
Date
2018-07-22T23:39:09Z (7 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Schmalz (KIAM), F. Graziani (GAUSS). A. Pozanenko (IKI), A. Volnova
(IKI), E. Mazaeva (IKI), I. Molotov (KIAM) report on behalf of larger GRB
follow-up collaboration:
We observed the field of GRB 180720B (Swift-BAT detection: Siegel et al.,
GCN 22973, GCN 22975; Fermi-LAT detection: Bissaldi and Racusin, GCN 22980;
Fermi-GBM detection: Roberts et al., GCN 22981; MAXI/GSC detection: Negoro
et al., GCN 22993; Konus-Wind detection: Frederiks et al., GCN 23011)
with ORI-22 (22 cm) telescope of ISON-Castelgrande observatory starting on
July 20 (UT) 23:04:30. We obtained 150 images of 60 s exposure in Clear
filter. The optical afterglow (e.g. Martone et al. GCN 22976; Sasada et
al., GCN 22977; Reva et al., GCN 22979; Itoh et al., GCN 22983; Kann et
al., GCN 22985) is detected in separate images up to the end of series.
The coordinates of the optical afterglow are (J2000)
:02:06.792 -02:55:04:99 with uncertainties of about 0.5 arcsec in both
coordinates. Preliminary photometry of the afterglow at (UT, mid time)
23:22:21 is R =17.40 +/- 0.15. The photometry is based on nearby USNO-B1.0
(R2) stars.