GCN Circular 30404
Subject
GRB 210706A: optical upper limit of Sintesz-Newton/CrAO and AS-32/AbAO
Date
2021-07-07T13:44:19Z (3 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (IKI, HSE), S. Nazarov (CrAO), R. Ya. Inasaridze (AbAO), A.
Pozanenko (IKI), S. Belkin (IKI, HSE) report on behalf of IKI GRB FuN:
We observed the filed of Swift/BAT-GUANO detection GRB 210706A
(Tohuvavohu et al., GCN 30393), GRB 210706A also triggered Konus-Wind
(Ridnaia et al., GCN 30403) with Sintesz-Newton 350mm f/5 telescope of
CrAO observatory and AS-32 telescope of Abastumani observatory (AbAO).
Observation started on 2021-07-06 (UT) 22:52:40 and consist of 6 images
of 300 s exposure in Clear filter (Sintesz-Newton) and in R-filter (UT)
2021-07-06 (UT) 20:23:40 (AS-32). In bothe telescopes we cover the whole
localization region of Swift/BAT-GUANO (Tohuvavohu et al., GCN 30393).
We find no new optical sources in either of the two XRT candidates
(https://www.swift.ac.uk/ToO_GRBs/00021455/). In particular no source
was detected in XRT afterglow candidate #2 (Tohuvavohu et al., GCN 30399).
Upper limit for of the stacked image is following
Date UT start t-T0 Filter Exp. OT err UL(3) Telescope
(mid, days) (s)
2021-07-06 20:23:40 0.50719 R 9*60 n/d n/d 20.5 AS-32
2021-07-06 22:52:40 0.60755 Clear 6*300 n/d n/d 21.5 Newton
The photometry is based on nearby USNO-B1.0 (R2) stars.
Our non-detections is consistent with results of GROWTH-India Telescope
(Kumar et al., GCN 30402).