GCN Circular 33725
Subject
GRB 230420A: Mondy optical afterglow detection, TSHAO, CrAO optical upper limit
Date
2023-05-05T22:18:02Z (a year ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE), A. Pozanenko (IKI), E. Klunko (ISTP), I. Reva (FAPI), V. Rumyantsev (CrAO), S. Belkin (IKI) report on behalf of GRB IKI FuN:
We observed the field of Swift GRB 230420A (Klingler et al. GCN 33658) with AZT-33IK telescope of Mondy observatory in R-filter on 2023-04-20 starting (UT) 13:31:08, with Zeiss-1000 telescope of of Tien Shan Astronomical Observatory on 2023-04-20 starting (UT) 22:11:07, with Shajn 2.6m telescope of CrAO on 2023-04-22 and 2023-04-23. We detect the afterglow (Hu et al., GCN 33663; Fu et al., GCN 33665; Fausey et al., GCN 33671; O'Connor et al., GCN 33680) in Mondy observatory and obtained upper limits in TSHAO and CrAO observatories. The afterglow is detected at coordinates of (J2000) 10 44 11.53 +32 06 28.4 which are compatible with NOT estimated coordinates (Fu et al., GCN 33665) and are within Swift XRT enhanced position (Osborneet al. GCN 33661).
Preliminary photometry of stacked images is following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma) Observ.
(mid, days) (s)
2023-04-20 13:31:08 0.15424 30*120 R 22.0 0.1 22.8 Mondy
2023-04-20 16:49:25 0.28431 20*120 R 22.7 0.3 22.7 Mondy
2023-04-20 22:11:07 0.36494 31*120 R n/d n/d 22.1 TSHAO
2023-04-21 15:23:44 1.25189 27*120 R n/d n/d 22.5 Mondy
2023-04-22 18:33:32 2.52854 49*120 R n/d n/d 22.6 CrAO
2023-04-23 19:22:36 3.41915 60*120 R n/d n/d 23.1 CrAO
2023-04-22+2023-04-23 2.97385 109*120 R n/d n/d 23.5 CrAO
The photometry is based on nearby USNO-B1.0 R2 stars.