GCN Circular 32656
Subject
GRB 221009: Swift/UVOT Detection
Date
2022-10-10T12:41:35Z (3 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and S. Dichiara (PSU) report on behalf
of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of
GRB 221009 179 s after the BAT trigger (Dichiara et al.,
GCN Circ. 32632, and 32633). This GRB was initially reported as being
a new bright hard X-ray transient and named SwiftJ1913.1+1946.
Further analysis shows this is a GRB (Kennea et al, GCN Circ.
32635, and 32651).
The preliminary UVOT position was reported in the Dichiara et al. GCN.
The GRB was also detected by Fermi (Veres et al. GCN Circ 32636;
Bissaldi et al. GCN Circ. 32637; Lesage etal. GCN Circ. 32642),
IPN (Svinkin et al., GCN Circ. 32641); Agile (Ursi et al. GCN
Circ 32650). A redshift of 0.151 has been reported by de Ugarte
Postigo et al. (GCN Circ. 32648), and optical detections were
reported also (MASTER: Lipunov et al., GCN Circ. 32634 and 32639;
Liverpool Telescope photometry and spectrum: Perley GCN Circ
32638; VVS: Broens, GCN Circ. 32640; BOOTES-2/TELMA: Hu et al., GCN
Circ. 32644; Mondy: Belkin et al. GCN Circ. 32645; MeerLICHT: de Wet et al.
GCN Circ. 32646; Nanshan/NEXT photometry and Xinglong-2.16m
spectroscopy Xu et al. GCN Circ. 32647; Al Khatim Observatory:
Odeh, GCN Circ. 32649; REM: Brivio et al. GCN Circ. 32652). Near IR
was reported for PRIME by Durbak et al. GCN Circ. 32654 and radio
AMI-LA: Bright et al. GCN Circ. 32653 and ATA:Farah et al. GCN Circ. 32655.
Pre-discovery limits from ZTF: Karambelkar et al. GCN Circ. 32643.
Preliminary detections and 3-sigma upper limits using the UVOT photometric
system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early
exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 179 329 147 16.68 +/- 0.03
v 668 688 20 15.55 +/- 0.10
b 593 613 20 17.05 +/- 0.11
u 337 587 246 17.68 +/- 0.06
w1 718 1293 58 >18.2
w2 817 1219 39 >19.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.563 in the direction of the burst
(Schlegel et al. 1998).