GCN Circular 33114
Subject
GRB 221226B: Swift-UVOT Detection
Date
2022-12-27T17:23:08Z (a year ago)
From
Noel Klingler at NASA-GSFC / UMBC <njk5441@psu.edu>
N. Klingler (UMBC/NASA-GSFC/CRESST II) reports on behalf of the Swift/UVOT team:
The Swift-UVOT began settled observations of the field of GRB 221226B
76 s after the BAT trigger (Cenko et al., GCN Circ. 33108). A source
consistent with the XRT position (Goad et al., GCN Circ. 33109) and consistent
with the optical counterpart reported by VLT/X-shooter
(Xu et al., GCN Circ. 33110) is detected in the initial UVOT exposures.
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 76 226 147 20.54 +/- 0.22
v 4408 4608 197 >19.3
b 3793 3993 197 >20.0
u 288 5132 278 >20.1
w1 4818 5018 197 >20.0
m2 4613 4813 197 >19.5
w2 4204 4404 197 >20.0
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.017 in the direction of the burst
(Schlegel et al. 1998).