GCN Circular 29559
Subject
GRB 210222B: Swift/UVOT Detection
Event
Date
2021-02-23T18:57:39Z (5 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210222B
101 s after the BAT trigger (Gropp et al., GCN Circ. 29545).
A source consistent with the XRT position (Gropp et al. GCN Circ. 29545)
is detected in the initial UVOT exposures. This source is also consistent
with previously reported optical detections (Hu et al., GCN Circ. 29546;
Strausbaugh, GCN Circ. 29547; Mong et al., GCN Circ. 29548; Parley, GCN Circ.
29549; Zhu et al., GCN Circ. 29551, Lipunov et al., GCN Circ. 29554). We note
that the lack of detection in the NUV passbands would be consistent with the
redshift of 2.198 reported by Agui Fernandez et al. (GCN Circ. 29552).
The preliminary UVOT position is:
RA (J2000) = 10:18:25.43 = 154.60595 (deg.)
Dec (J2000) = -14:55:55.1 = -14.93198 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
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 101 250 147 16.89 +/- 0.03
v 588 608 19 16.80 +/- 0.17
b 515 534 20 17.24 +/- 0.12
u 259 508 246 16.82 +/- 0.04
w1 639 1793 124 >18.8
m2 614 1606 78 >20.1
w2 564 1732 136 >19.1
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.102 in the direction of the burst
(Schlegel et al. 1998).