GCN Circular 31759
Subject
GRB 220306B: Swift/UVOT Upper Limits
Date
2022-03-15T13:10:24Z (2 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and Caputo (GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220306B
89 s after the BAT trigger (Caputo et al., GCN Circ. 31697).
No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 31700)
is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the
UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 89 239 147 >19.9
u_FC 302 552 246 >20.1
white 89 1716 402 >20.4
v 631 1601 117 >18.7
b 557 1701 117 >19.9
u 302 1676 343 >20.2
w1 680 1650 117 >19.3
m2 656 1626 117 >19.4
w2 607 5204 213 >19.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.578 in the direction of the burst
(Schlegel et al. 1998).