GCN Circular 32218
Subject
GRB 220618A: Swift/UVOT Upper Limits
Event
Date
2022-06-18T15:40:50Z (3 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220618A
151 s after the BAT trigger (Troja et al., GCN Circ. 32214).
No optical afterglow consistent with the XRT position (Troja et al. GCN
Circ. 32214) 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 151 301 147 >19.8
u_FC 309 559 246 >18.9
white 151 609 167 >19.8
v 641 649 8 >17.4
b 565 585 19 >17.9
u 309 559 246 >18.9
w2 617 637 19 >18.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.391 in the direction of the burst
(Schlegel et al. 1998).