GCN Circular 20965
Subject
GRB 170331A: Swift/UVOT Upper Limits
Event
Date
2017-03-31T23:34:37Z (9 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N. P. M. Kuin (UCL-MSSL) and A. Melandri (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field
of GRB 170331A 128 s after the BAT trigger (Melandri et
al., GCN Circ. 20946). No optical afterglow consistent
with the XRT position (Osborne et al. GCN Circ. 20960)
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 128 278 147 >20.4
u_FC 286 536 246 >19.6
white 128 1532 392 >21.0
v 616 1753 134 >18.5
b 542 1680 117 >19.1
u 286 1655 343 >19.7
w1 665 1631 117 >19.1
m2 1069 1606 58 >19.4
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).