GCN Circular 12584
Subject
GRB 111121A: Swift/UVOT Upper Limits
Event
Date
2011-11-22T14:39:55Z (14 years ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
N.P.M. Kuin, S. Oates (MSSL-UCL) and V. D'Elia (ASDC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 111121A
86 s after the BAT trigger (D'Elia et al., GCN Circ. 12578).
No optical afterglow consistent with the XRT position
(Evans et al, GCN Circ. 12579) is detected in the initial UVOT exposures.
The XRT enhanced position falls within the PSF wings of a B~13.6
magnitude star. Inspection of the event mode data after correction
for a slight wander in attitude shows no evidence for any transient
source.
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 dominated
by the nearly star and are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 86 235 147 >14.8
u_FC 298 548 246 >15.5
white 86 990 296 >14.7
v 629 822 39 >13.1
b 554 748 39 >14.2
u 298 723 265 >15.5
w1 678 873 39 >16.5
m2 653 847 39 >18.5
w2 604 797 39 >17.9
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.26 in the direction of the burst
(Schlegel et al. 1998).