GCN Circular 17739
Subject
GRB 150423A: Swift/UVOT Upper Limits
Event
Date
2015-04-23T21:00:00Z (11 years ago)
From
Frank Marshall at GSFC <femarsha@khamseen.gsfc.nasa.gov>
F.E. Marshall (NASA/GSFC) and C. Pagani (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 150423A
74 s after the BAT trigger (Pagani et al., GCN Circ. 17728).
No optical afterglow consistent with the optical position
(Source 1 in Varela et al. GCN Circ. 17732; Perley GCN Circ. 17733)
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) exposures and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 74 223 147 >20.8
u_FC 286 535 246 >20.2
white 74 6067 733 >21.5
v 615 6477 452 >20.9
b 541 5862 255 >20.9
u 286 6924 513 >20.8
w1 665 6887 452 >20.9
m2 5048 6682 393 >20.8
w2 591 6273 432 >21.6
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).