GCN Circular 10640
Subject
GRB 100420A: Swift/UVOT Upper Limits
Event
Date
2010-04-21T04:21:50Z (16 years ago)
From
Margaret Chester at PSU <chester@astro.psu.edu>
M. M. Chester (PSU) and W. H. Baumgartner (GSFC/UMBC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 100420A
134 s after the BAT trigger (Baumgartner et al., GCN Circ. 10628).
No optical afterglow consistent with the enhanced XRT position
(Beardmore
et al., GCN Circ. 10638) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first finding chart (FC)
exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 134 284 147 >20.8
u_FC 292 542 246 >20.0
white 134 13589 1503 >22.7
v 624 30201 1434 >20.5
b 548 19368 1911 >22.2
u 292 18659 2409 >21.7
w1 674 17744 1435 >21.6
m2 648 30928 1260 >21.5
w2 598 29287 1434 >21.4
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.11 in the direction of the burst
(Schlegel et al. 1998).