GCN Circular 9552
Subject
GRB 090621B: Swift/UVOT Upper Limits
Date
2009-06-22T13:45:39Z (15 years ago)
From
Peter Curran at MSSL <pac@mssl.ucl.ac.uk>
P.A. Curran (MSSL-UCL) reports on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090621B
76s after the BAT trigger (Curran et al., GCN 9545). No optical
afterglow consistent with the refined XRT position (Beardmore et al.,
GCN 9550) or the optical source observed by Levan et al. (GCN 9547) is
detected in the UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Poole et al. 2008, MNRAS, 383, 627) for the first exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
wh 76 18173 1221 >22.29
v 618 10774 1142 >20.67
b 544 23952 1986 >21.88
u 289 29731 2675 >21.77
uw1 668 29017 2882 >21.63
um2 643 28110 2006 >21.32
uw2 594 6589 432 >20.50
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.44 in the direction of the burst
(Schlegel et al. 1998).