GCN Circular 9469
Subject
GRB 090531B: Swift/UVOT Upper Limits
Date
2009-06-01T10:06:42Z (15 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL-UCL) and J. R. Cummings (NASA/UMBC) report on behalf of
the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 090531B starting 3924 s after the
BAT trigger (Cummings et al., GCN Circ. 9461), once the GRB came out of
Earth limb observing constraint. No optical afterglow is detected in any
of the UVOT exposures at the position of the X-ray afterglow (Sbarufatti
et al., GCN Circ. 9463), with the following three-sigma upper limits:
Filter T_mid(s) Exp(s) 3-sig Mag UL
white 3934 74 > 20.52
v 4105 98 > 19.08
b 4926 98 > 20.06
u 4721 98 > 19.74
uvw1 4515 98 > 19.65
uvm2 4310 98 > 19.32
uvw2 5336 98 > 19.61
The values quoted above are not corrected for the large Galactic
extinction due to the reddening of E(B-V)=1.12 in the direction of the
burst (Schlegel et al. 1998). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).