GCN Circular 8973
Subject
GRB 090309: Swift/UVOT Upper Limits
Date
2009-03-10T22:03:58Z (15 years ago)
From
Wayne Landsman at GSFC/SSAI <wayne.b.landsman@nasa.gov>
W.B. Landsman (NASA/GSFC) and P. Evans (U. Leicester) report on behalf
of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 090309 starting 82 s after the
BAT trigger (Evans et al., GCN Circ. 8964). No optical afterglow is
detected in the initial UVOT exposures at the refined position of the
X-ray afterglow (Goad et al., GCN Circ. 8969). An r~19 field star (
GSC S9QR039837) is detected 3" from the XRT position. Three-sigma
upper limits using the UVOT photometric system (Poole et al. 2008,
MNRAS, 383, 627) in a 2" radius aperture for the first finding chart
(FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white (FC) 82 231 147 >21.0
white 82 6136 564 >21.8
v 624 17530 1317 >20.7
b 549 23995 1088 >21.4
u 294 23315 2241 >21.5
uvw1 673 22401 1998 >21.6
uvm2 648 18210 1875 >21.6
uvw2 599 16617 1318 >21.6
The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.23 in the direction of the burst
(Schlegel et al. 1998).