GCN Circular 9397
Subject
GRB 090518: Swift/UVOT Upper Limits
Date
2009-05-19T11:50:39Z (15 years ago)
From
Frank Marshall at GSFC <marshall@milkyway.gsfc.nasa.gov>
F.E. Marshall (NASA/GSFC) and P. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 090518 starting 77 s after
the BAT trigger (Evans et al., GCN Circ. 9386). No optical afterglow
is detected in the initial UVOT exposures at the position
of the X-ray afterglow (Evans et al., GCN Circ. 9387).
Three-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) 77 227 147 >20.7
white 77 1367 373 >21.3
v 620 1417 97 >19.3
b 545 1341 78 >19.7
u 290 1316 304 >20.0
uvw1 669 1466 97 >19.7
uvm2 644 1442 97 >21.2
uvw2 596 1392 97 >20.0
The values quoted above are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).