GCN Circular 11816
Subject
GRB 110318B: Swift/UVOT Upper Limits
Date
2011-03-21T14:53:29Z (13 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <Stephen.T.Holland@nasa.gov>
S. T. Holland (CRESST/USRA/GSFC) and
R. Margutti (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT observed the field of GRB 110318B starting 58 s
after the BAT trigger (Margutti, et al., 2011, GCN Circ. 11799).
Settled observations started at 76 s. We do not detect an optical
afterglow at the UVOT-enhanced XRT position (Evans, et al., 2011, GCN
Circ. 11803) in any of the UVOT filters. Preliminary 3-sigma upper
limits for detecting a source in the finding charts and in the
co-added images, are
Filter T_start T_stop Exp(s) Mag
-----------------------------------------------
white (fc) 76 226 147 >21.5
868 1018 147 >21.5
v 619 7035 529 >20.6
b 545 7693 370 >21.2
u 289 7649 756 >21.2
uvw1 668 7445 529 >20.8
uvm2 5602 7239 393 >20.5
uvw2 1024 6829 236 >20.3
white 76 6623 626 >22.2
-----------------------------------------------
The quoted magnitudes and upper limits have not been corrected
for the expected Galactic extinction along the line of sight
corresponding to a reddening of E_{B-V} = 0.46 mag (Schlegel, et al.,
1998, ApJS, 500, 525).