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GCN Circular 4411

GRB 051227: Swift/UVOT Upper Limits (Possible U-band
2005-12-28T19:40:53Z (18 years ago)
Pete Roming at PSU <>
P. Roming (PSU), L. Barbier (GSFC), M. Trippico (GSFC-SSAI), J. Nousek 
(PSU) on behalf of the Swift/UVOT team

We have created summed images from Swift UVOT exposures of GRB051227 
(Barbier et al., GCN 4397) taken through each of the broadband filters. No 
source was detected at the XRT position (Beardmore et al. GCN 4402) or the 
R-band VLT position (Malesani, GCN 4404) down to the
following 5-sigma upper limits (no correction has been made for the 
expected visual extinction of about 0.14 magnitudes):

   Filter    T_range(s)      Tot Exp(s)   5sigUL(mag)
   V           96-4092           496              19.0
   B           462-10250      617              20.2
   U           408-6370        502              19.6
   UVW1   354-5904        950              19.6
   UVM2    300-4996        950              19.7
   UVW2   571-3988        113              18.5
   White    516-565          100              19.2

We note that from the U-band summed image a source is detected by the Swift 
analysis tool, uvotsource, at the 4.0-sigma confidence coincident with the 
position reported by Malesani. The magnitude is 19.8+/-0.3.
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