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GCN Circular 4411

Subject

GRB 051227: Swift/UVOT Upper Limits (Possible U-band

Date

2005-12-28T19:40:53Z (19 years ago)

From

Pete Roming at PSU <roming@astro.psu.edu>

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 4397Not found
 
 
) taken through each of the broadband filters. No 
source was detected at the XRT position (Beardmore et al. GCN 4402Not found
 
 
) or the 
R-band VLT position (Malesani, GCN 4404Not found
 
 
) 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.