[vsnet-grb-info 5484] GRB071227: Swift/UVOT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7150
SUBJECT: GRB071227: Swift/UVOT refined analysis
DATE:    07/12/28 04:00:24 GMT
FROM:    Antonino Cucchiara at PSU  <cucchiara at astro.psu.edu>

A. Cucchiara (PSU), T. Sakamoto (GSFC/UMBC)
report on behalf of the Swift-UVOT team:

The Swift/UVOT observed the field of GRB071227 (trigger #299787)
starting 86 seconds after the BAT trigger (Sakamoto et al.2007,
GCN Circ. 7147). We do not find any new source in any of the UVOT
single observations inside the XRT error circle.
Coadding all the images for each single filter an OT candidate
has been detected at 3-sigma confidence level in the White filter
coadded image at the position

RA: 03:52:31.102
DEC: -55:59:00.65

with an uncertainty of 0.6 arcsec (90% confidence).
This position is 4.5 arcsec from the XRT position.

The 3-sigma upper limits and the detection(in the UVOT photometric
system,Breeveld et al., GCN Circ. 6614)  are listed.

Filter       Tstart   Tstop     Exp      Magnitude  
              (s)      (s)      (s)   

White         86      6129       609      21.73 +- 0.36
v             68      6539       828      > 20.46
b            673      5923       409      > 21.01
u            648      5718       230      > 20.33
uvw1         624      5512       239      > 20.17
uvm2         599     10886      1191      > 21.00
uvw2         703      6334       419      > 20.65

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E_{B-V} = 0.01 mag in the
direction of the burst (Schlegel et al. 1998).