[vsnet-grb-info 4974] Swift/UVOT detection of GRB070714B

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6689
SUBJECT: Swift/UVOT detection of GRB070714B
DATE:    07/07/30 21:17:07 GMT
FROM:    Wayne Landsman at GSFC/SSAI  <landsman at milkyway.gsfc.nasa.gov>

W. Landsman (NASA/GSFC), F.E. Marshall (NASA/GSFC), and J. Racusin (PSU) 
report on behalf of the  Swift/UVOT team:

The Swift/UVOT observed the field of the short-hard burst GRB 070714B 
starting 70 s after the  BAT trigger (Racusin et al. GCN Circ. 
6620).     Upper limits on individual exposures were reported by 
Landsman & Racusin (GCN Circ. 6632).    We now  combine all data 
obtained within the first 7350s and find detections in the white (4.5 
sigma) and v (3.3  sigma) filters at the position of the source first 
reported by Melandri et al. (GCN Circ. 6621).     The source is detected 
in each of the three UV filters at the ~2.9 sigma level.   Presuming the 
detection in the UVW2 (2100 A) filter is real, an upper limit of ~1.3 
can be set on the redshift.


Filter    Tstart  Tstop     Exp       Mag
            (s)    (s)      (s) 
White       70    7143      628      20.95 ± 0.23

v          177    6117     1435      20.36 ± 0.32
          7355   87569     4321     >20.9 (3 sigma)

uvw1       607    6528      294      20.14 ± 0.38
         11649   99315     9741     >22.1 (3 sigma)

uvm2       583    6321      294      20.02 ± 0.37
         10742   98409     8750     >22.3 (3 sigma)

uvw2       687    7350      471      20.55 ± 0.37
         16463  104208     5313     >22.1 (3 sigma)