GCN Circular 6683

A. Cucchiara (PSU), C. Guidorzi (U.Bicocca & INAF-OAB)
report on behalf of the Swift-UVOT team:

The Swift/UVOT observed the field of GRB070729 (trigger=286373)
starting 2007-0729 at 00:27:24, 91 s after the BAT trigger (Guidorzi et al.
2007, GCN Circ. 6678
Not found
 
 
). We do not find any new source in any of the UVOT
observations inside the refined XRT error circle (Guidorzi 2007, GCN Circ.
6782
Not found
 
 
).

The 3-sigma upper limits (in the UVOT photometric system,
Breeveld et al., GCN Circ. 6614
Not found
 
 
)for detecting a source inside the XRT error
circle in the first finding chart (FC) exposure and the co-added frames
(including the finding chart) are listed below:

Filter       Tstart   Tstop    Exposure    Magnitude
               (s)     (s)       (s)      (3-sigma UL)
White FC       91      191      99.7        20.27
White          91     6079       491        21.30
v             200    33740      1767        20.45
b            4241    19519      1163        20.97
u            4036    25507      2828        21.12
uvw1         3831    24911      3049        21.53
uvm2          606    27229      2764        21.34
uvw2         4652    28966      2164        21.46

The values quoted above are not corrected for the expected Galactic
extinction corresponding to a reddening of E_{B-V} = 0.02 mag in the
direction of the burst (Schlegel et al. 1998).