[AAVSO-HEN] Swift/UVOT observations of GRB070805

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  6712
SUBJECT: Swift/UVOT observations of GRB070805
DATE:    07/08/06 12:06:28 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps at mssl.ucl.ac.uk>

P. Schady and A.M. Parsons (GSFC) report on behalf of the Swift UVOT team

The Swift/UVOT observed the field of GRB070805 (trigger=287088) starting 
33 minutes after the BAT trigger (Parsons et al. 2007, GCN Circ.6708). We 
do not find any new source in the UVOT observations within the BAT error 
circle or in the whole of the UVOT field of view, which we note is a very 
crowded field.

The 5-sigma upper limits in the co-added frames are listed below:

Filter   Tmid   Exposure   Magnitude
          (s)    (s)        (5-sigma UL)
white    3267   333         > 20.2
v        2825   274         > 18.5
b        3441   274         > 19.5
u        3287   274         > 19.2
uvw1     3133   274         > 19.0
uvm2     2979   274         > 18.8
uvw2     3384   452         > 19.4

where Tmid is the weighted mean team of the coadded exposure. The values 
quoted above are not corrected for the expected Galactic extinction 
corresponding to a reddening of E(B-V) = 0.202 mag in the direction of the 
burst (Schlegel et al. 1998).