[vsnet-grb-info 4986] GRB070802: Swift/UVOT upper limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6701
SUBJECT: GRB070802: Swift/UVOT upper limits
DATE:    07/08/02 19:10:36 GMT
FROM:    Patricia Schady at MSSL/Swift  <ps at mssl.ucl.ac.uk>

N.P.M. Kuin (MSSL) and S. Immler (GSFC)               
report on behalf of the Swift-UVOT team:

The Swift/UVOT observed the field of GRB070802 (trigger=286809) 
starting 2007-08-02 at 07:09:30, 125 s after the BAT trigger (Barthelmy 
et al. 2007, GCN Circ.6692). We do not find a new source in the UVOT 
observations at the location of the refined XRT position (Evans and 
Mangano, 2007, GCN Circ. 6697).


The 3-sigma upper limits (in the UVOT photometric system, Breeveld et 
al., GCN Circ. 6614) for detecting a source inside the XRT error circle 
in the co-added frames (including the settling exposure and finding 
charts) are listed below:

Filter		Tstart	Tstop	Exposure	Magnitude
		(s)		(s)		(s)		(3-sigma UL)
white	142		16875	589.9	>21.25
v		125		12514	773.2	>19.96
uvm2	654		4821	239.4	>19.84
uvw1	679		4969	182.3	>19.77
u		703		6307	219.6	>19.52
b		728		16681	1109.0	>21.27
uvw2	758		10893	1127.5	>21.16

The values quoted above are not corrected for the expected Galactic 
extinction corresponding to a reddening of E_{B-V} = 0.026 mag in the 
direction of the burst (Schlegel et al. 1998).