[vsnet-grb-info 6921] GRB 081109B: Swift/UVOT refined analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8511
SUBJECT: GRB 081109B: Swift/UVOT refined analysis
DATE:    08/11/10 11:20:01 GMT
FROM:    Paul Kuin at MSSL  <npkuin at googlemail.com>

N. P. M. Kuin (MSSL/UCL) and S. Immler (CRESST/GSFC/UMD) report on behalf
of the Swift UVOT team.

The Swift UltraViolet/Optical Telescope (UVOT) began observing GRB 081109B
(Swift BAT trigger number 334129; Immler et al., GCN Circ. 8502) on
November 9, 2008, at 13:50:24 UT, 187 seconds after the trigger.

No new source is detected in any of our images or summed images which
cover the BAT error circle descibed in GCN Circ. 8502.

The 5-sigma upper limits in the summed images for GRB081109B at a random
background position within the BAT error circle are given below:

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

wh     187       5946     560      >20.78 (5-sigma UL)
u      393      12195     533      >20.1  (5-sigma UL)
b      418       5741     235      >19.9  (5-sigma UL)
uvw2   468       6152     413      >19.8  (5-sigma UL)
v      492       6357     413      >19.3  (5-sigma UL)
uvm2   344      10975    1142      >20.2  (5-sigma UL)
uvw1   369      11882    1121      >20.5  (5-sigma UL)

The values quoted above are on the UVOT Photometric System (Poole et al,
2008, MNRAS 383, 627). They are not corrected for the expected galactic
reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).