[vsnet-grb-info 20814] GRB 180705A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22912
SUBJECT: GRB 180705A: Swift/UVOT Upper Limits
DATE:    18/07/06 10:11:35 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. A. Breeveld (UCL-MSSL), S. W. K Emery (UCL-MSSL) and M. Stamatikos 
(OSU/NASA/GSFC) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180705A
3368 s after the BAT trigger (Stamatikos et al., GCN Circ. 22902).
No optical afterglow consistent with the enhanced XRT position (Goad et 
al. GCN Circ. 22906) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system 
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding 
chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC          3368         3485          115         >20.2
white             3368         5327          312         >20.8
v                 4103         5738          393         >18.9
b                 4923        11649          311         >20.5
u                 4718        11527         1082         >21.0
w1                4513        16889          483         >20.5
m2                4308        15205          647         >20.1
w2                5333         5533          197         >20.4

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.06 in the direction of the 
burst (Schlegel et al. 1998).