[vsnet-grb-info 13779] GRB 130812A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15093
SUBJECT: GRB 130812A: Swift/UVOT Upper Limits
DATE:    13/08/13 16:15:52 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and V. D'Elia (ASDC) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 130812A 
139 s after the BAT trigger (D'Elia et al., GCN Circ. 15088).
No optical afterglow consistent with the XRT position (Evans et al. GCN 
Circ. 15089) 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

u_FC               139          389          246         >20.3
v                  445        12868         1191         >20.5
b                  394        11236         1459         >21.7
u                  139         7030          884         >20.8
w1                 494         6825          491         >20.5
m2                 469         6619          452         >20.3
w2                 421        12142         1376         >21.3

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.23 in the direction of the 
burst (Schlegel et al. 1998).