TITLE:   GCN CIRCULAR
NUMBER:  16021
SUBJECT: GRB 140320C: Swift/UVOT Upper Limits
DATE:    14/03/21 13:05:13 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (UCL-MSSL) and J. K. Cannizzo (NASA/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140320C
19435 s after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 16007).
No optical afterglow consistent with the XRT position 
(Pagani et al., GCN Circ. 16015; 16017) 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 initial exposures are:

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

white            20211        32984         1056         >22.1
v                20986        33302         1087         >20.5
u                19435        37277         1741         >21.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).