TITLE:   GCN CIRCULAR
NUMBER:  16019
SUBJECT: GRB 140320B: Swift/UVOT Upper Limits
DATE:    14/03/21 13:02:09 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (UCL-MSSL) and R. L. C. Starling, (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140320B
11975 s after the INTEGRAL trigger (Mereghetti et al., GCN Circ. 16004).
No optical afterglow consistent with the XRT position
(Pagani et al., GCN Circ. 16013) and the FTN optical position 
(Guidorzi et al., GCN Circ. 16003) 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            11975        29408         5864         >23.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).