TITLE:   GCN CIRCULAR
NUMBER:  16030
SUBJECT: GRB 140323A: Swift/UVOT Upper Limits
DATE:    14/03/23 19:47:02 GMT
FROM:    Massimiliano de Pasquale at MSSL-UCL  <m.depasquale@ucl.ac.uk>

M. De Pasquale (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140323A
106 s after the BAT trigger (Troja et al., GCN Circ. 16027).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 16028) 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           106          256          147         >20.4
u_FC               319          569          246         >19.5
white              106          793          186         >20.5
v                  649         5918          216         >19.1
b                  574        12334          773         >20.2
u                  319         6532          462         >19.9
w1                 698         6328          216         >19.5
m2                5923        16174          725         >20.4
w2                 798          818           19         >17.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.14 in the direction of the burst
(Schlegel et al. 1998).