TITLE:   GCN CIRCULAR
NUMBER:  24612
SUBJECT: GRB 190519A: Swift/UVOT Upper Limits
DATE:    19/05/20 13:56:20 GMT
FROM:    Jeffrey Gropp at PSU  <jdg44@psu.edu>

J. D. Gropp (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190519A
150 s after the BAT trigger (Ukwatta et al., GCN Circ. 24595).
No optical afterglow consistent with the enhanced XRT position
(Ukwatta et al. GCN Circ. 24597)
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               150          400          246         >18.9
v                  456         2571          272         >18.7
b                  406         2520          272         >19.7
u                  150         2495          646         >19.5
w1                 505         2610          262         >19.5
m2                 481         2595          272         >19.1
w2                 432         2546          272         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.42 in the direction of the burst
(Schlegel et al. 1998).