TITLE:   GCN CIRCULAR
NUMBER:  36193
SUBJECT: GRB 240419A: Swift/UVOT Upper Limits
DATE:    24/04/20 10:46:38 GMT
FROM:    Sam Shilling at Lancaster University <shilling.sam@gmail.com>

S. P. R. Shilling (Lancaster U.), S. R. Oates (Lancaster U.), A. A. Breeveld (UCL-MSSL), M. De Pasquale (Univ. of Messina) and M. H. Siegel (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240419A
113 s after the BAT trigger (Siegel et al., GCN Circ. 36169).
No optical afterglow consistent with the enhanced XRT position (Goad et al., GCN Circ. 36174) 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) exposures and subsequent exposures are:

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

white_FC           113          263          147         >20.7
u_FC               271          521          246         >20.0
white              113         1025          334         >21.3
v                  602         1075           58         >18.6
b                  527          721           39         >19.3
u                  271          869          285         >20.1
w1                 652          845           39         >18.2
m2                 627         1099           58         >18.3
w2                 578         1050           58         >18.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.070 in the direction of the burst
(Schlegel et al. 1998).