[vsnet-grb-info 22990] GRB 190718A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25089
SUBJECT: GRB 190718A: Swift/UVOT Upper Limits
DATE:    19/07/18 16:18:19 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (U.Warwick) and V. D'Elia (SSDC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 190718A
70 s after the BAT trigger (D'Elia et al., GCN Circ. 25082).
No optical afterglow consistent with the XRT position
(Evans et al., GCN Circ. 25084) 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            70          219          147         >20.9
u_FC               282          532          246         >20.0
white               70         1184          353         >21.0
v                  612         1061           78         >18.3
b                  538         1159           58         >19.1
u                  282         4874          307         >20.0
w1                 661         4847          235         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).