[vsnet-grb-info 19713] GRB 170813A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21480
SUBJECT: GRB 170813A: Swift/UVOT Upper Limits
DATE:    17/08/14 18:32:51 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170813A
144 s after the BAT trigger (Page et al., GCN Circ. 21468).
No optical afterglow consistent with the enhanced XRT position
(Osborne et al. GCN Circ. 21469)
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           144          293          147         >20.1
u_FC               302          551          246         >19.8
white              144         6769          727         >21.4
v                  632        11867         1140         >19.3
b                  557         6564          432         >20.7
u                  302         6359          659         >20.4
w1                 682         6154          413         >19.9
m2                4314        12580         1090         >20.5
w2                5339        10954         1145         >20.4