[vsnet-grb-info 16887] GRB 150819A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18168
SUBJECT: GRB 150819A: Swift/UVOT Upper Limits
DATE:    15/08/19 10:22:34 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld at ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150819A 
143 s after the BAT trigger (Ukwatta et al., GCN Circ. 18163).
No optical afterglow consistent with the XRT position (Evans et al. GCN 
Circ. 18167) 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           143          292          147         >21.0
u_FC               301          551          246         >20.2
white              143         7062          569         >21.4
v                  631         6037          274         >19.6
b                  557         6857          274         >20.3
u                  301         6652          501         >20.4
w1                 680         6447          274         >20.0
m2                 656         6242          274         >19.9
w2                 607         7135          346         >20.4

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.22 in the direction of the 
burst (Schlegel et al. 1998).