[vsnet-grb-info 17891] GRB 160424A: Swift/UVOT Upper Limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19337
SUBJECT: GRB 160424A: Swift/UVOT Upper Limit
DATE:    16/04/24 14:06:06 GMT
FROM:    Frank Marshall at GSFC  <femarsha at khamseen.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and A. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 3059 seconds after the BAT trigger (Lien et al. GCN Circ. 19335). 
No credible afterglow candidate
has been found in the initial data products. The 2.7'x2.7' sub-image 
covers 100% of the XRT error region (Evans et al. GCN Circ 19336).  
Sensitivity is less than usual because of reduced pointing stability.
We estimate an upper limit of 16th mag.
No correction has been made
for the expected extinction corresponding to E(B-V) of 0.03.