[vsnet-grb-info 3910] GRB 061019: Swift/UVOT upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5735
SUBJECT: GRB 061019: Swift/UVOT upper limit
DATE:    06/10/19 20:59:38 GMT
FROM:    Frank Marshall at GSFC  <marshall at milkyway.gsfc.nasa.gov>

F.E. Marshall (NASA/GSFC) and C. Guidorzi (Univ Bicocca&INAF-OAB)
report on behalf of the Swift-UVOT team:

The Swift UVOT began observing the GRB 061019 field (trigger 234516) 2790
seconds after the BAT trigger (Guidorzi et al. GCN Circ. 5728). Exposures 
were taken with the V, B, U, W1, M2, and W2 filters. No new source was detected
within the XRT error circle (Guidorzi et al. GCN Circ. 5733). 
The effects of a nearby bright star complicate the analysis, but 
we estimate a 3-sigma upper limit of ~19th magnitude at the position 
of the optical afterglow (Covino et al. GCN Circ. 5730; Cobb et al. GCN Circ. 5734) 
for the initial exposure with the V filter.