[vsnet-grb-info 9297] GRB 100518A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10781
SUBJECT: GRB 100518A: Swift/UVOT Upper Limits
DATE:    10/05/19 11:00:50 GMT
FROM:    Peter Curran at MSSL  <pac at mssl.ucl.ac.uk>

P.A. Curran (MSSL-UCL)  and M. Stamatikos (OSU/NASA/GSFC) report on
behalf of the Swift/UVOT team:

During Swift target of opportunity observations of GRB 100518A 
(Stamatikos et al. GCN Circ. 10775),  Swift/UVOT began settled 
observations starting 9551 seconds after the INTEGRAL trigger 
(Mereghetti et al. GCN Circ. 10772). No optical afterglow consistent 
with the enhanced XRT position (Beardmore et al. GCN Circ. 10780) or the 
optical counterpart (Cano et al. GCN Circ. 10776) is  detected in the 
UVOT exposures. Preliminary 3-sigma upper limits using the UVOT 
photometric system (Poole et al. 2008, MNRAS, 383, 627) for the first 
finding chart (FC) exposure and subsequent exposures are:

Filter   T_start(s)   T_stop(s)   Exp(s)   Mag
------------------------------------------------
white    9551         9701        147      >21.4 (FC)
white    9551         11529       1033     >22.4
v        16324        17231       885      >20.7
b        9711         10618       885      >21.7
m2       17236        17899       652      >20.9
w2       11536        16318       1137     >21.6


The values quoted above are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).