[vsnet-grb-info 18939] GRB 170111A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20441
SUBJECT: GRB 170111A: Swift/UVOT Upper Limits
DATE:    17/01/12 14:21:19 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel at swift.psu.edu>

M.H. Siegel (PSU) and A. P. Beardmore (U Leicester) 
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 170111A
111 s after the BAT trigger (Beardmore et al., GCN Circ. 20423).
No optical afterglow consistent with the XRT position
(Evans et al., GCN Circ. 20424)
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           111          261          147         >20.6
white              111          570          167         >20.7
v                  601          621           19         >18.0
b                  525          545           19         >19.6
u                  676          696           19         >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).