[vsnet-grb-info 20063] GRB 171123A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22158
SUBJECT: GRB 171123A: Swift/UVOT Upper Limits
DATE:    17/11/24 13:06:31 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15 at ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 171123A
94 s after the BAT trigger (Evans et al., GCN Circ. 22148).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 22150)
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            94          243          147         >20.9
u_FC               308          557          246         >20.5
white               94         2397          489         >21.0
v                  637         2447          214         >18.8
b                  563         2373          194         >19.7
uvw1             13669        18855         1209         >20.7
uvm2             12763        13663          886         >20.6
uvw2             23870        35081         1032         >21.1


The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).