[vsnet-grb-info 20213] GRB 180103A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22309
SUBJECT: GRB 180103A: Swift/UVOT Upper Limits
DATE:    18/01/08 14:02:56 GMT
FROM:    Paul Kuin at MSSL  <npkuin at gmail.com>

N.P.M. Kuin (UCL-MSSL) and A..P. Beardmore (U. Leicester) report
on behalf of the Swift/UVOT team:

The Swift/UVOT performed observations of the field of GRB 180103A
(Beardmore et al. GCN Circ. 22305).  No optical afterglow consistent
with the XRT position (Melandri et al. GCN. Circ. 22308) is
detected in the UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) are:

Filter         T_start(ks)   T_stop(ks)      Exp(s)         Mag

v                  344.2       350.7         1044         >19.9
u                  344.2       350.7          848         >20.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.48 in the direction of the burst
(Schlegel et al. 1998).