[vsnet-grb-info 19977] GRB 171027A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22064
SUBJECT: GRB 171027A: Swift/UVOT Upper Limits
DATE:    17/10/28 10:59:30 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (U. Warwick) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 171027A
96 s after the BAT trigger (D'Avanzo et al., GCN Circ. 22053).
No optical afterglow consistent with the optical position
(Watson et al. GCN Circ. 22057)
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            96          246          147         >20.6
u_FC               308          558          246         >20.0
white               96         6148          428         >21.2
v                  639         6558          432         >19.7
b                  564         5943          236         >20.3
u                  308         5737          462         >20.3
w1                 688         6835          282         >19.8
m2                5126         6763          393         >19.8
w2                4716         6354          393         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.14 in the direction of the burst
(Schlegel et al. 1998).