[vsnet-grb-info 17540] GRB 160131A Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18970
SUBJECT: GRB 160131A Swift/UVOT Detection
DATE:    16/02/01 18:09:05 GMT
FROM:    Marissa McCaule at PSU  <marissamc at swift.psu.edu>

L. M. McCauley (PSU), K. L. Page (U Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160131A
78 s after the BAT trigger (Page et al., GCN Circ. 18951).
A fading source consistent with the XRT position (Beardmore et al. GCN
Circ. 18159)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  05:12:40.33 =  78.16804 (deg.)
    Dec (J2000) = -07:02:58.81  =  -7.04967 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric
system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early
exposures are:

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

white_fc              78         228         147          13.77+-1.10
white               5051       11361        1081          16.71+-0.02
v                   4026        5662         393          15.72+-0.03
b                   4846       10449        1138          16.81+-0.02
u                    290         540         245          13.08+-0.03
u                   4641        6277         393          15.64+-0.03
uvw1                4436        6072         393          16.18+-0.04
uvm2                4231        5867         393          16.64+-0.06
uvw2                3821       12083        1098          17.43+-0.05




The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.11 in the direction of the burst
(Schlegel et al. 1998).