[vsnet-grb-info 17455] GRB 160117B: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18881
SUBJECT: GRB 160117B: Swift/UVOT Detection
DATE:    16/01/17 21:23:02 GMT
FROM:    Lea Hagen at PSU  <lea.zernow.hagen at gmail.com>

L. M. Z. Hagen (PSU) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 160117B
64 s after the BAT trigger (Sonbas et al. GCN Circ. 18875). We detect
a fading source consistent with the XRT position  (Evans et al. GCN
Circ. 18880) and optical detections (Yurkov et al. GCN Circ. 18877,
Kruehler et al. GCN Circ. 18878).

The preliminary UVOT position is:
    RA  (J2000) =  08:48:46.76 = 132.19485 (deg.)
    Dec (J2000) = -16:22:00.1  = -16.36670 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).

Preliminary detections 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               63          213          147         18.24+-0.06
white              876         1025          147         18.26+-0.06
white             5700         5899          196         19.22+-0.09
white             7136         7335          196         19.48+-0.11
v                 6111         6311          196        >19.27
b                 5495         5695          196         19.84+-0.26
b                 6931         7131          196        >20.22
u                  275          525          245         17.84+-0.08
u                 5290         5489          196         19.13+-0.20
u                 6725         6925          196         19.14+-0.21
w1                5085         5285          196         18.75+-0.19
w1                6521         6721          196         18.90+-0.21
m2                6316         6515          196         19.22+-0.29
w2                5905         6105          196         19.18+-0.23
w2                7341         7533          188         19.50+-0.31

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).