[vsnet-grb-info 20300] GRB 180205A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22396
SUBJECT: GRB 180205A: Swift/UVOT Detection
DATE:    18/02/06 12:58:32 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 180205A
182 s after the BAT trigger (Evans et al., GCN Circ. 22381).
A fading source consistent with the XRT position
(Page et al., GCN Circ. 22394),
also detected by (Zheng et al. GCN 22382;
Bolmer et al. GCN 22383; Tanvir et al. GCN 22384;
 Volnova et al. GCN 22387; Falcon et al. GCN 22390; Xin et al. 22392;
Zhu et al. GCN 22395)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  08:27:16.74 = 126.81975 (deg.)
    Dec (J2000) = +11:32:30.9  =  11.54191 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
for the first finding chart (FC) exposure and the early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag
white_FC           182          331          147         15.75 +/- 0.02
white              540          732           36         16.33 +/- 0.02
v                  158          612           52         16.11 +/- 0.09
b                  515          710           39         16.65 +/- 0.07
u                  490          686           39         16.82 +/- 0.07
uvw1               466          661           39         16.04 +/- 0.10
uvm2               441          636           39         16.32 +/- 0.15
uvw2               391          585           39         17.06 +/- 0.17

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).