[vsnet-grb-info 14481] GRB 140206A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15795
SUBJECT: GRB 140206A: Swift/UVOT Detection
DATE:    14/02/06 18:20:25 GMT
FROM:    Samantha Oates at MSSL  <sro at mssl.ucl.ac.uk>

S. R. Oates (UCL-MSSL) and A. Y. Lien (NASA/GSFC/ORAU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 140206A
52 s after the BAT trigger (Lien et al., GCN Circ. 15784).
A source consistent with the XRT position (Osborne et al. GCN Circ. 15793)
and the optical positions reported by Oksanen et al. (GCN 15786) and 
Yurkov et al. (GCN 15788) is detected in the initial UVOT exposures. The 
lack of detections in the UV filters suggests a redshift ~2 - 3.

The preliminary UVOT position is:
  RA  (J2000) =  09:41:20.26 = 145.33442 (deg.)
  Dec (J2000) = +66:45:38.6  =  66.76072 (deg.)
with an estimated uncertainty of 0.50 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               52          202          147         15.88 +/- 0.02
v                  596          616           20         15.75 +/- 0.11
b                  522          542           20         16.51 +/- 0.09
u                  264          514          246         16.18 +/- 0.04
w1                 645        17944          963         >20.9
m2               16137        24450         1607         >21.2
w2               21898        22798          886         >21.0

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).