TITLE:   GCN CIRCULAR
NUMBER:  20268
SUBJECT: GRB 161214B: Swift/UVOT Afterglow Confirmation
DATE:    16/12/15 14:57:31 GMT
FROM:    Frank Marshall at GSFC  <femarsha@khamseen.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

Continuing Swift/UVOT observations of the field of GRB 161214B
(D'Avanzo et al., GCN Circ. 20257) show that the single source
consistent with the XRT position (Goad et al. GCN Circ. 20264)
reported by Marshall and D'Avanzo (GCN Circ. 20261) brightened
to 17.89 mag in white and then subsequently dimmed by more than
1 magnitude. This confirms the detection of the afterglow
reported by Kugel (GCN Circ. 20262), Klotz et al. (GCN Circ. 20263),
and Watson et al. (GCN Circ. 20266) following the suggestion
by Malesani et al. (GCN Circ. 20260). Detection of the afterglow
in the w2 filter indicates that the redshift is < 1.5.

Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are given in the following table. The magnitudes include contributions
from both the afterglow and the catalogued star SDSS J001524.26+072108.5. 

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag
white               84          234          147         19.3 +/- 0.1
white              748          768           18         17.9 +/- 0.1
white            27988        28895          841         19.5 +/- 0.1
u                  296          546          246         18.4 +/- 0.1
u                17963        18176          208         19.1 +/- 0.2
w2                5119         5319          197         18.8 +/- 0.2
w2               28903        29657          742         20.4 +/- 0.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.08 in the direction of the burst
(Schlegel et al. 1998).