[vsnet-grb-info 16307] GRB 150314A: NOT further optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17588
SUBJECT: GRB 150314A: NOT further optical observations
DATE:    15/03/16 04:15:19 GMT
FROM:    Dong Xu at DARK/NBI  <dong.dark at gmail.com>

D. Xu (DARK/NBI), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), D.
Malesani (DARK/NBI), D. Slumstrup (NOT),  P. Jakobsson (U. Iceland)
report on behalf of a larger collaboration:

We continued to observe the field of GRB 150314A (Hagen et al., GCN
17573) using the 2.56m Nordic Optical Telescope (NOT) equipped with
the ALFOSC camera. We obtained 4x600 s R-band images with a median
time of 02:16:32 UT on 2015-03-16, i.e., 45.35 hr after the burst, and
in the seeing of 1.0"-1.5".

The optical afterglow (Zheng & Filippenko, GCN 17574; Trotter et al.,
GCN 17577) is still detected in our stacked image, with m(R) = 23.9
+/- 0.3 mag, calibrated with the same USNO B1 stars that were used in
our previous report (Xu et al., GCN 17582). Together with previous
observations (e.g., Perley & Cenko, GCN 17584; Zheng & Filippenko, GCN
17585), so far the object still nicely fits the decaying law of F(t) ~
t^-0.9.