[vsnet-grb-info 18552] GRB 150302A: late-time imaging and optical afterglow confirmation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20000
SUBJECT: GRB 150302A: late-time imaging and optical afterglow confirmation
DATE:    16/10/06 06:03:14 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at dark-cosmology.dk>

D. Malesani (DARK NBI and DTU Space), J.P.U. Fynbo (DARK/NBI), and T. 
Kruehler (MPE), report on behalf of a larger collaboration:

We observed the field of GRB 150302A (Lien et al., GCN 17526) with the 
Nordic Optical Telescope (NOT) equipped with the ALFOSC imaging camera. 
Observations (4x300 s exposure) were carried out in the SDSS r filter, 
at a mean epoch 2016 Jun 23.94 UT (1.3 years after the GRB).

At the location of the optical afterglow candidate (Fynbo et al., GCN 
17527), we detect no source down to a limiting magnitude of r = 23.5, 
calibrated against nearby SDSS stars. By comparing with our early epoch, 
we conclude that the source has faded by more than 1 mag. Together with 
the positional consistency with the enhanced XRT location (Goad et al., 
GCN 17534), we can thus now confirm it as the optical afterglow of GRB 
150302A.

We acknowledge excellent support from the NOT observing staff, in 
particular John Telting.