GCN Circular 20683
Subject
GRB 170214A: NOT optical afterglow confirmation
Event
Date
2017-02-16T07:38:43Z (10 years ago)
From
Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst <malesani@dark-cosmology.dk>
Daniele Malesani (DARK/NBI), Jens-Kristian Krogager (IAP and DARK/NBI),
and Adarsh Ranjan (IAP), report on behalf of a larger collaboration:
We observed the candidate optical counterpart of GRB 170214A (Mailyan &
Meegan , GCN 20675; Racusin et al., GCN 20676; Beardmore et al., GCN
20679; Troja et al., GCN 20681) with the Nordic Optical Telescope (NOT),
equipped with the AlFOSC camera. Three observations by 300 s each were
taken in the SDSS r band, under a seeing of 0.7", starting on 2017 Feb
16.263 UT (38.90 hr after the Fermi/GBM trigger). We note that our
pointing only covers XRT source #1 from Beardmore et al. (GCN 20679).
Within the XRT error circle (Beardmore et al., GCN 20679), we detect a
single object at coordinates (0.5" error):
RA(J2000) = 17:05:21.90
Dec(J2000) = -01:53:15.7
We assume that this is the same object reported by Troja et al. (GCN
20681). Calibrating against nearby SDSS stars, we measure r = 22.45 +-
0.07 AB. The fading by more than 1 mag compared to the RATIR measurement
(Troja et al., GCN 20681), as well as the spatial association with an
X-ray source (Beardmore et al., GCN 20679), confirm this object to be
the optical afterglow of GRB 170214A.