GCN Circular 23239
Subject
GRB 180914B: Optical counterpart observation from OAJ
Event
Date
2018-09-16T08:58:16Z (7 years ago)
From
Antonio de Ugarte Postigo at IAA-CSIC <deugarte@iaa.es>
A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), L. Izzo (HETH/IAA-CSIC),
D.A. Kann (HETH/IAA-CSIC), C.C. Thoene (HETH/IAA-CSIC), H. Vazquez
Ramio (CEFCA), N. Maicas (CEFCA) and V. Tilve (CEFCA) report:
We have observed the field of GRB 180914B (Ursi et al., GCN 23226;
Verrecchia et al., GCN 23231; Bissaldi et al. GCN 23232; D���Ai et al., GCN 23236)
with the 0.8m T80 telescope of the Javalambre Astrophysical Observatory
(Teruel, Spain). The observation consisted of 12x300s i-band exposures, each
covering the complete LAT error box. The exposures started at 22:03:46 UT of
the 15th September, 27.68 hr after the burst. The counterpart identified by Zheng
& Filippenko (GCN 23237) and Troja et al. (GCN 23238) is well detected in the
individual images. Photometry of the first epoch, as compared with SDSS
reference stars yields i(AB)=18.84+/-0.03.
Comparing with the RATIR photometry (roja et al. GCN 23238), our photometry
implies a decay rate of alpha ~ -1.9 (where F_nu ~ t^alpha), indicating that the
afterglow has possibly entered a post-jet-break regime evolution.