GCN Circular 14095

R. Ruffini, L. Izzo, G.B. Pisani, C.L. Bianco, on behalf of a larger collaboration, report:

GRB 121217A, following our theoretical considerations based on the Induced
Gravitational Collapse scenario for GRBs-SNe, allows also for a different
solution with a cosmological redshift of z=0.8 (+- 0.1). We base this
result on a preliminary analysis of the superposition of the late X-ray
afterglow emission, considering GRB 090618 as the prototype of the class.
We have considered the first 75 ks of the X-ray afterglow light curve of
GRB 121217A in this preliminary analysis.
More details on the model will appear soon on the arXiv.

We also predict a presence of a SN emerging after about 18 (+- 3) days
from the GRB trigger, e.g. in the first days of January 2013.
Assuming an interstellar extinction obtained from the Schlegel et al.
(1998) extinction map and a supernova emission similar to the 1998bw one,
we estimate an observed magnitude of +24.5 (+- 0.5) in the J filter. We
further notice that, given the galactic latitude less than 5 deg (-4.89
deg), the calculated extinction value can differ at least of 1 mag.

Follow-up photometric and possibly spectroscopical observations are
strongly requested.