GCN Circular 10400
Subject
GRB 091127: Detection of a Supernova
Date
2010-02-11T03:45:12Z (14 years ago)
From
Bethany Cobb at UC Berkeley <bcobb@astro.berkeley.edu>
B. E. Cobb, J. S. Bloom, S. B. Cenko, D. A. Perley (UC Berkeley) report on
behalf of a larger collaboration:
We have obtained multiple epochs of imaging of the field of GRB 091127
(Troja et al., GCN 10191) using the Gemini Multi-Object Spectrograph
(GMOS) on the 8 m Gemini South telescope and the ANDICAM instrument
on the 1.3m telescope at CTIO. For the first ~10 days post-burst, the
optical afterglow of the GRB (e.g. Smith et al., GCN 10192, Immler et al.,
GCN 10193, Cobb, GCN 10244) dominates the burst's optical emissions.
After 10 days post-burst, however, we find evidence of an additional
component of light which rises and then fades, and we consider this to be
due to an underlying SN related to this GRB.
The rise and decay characteristics of this GRB-SN are globally similar to
those of the prototypical GRB-SN, SN1998bw. The SN reaches peak
brightness at approximately 30 days post-burst, which is consistent with
the rise-time expected for a GRB-SN at redshift z=0.49 (Cucchiara et
al., GCN 10202 & Thoene et al., GCN 10233). The observed peak magnitude
of the SN (and any underlying contribution from a host galaxy) is I~21.7.
Correcting for a small amount of Galactic reddening (A_V=0.125) and
assuming little or no host-galaxy reddening (which is consistent with the
observations of the optical afterglow of the GRB), the absolute magnitude
of this GRB-SN is V~-20.5.
Observations and analysis of this GRB-SN are ongoing.