Asphericity in supernova explosions from late-time spectroscopy.
Core-collapse supernovae (CC-SNe) are the explosions that announce the death of massive stars. Some CC-SNe are linked to long-duration gamma-ray bursts (GRBs) and are highly aspherical. One important question is to what extent asphericity is common to all CC-SNe. Here we present late-time spectra for a number of CC-SNe from stripped-envelope stars and use them to explore any asphericity generated in the inner part of the exploding star, near the site of collapse. A range of oxygen emission-line profiles is observed, including a high incidence of double-peaked profiles, a distinct signature of an aspherical explosion. Our results suggest that all CC-SNe from stripped-envelope stars are aspherical explosions and that SNe accompanied by GRBs exhibit the highest degree of asphericity.
Maeda
Keiichi
K
Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, Kashiwa-no-ha 5-1-5, Kashiwa City, Chiba 277-8582, Japan. maeda@ea.c.u-tokyo.ac.jp
Kawabata
Koji
K
Mazzali
Paolo A
PA
Tanaka
Masaomi
M
Valenti
Stefano
S
Nomoto
Ken'ichi
K
Hattori
Takashi
T
Deng
Jinsong
J
Pian
Elena
E
Taubenberger
Stefan
S
Iye
Masanori
M
Matheson
Thomas
T
Filippenko
Alexei V
AV
Aoki
Kentaro
K
Kosugi
George
G
Ohyama
Youichi
Y
Sasaki
Toshiyuki
T
Takata
Tadafumi
T