title: An asymmetric energetic type Ic supernova viewed off-axis, and a link to gamma ray bursts.
abstract: Type Ic supernovae, the explosions after the core collapse of massive stars that have previously lost their hydrogen and helium envelopes, are particularly interesting because of their link with long-duration gamma ray bursts. Although indications exist that these explosions are aspherical, direct evidence has been missing. Late-time observations of supernova SN 2003jd, a luminous type Ic supernova, provide such evidence. Recent Subaru and Keck spectra reveal double-peaked profiles in the nebular lines of neutral oxygen and magnesium. These profiles are different from those of known type Ic supernovae, with or without a gamma ray burst, and they can be understood if SN 2003jd was an aspherical axisymmetric explosion viewed from near the equatorial plane. If SN 2003jd was associated with a gamma ray burst, we missed the burst because it was pointing away from us.
authors.affiliation: Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan. mazzali@ts.astro.it
authors.forename: Paolo A
authors.initials: PA
authors.lastname: Mazzali
authors.forename: Koji S
authors.initials: KS
authors.lastname: Kawabata
authors.forename: Keiichi
authors.initials: K
authors.lastname: Maeda
authors.forename: Ken'ichi
authors.initials: K
authors.lastname: Nomoto
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Filippenko
authors.forename: Enrico
authors.initials: E
authors.lastname: Ramirez-Ruiz
authors.forename: Stefano
authors.initials: S
authors.lastname: Benetti
authors.forename: Elena
authors.initials: E
authors.lastname: Pian
authors.forename: Jinsong
authors.initials: J
authors.lastname: Deng
authors.forename: Nozomu
authors.initials: N
authors.lastname: Tominaga
authors.forename: Youichi
authors.initials: Y
authors.lastname: Ohyama
authors.forename: Masanori
authors.initials: M
authors.lastname: Iye
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Foley
authors.forename: Thomas
authors.initials: T
authors.lastname: Matheson
authors.forename: Lifan
authors.initials: L
authors.lastname: Wang
authors.forename: Avishay
authors.initials: A
authors.lastname: Gal-Yam