| Date: |
March 5, 2008, from 15:30 |
| Place: |
Room 633, 6th floor, Research Centers Building, Kashiwa Campus of the University of Tokyo. |
| Speaker: |
Keiichi Maeda (IPMU) |
| Title: |
Hunting for the Geometry of Supernova Explosions by Optical/NIR Observations |
| Abstract: |
In this talk, I will review basic physical processes (nucleosynthesis and radiation)
involved in interpreting optical/Near-Infrared (NIR) observations of supernovae.
Emphasis is placed on how to derive geometry of the innermost part of expanding
supernova materials -- a key ingredient to understand the still unresolved explosion
mechanism(s) of supernovae. For Type IIb/Ib/Ic supernovae (a class of core-collapse supernovae), we made a campaign to collect late-time spectra
(at about 1 year since the explosion) by the Subaru and VLT telescopes. We detected a variety of oxygen emission-line profiles, including a high
incidence
of double-peaked profiles, a distinct signature of an aspherical, bipolar explosion
viewed side ways. This suggests that most, if not all, of the supernovae in our
samples are aspherical. I will also discuss observations of Type Ia
supernovae (thermonuclear explosions of white-dwarfs) in NIR to derive their geometry. |
