(Proposal ID) S11A-064

(PI) Maeda, Keiichi

(Proposal Title)
A NIR View on Thermonuclear Ignition Process in Type Ia Supernovae

(Abstract)
We propose to take J & H band spectra and photometry for one or two nearby 
Type Ia Supernovae (SN Ia) at late phases such as ~ 150 - 200 days after the 
explosion. We expect to have a few SNe in one semester, which can be targets 
of ToO mode using IRCS and LGS-AO. Late-time spectra can be used to probe 
distributions of different elements/isotopes synthesized at the explosion, 
thus providing so far the only tool to tackle how the thermonuclear ignition 
starts. The investigation, however, has been mostly restricted to optical 
wavelength, where the bulk asymmetry can be derived using a few lines 
indicating the bulk offset in the explosion. NIR late-time spectroscopy is 
more challenging, but provides even more detailed information. In the 
wavelength range near [Fe II] J & H, there are virtually no contamination from 
other ions and other levels, allowing the detailed line profiles being 
investigated. This provides the distributions of stable Fe-peak elements and 
radioactive ^56Ni separately, and thus the detailed nature on ignition process 
and the hydrodynamic mixing. This will allow to investigate a relation between 
the detailed explosion mechanism and the standard-candle-natures of SNe Ia, 
with qualitatively different information from those previously obtained by 
conventional SN observations.