(Proposal ID) S13A-127 (PI) Maeda, Keiichi (Proposal Title) Census of Type Ia Supernova Populations through Late-Time Spectra (Abstract) We propose a follow-up program of nearby Type Ia Supernovae (SNe Ia) at late phases (> 150 days after the explosion). Studies in the past few years have uncovered diverse/multiple populations, and our goal is to understand how they are mutually related, and what are origins of these diversities. A proposal consists of two different observational setups but for the similar/same scientific goals. (1) FOCAS optical spectroscopy for ~ 10 SNe Ia (proposed here as non-ToO), and (2) IRCS/LGS-AO study of one or two most nearby SNe Ia in the late-phases (proposed here as ToO, since targets are rare although the time constraint is not important). The optical study aims at constructing a large sample (~ 40 SNe Ia, completed in S13A) to explore statistic natures in the explosion mechanism, progenitor, circumstellar (CSM) environment and extinction corrections. The NIR study aims at detailed study of individual objects, the insight we obtain here can provide a solid basis to interpreting the large optical data set. We want these two complementary setups approved in S13A, but it is also acceptable if only a part of the whole proposal is accepted.