(Proposal ID) S15A-079

(PI) Maeda, Keiichi

(Proposal Title)
 Environment around Supernovae through Time-Sequence HDS Observations

(Abstract)
We propose to investigate properties of circumstellar material (CSM) and 
interstellar material (ISM) of nearby galaxies beyond the local group, by high 
spectral resolution (< 10 km s^{-1}) and time-sequence observations of 
extragalactic supernovae (SNe). The proposal is complemented by our ongoing 
program S14B-141, to reach to the sample size of ~ 10 SNe with time-sequence, 
to publish the first statistic sample} as our goal. A SN serves as a bright 
backlight through which we can study properties and conditions of materials 
between the SN site and us, mostly arising from ISM, including atoms (e.g., 
Na, Ca), molecules (e.g., CH), enigmatic diffuse interstellar bands (DIB). 
We want to connect this information with properties of the galaxies (e.g., 
metallicity, age, star formation rate) and the SN types/properties, aiming 
at clarifying (1) the nature of extinction curves in galaxies and its relation 
to dust/ISM properties, and (2) the sites and carriers of DIBs. Our targets 
will include both SNe Ia and core-collapse (CC) SNe, enabling us to probe ISM 
in various environments. We will also search for signatures of CSM around SNe 
Ia as a direct probe to the yet-unresolved progenitor evolution.