(Proposal ID) S14B-141

(PI) Maeda Keiichi

(Proposal Title)
 Probing Circumstellar and Interstellar Environments through Supernova Light

(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 (< 10km s^{-1}) and time-sequence observations of 
extragalactic supernovae (SNe). 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. With 3 nights within 
S14B, we aim to observe a total of ~10 SNe with temporal spectral sequence.
 We also propose a complementary set of ToO observations, 1 night in total 
within S14B (distributed in two or a few epochs), for intensive time-sequence 
follow-up of a few SNe.