Evolving Gas and Dust in the Galaxy and Galaxies to be seen by SPICA

¹ Department of Astronomy, Graduate School of Science, The University of Tokyo, Bunky-ku, Tokyo 113-0033, Japan
² Gradunate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
³ Okayama Astronomical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama, 719-0232, Japan

Abstract

Supernovae (SNe) and low-mass evolved stars eject elements synthesized in stellar interior to the interstellar space as solid particles, whereas dust grains are destroyed efficiently in SN shocks. A large fraction of interstellar dust must in fact be formed in dense clouds rather than being supplied by stellar sources. All of these processes in our Galaxy and nearby galaxies can be studied most effectively by imaging spectroscopy in the mid- to far-infrared instruments on board SPICA, only which allow us to investigate in detail the nature of dust grains as well as the abundance and physical conditions of gas species in the various regions in galaxies. This report summarizes the discussions of the science working group in Japan with the emphasis on investigations of the dust formation in stellar sources and dense clouds, and the material evolution in nearby galaxies that only SPICA can carry out.