Researcher Information

SORAI Kazuo

Professor

Observational astronomy of galaxy evolution

Department of Physics, Nonlinear Physics

basic_photo_1
Theme

Observational studies of galaxy evolution from points of view of interstellar gas, star formation, and galactic structures. Joining the project of the Antarctic Terahertz Telescopes.

Fieldgalactic astronomy
Keywordgalaxy, interstellar gas, star formation, galaxy evolution, observational astronomy, Antarctic astronomy

Introduction of Research

I have investigated to make clear how galaxies have evolved from a viewpoint of interstellar gas and star formation through observations. Galaxies are assemblies of stars and interstellar medium, and the Milky Way is one of examples. The shape of galaxies is various, for example, there are spiral galaxies such as the Milky Way or the neighboring Andromeda galaxy, while there are galaxies whose shape is elliptical or irregular. Properties of galaxies located in dense regions are different from those of isolated galaxies. It is important to make clear how such variety results from, in order to understand galaxy formation and evolution. I have observationally investigated distributions, dynamics, physical properties of interstellar gas, which is material of stars, and relation among them and star formation activity in nearby galaxies. In recent years, I have engaged in a project that imaged many nearby galaxies in molecular gas tracer with the Nobeyama 45-m radio telescope, “CO multi-line imaging of nearby galaxies” (COMING). (see image “CO images of 147 nearby galaxies taken in COMING project”)

I have also engaged in development of telescopes and observational instruments. In recent years, I have joined a project to construct terahertz telescopes in the Antarctica, especially developing spectrometers and data reduction system.

study-image-0
CO images of 147 nearby galaxies taken in COMING project. White pseudo color represents that molecular gas is rich.

Representative Achievements

CO Multi-line Imaging of Nearby Galaxies (COMING) IV. Overview of the Project,
Sorai, K., Kuno, N., Muraoka, K., Miyamoto, Y., Kaneko, H., Nakanishi, H., Nakai, N., Yanagitani, K., Tanaka, T., Sato, Y., Salak, D., Umei, M., Morokuma-Matsui, K., Matsumoto, N., Ueno, S., Pan, H.-A., Noma, Y., Takeuchi, T.T., Yoda, M., Kuroda, M., Yasuda, A., Yajima, Y., Oi, N., Shibata, S., Seta, M., Watanabe, Y., Kita, S., Komatsuzaki, R., Kajikawa, A., Yashima, Y., Cooray, S., Baji, H., Segawa, Y., Tashiro, T., Takeda, M., Kishida, N., Hatakeyama, T., Tomiyasu, Y. Saita, C.,
Publications of the Astronomical Society of Japan, 2019, Vol.71, SP1, pp.S14:1-42
Properties of Molecular Gas in the Bar of Maffei 2,
Sorai, K., Kuno, N., Nishiyama, K., Watanabe, Y., Matsui, H., Habe, A., Hirota, A., Ishihara, Y., Nakai, N.,
Publications of the Astronomical Society of Japan, 2012, Vol.64, No.3, pp.51:1-10
Large-scale NH3 Observations toward the Galactic Star Forming Regions I. W 51 Molecular Clouds Complex,
Sorai, K., Habe, A., Nishitani, H., Hosaka, K., Watanabe, Y., Miwa, S., Ohishi, Y., Motogi, K., Minamidani, T., Awano, J., Sumida, S., Fukuya, Y., Uchida, R., Kaneko, N., Fujimoto, M. Y., Koyama, Y., Kimura, M., Nakai, N.,
Publications of the Astronomical Society of Japan, 2008, Vol.60, No.6, pp.1285–1296
Distribution and Kinematics of Molecular Gas in Barred Spiral Galaxies. II. NGC 253,
Sorai, K., Nakai, N., Kuno, N., Nishiyama, K., Hasegawa, T.,
Publications of the Astronomical Society of Japan, 2000, Vol.52, pp.785–802
Digital spectrometers for the Nobeyama 45-m telescope,
Sorai, K., Sunada, K., Okumura, S. K., Tetsuro, I., Tanaka, A., Natori, K., Onuki, H.,
Proc. SPIE Vol.4015, pp.86–95, Radio Telescopes, Harvey R. Butcher; Ed., 2000
Academic degreePh.D.
Self Introduction

I’m from Osaka.

Academic backgroundBachelor of Science, Kyoto University, 1993
Master of Science in Astronomy, The University of Tokyo, 1995
Ph.D. in Astronomy, The University of Tokyo, 1998
2021-Present Professor, Hokkaido University
Affiliated academic societyThe Astronomial Society of Japan, International Astronomical Union
ProjectNRO 45-m Telescope Legacy Program, "CO Multi-line Imaging of Nearby Galaxies" (COMING)
Room addressScience Building 2 2-316

Department of Physics, Nonlinear Physics

SORAI Kazuo

Professor

basic_photo_1
What is the research theme that you are currently focusing on?

I have been engaged in a study of the baryon cycles in galaxies. Galaxies including the Milky Way consist of many stars which form in cold gas. I have tried to make clear how gas gathers and how efficiently it transforms into stars. Some of the gas jets out from galaxies, hence, estimation of the amount of supply and consumption of the gas based on observations is very important for speculating galaxy evolution history. Although such work may be slightly quieter than great discovery, it suits me.
basic_photo_1
What do you usually do when your research work gets stuck?

I continue to think the issue because I think getting stuck means insufficiency of my thinking (serving instant coffee or shouting “Why I cannot find a way?” in the short run). I think and think the issue on the way to work or for waiting a train, and so on, because I have never interest in using smartphone. I’m weak at changing my way of thinking, though. When I was a graduate student or a postdoctoral, I experienced getting inspiration a few times in taking a shower. However, I truly regret that I have had no experienced again. Then I don’t expect such a way now.
basic_photo_1
Please tell us about yourself; things you are good at, your favorites, hobbies, and daily routines.

I have no hobbies confidently because I’m not entirely absorbed in anything. However, I like watching ski jumping. I have been fascinated since I watched the Olympic Games on TV in junior high school. Feeling the wind by jumpers on the spot is very fantastic. I wish I had moved to Sapporo more than 20 years earlier and had jumped by myself. I’m sorry that I cannot go to watching games these days.

Profile

Visionary Scientists List

basic_photo_1

Belongs

Department of Physics, Nonlinear Physics

Physics, Experimental Physics

Graduate School of Science, Department of Cosmosciences

Faculty of Pure and Applied Sciences, University of Tsukuba (cross-appointment), Tomonaga Center for the History of the Universe, University of Tsukuba (cross-appointment)