Our laboratory aims to reveal galaxy evolution through observations and observational data.
If you have an interest in studying in this laboratory, please contact us.
NGC 3627 in radioNGC 3627 in infrared
What's New
last update: 24/11/18
24/9/11-13 Three members presented at ASJ autumn annual meeting 2024.
24/04/01 Two M1 students and a B4 student have joined our lab.
24/02/05 This year's master thesis best presentation award went to Kyoko Hama, a student in the lab.
24/02/02 Using the ALMA telescope, a research team led by the assistant professor Dragan Salak discovered strong evidence of suppression of star formation by a molecular gas outflow in a quasar-host galaxy when the Universe was less than one billion years old.Here is the press release site.
23/02/02 Two M2 students presented a master's thesis.
23/12/26 We spring cleaned our lab.
23/12/20-22 The intensive course "The structure of active galactic nuclei and its relation to their host galaxies" was held by Dr. Kishimoto (Kyoto Sangyo Univ.).
23/12/13-14 We held a workshop with Tsukuba Univ.
23/9/20-22 Two members presented at ASJ autumn annual meeting 2023.
23/9/1 A B4 student have joined our lab.
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23/8/19-26 A D1 student presented at URSI GASS 2023.
23/8/7-11 A D1 student presented at APRIM 2023.
23/4/1 A M1 student and a B4 student have joined our lab.
23/3/13-16 Two members presented at ASJ spring annual meeting 2023.
23/3/3 A B4 student presented a graduation thesis.
23/2/3 A M2 student presented a master's thesis.
22/12/27 Dr. Kazunori Akiyama (Massachusetts Institute of Technology), a graduate visited our lab.
22/12/27 We spring cleaned our lab.
22/12/15 Hitachi Daiichi high school students visited our lab.
22/12/5-7 The intensive course "Optical and infrared time-domain astronomy" was held by Dr. Sakoh (Tokyo Univ.).
22/11/25 Hokkaido Sapporo Nishi high school students visited our lab.
22/11/21-22 We held a workshop with Tsukuba univ.
22/9/15 A M2 student presented at ASJ autumn annual meeting 2022.
22/4/5 Two M1 students and a B4 student have joined our lab.
21/10/27-28 We held a workshop for telescopes operated by universities.
21/10/1 Dr. Dragan Salak has joined our lab.
研究紹介
銀河における星間物質と星生成活動に関する観測的研究
銀河の中で星はどのように生成されるのでしょうか？ 銀河の中で，どこでどのようにして星が生成されるのかということを明らかにするために，星が生まれるもとになる低温の分子ガスの分布，運動，性質をミリ波（電波）帯の分子の放射するスペクトル線の撮像観測から探っています．
棒渦巻銀河NGC 3627の低温ガス．(a) 水素原子の分布．(b) 一酸化炭素分子 (12CO) の分布．(c) 一酸化炭素分子の視線速度場．(d) 一酸化炭素分子の速度分散．(e) 一酸化炭素分子 (13CO) の分布．(This work made use of THINGS, ‘The HI Nearby Galaxy Survey’ (Walter et al. 2008). This publication made use of data from COMING, CO Multi-line Imaging of Nearby Galaxies, a legacy project of the Nobeyama 45-m radio telescope (Sorai et al. 2019).)
近傍銀河の大規模分子ガス撮像観測プロジェクトCOMING
銀河全体にわたる分子ガスの撮像観測は，可視光の写真などに比べるとはるかに少なく，銀河ごとの個体差と進化段階の違いなどを切り分けるのが難しいのが実情です．そこで，多数の銀河について電波写真を撮ることでこの切り分けをはっきりさせることを目指し，国立天文台野辺山宇宙電波観測所45 m電波望遠鏡の大学主導レガシープロジェクト「近傍銀河の分子ガスの大規模探査観測（CO Multi-line Imaging of Nearby Galaxies, COMING）」を国立天文台，筑波大学，大阪府立大学，鹿児島大学，関西学院大学，名古屋大学等と共同で実施しました．
赤外線衛星WISEで撮られた画像．(This image makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration.)
Galaxy Evolution from a Viewpoint of Star Formation
Observational investigation of interstellar medium and star formation activity in galaxies How do stars form in galaxies? We investigate distribution, dynamics, and properties of cold molecular gas from which stars form through imaging observations of molecular spectra in millimeter regime in order to make clear where and how stars form in galaxies.
(a) Distribution of atomic hydrogen. (b) Distribution of carbon monoxide (12CO). (c) Velocity field of the line of sight velocity of CO. (d) Velocity dispersion of CO. (e) Distribution of carbon monoxide (13CO). (This work made use of THINGS, ‘The HI Nearby Galaxy Survey’ (Walter et al. 2008). This publication made use of data from COMING, CO Multi-line Imaging of Nearby Galaxies, a legacy project of the Nobeyama 45-m radio telescope (Sorai et al. 2019).)
Imaging survey of molecular gas in nearby galaxies, COMING
Imaging observations of molecular gas covering the entire disk of galaxies are much less than optical images. The situation makes us difficult to divide evolutional stages of galaxies from those individual differences. We carried out a legacy project of the Nobeyama 45-m radio telescope, “CO Multi-line Imaging of Nearby Galaxies, COMING”, which is conducted by Hokkaido University, University of Tsukuba, Osaka Prefecture University, Kagoshima University, Kwansei Gakuin University, Nagoya University, Nobeyama Radio Observatory, and so on.
Why do galaxies show various shapes? We investigate factors of manifestations of various galaxies shapes using archival data such as those taken with an infrared satellite.
Images are taken with the infrared satellite WISE. (This image makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration.)
Development of observational instruments and systems in radio and optical astronomy
The Antarctic THz telescopes
Observations in submillimeter / THz wavelength are necessary to be done in sites where water vapour is as little as possible, i.e., cold district and little snowfall. The ultimate site where satisfies the condition on the ground is the inland area of Antarctica. Our team mainly consists of the University of Tsukuba and Kwansei Gakuin University has been promoting a plan to consult submillimeter/THz wavelength telescopes there. We put our experience in operation and improvement of the Tomakomai 11-m telescope (referring the next) to these Antarctic telescopes.
30-cm telescope
Tomakomai 11-m radio telescope (out of operation)
We had improved one of the geodesic VLBI (very long baseline interferometer) antenna to an astronomical radio telescope. The antenna was transferred from Communications Research Laboratory to Tomakomai Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University cooperating with the National Astronomical Observatory of Japan. We observed dense molecular gas in the Galactic star-forming regions in NH3 lines, monitored H2O maser emission in the Galactic massive star-forming regions, and searched active galactic nuclei in ultraluminous infrared galaxies. Although many students graduated from the Tomakomai telescope team, the observatory was closed because the telescope and observational instruments had been decrepit.
Probing physical conditions of molecular gas in nearby galaxies with CO multi-line excitation analyses
卒業論文
南極30 cmサブミリ波望遠鏡搭載用分光器の整備
2021年度
博士論文
Observational Studies on Physical Properties of Molecular Gas in Nearby Galaxies
修士論文
近傍渦巻銀河の棒状構造内部の分子ガスの性質と星生成効率
卒業論文
可視分光観測による近傍銀河の金属量測定
2020年度
修士論文
定量的分類による渦状腕の本数と銀河の大局的な性質の関係
Kpc-scale star formation in nearby galaxies based on relations among azimuthally averaged surface densities of star formation rate, stellar mass, and molecular gas mass
星生成効率を規定する要因に関する分子ガスの観測的研究
卒業論文
近傍銀河における12CO(J=1−0)と12μmの光度の関係
Physical Conditions of Molecular Gas in Nearby Galaxies Derived from CO Multi-line Excitation Analyses
2019年度
修士論文
銀河円盤部における高密度分子ガス存在比と星形成活動
卒業論文
近傍の星生成銀河における金属量勾配と色勾配
Student life
to enter our lab.
Assignment from undergraduate and graduate school
Assignment from undergraduate →After entering the faculty of Science, department of physics, assigned at the end of the 3rd year(basically 1 person/year)
Assignment from graduate school →Passed the space science major in the graduate school entrance examination(few/year)
E-mail address is added .hokudai.ac.jp at the end (_at_=@)
Kazuo Sorai
Professor
sorai_at_phys.sci
interstellar gas and star formation in galaxies, active galactic nuclei, interstellar gas in distant galaxies, development of radio/optical observational instruments and observation system
