第31回LSTセミナーのご案内

• 日時：2026年6月25日（木）16:30–18:00

• 講師：Raffaele Raniさん (National Tsing Hua University, Taiwan)

• 接続先：[tennet:3834]をご参照ください

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CHIMPS2, CLOGS and MAJORS: A Multitracer Approach to Star Formation and Turbulence in the Inner and Outer Galaxy

Raffaele Rani (National Tsing Hua University, Taiwan)

Understanding how turbulence regulates the fragmentation of molecular clouds and shapes star formation remains a central challenge in Galactic astrophysics. Large JCMT surveys provide an opportunity to address these questions across a broad range of Galactic environments, from the dense molecular structures of the inner Milky Way to the outer Galaxy and active massive star-forming regions.

This talk presents an overview of three complementary JCMT programmes: the CO Heterodyne Inner Milky Way Plane Survey 2 (CHIMPS2), tracing molecular cloud populations in the inner Galaxy through 13CO(J=3→2) and 18O(J=3→2) emission; the CO Large Outer Galaxy Survey (CLOGS), mapping molecular gas in the outer Galaxy through 12CO(J=3→2) observations; and the MAssive JCMT Observed Regions of Star formation (MAJORS) survey, targeting dense gas associated with active massive star formation through HCN(J=3→2) and HCO+(J=3→2) observations. Together, these programmes probe molecular gas across a wide range of optical depths, density regimes, evolutionary stages, and Galactic environments.

Recent studies of turbulence in CHIMPS2 molecular clouds, based on a catalogue of over 5000 clouds and 17,000 associated dense substructures (dendrogram leaves) identified in 13CO(J=3→2) emission, apply the Brunt & Federrath statistical formalism to estimate the relative fractions of turbulent power contained in solenoidal and compressive motions (solenoidal fraction). These analyses provide observational constraints on the relative importance of different turbulent modes across a large molecular cloud population and, when combined with infrared tracers, enable estimates of star formation efficiency and evolutionary state. These results reveal an anti-correlation between solenoidal fraction and star formation efficiency, supporting previously identified connections between turbulence modes and star formation activity.

Ongoing observations from MAJORS and CLOGS will further enable these investigations by probing distinct density regimes and star-forming environments across the Milky Way. Together, these programmes offer new opportunities to compare turbulence, fragmentation, and star formation activity across a broad range of molecular gas conditions within a unified multitracer framework.

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LSTセミナーとは

将来の大型サブミリ波望遠鏡（LST/AtLAST）建設に向けて、サイエンス面でチャレンジしたいことや技術開発面で必要な研究を考える機会として、2021年12月から毎月1回の頻度で開催中のオンラインセミナーです。講演時間と質疑応答の目安は、それぞれ60分および30分です。また、セミナー終了後残っていただき、講演者の方とざっくばらんに意見交換することも可能です。

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コンタクト

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