本論文之目的主要是測試星系中氣體分子的隨機運動如何影響恆星的形成活動。長久以來氣體雲的物理狀態例，如密度與溫度被認為會影響恆星的形成活動。此外，分子雲中區域性的運動與擾動有可能會施加潛在的壓力抵擋重力塌縮，而阻止或延遲了恆星形成。然而實際的氣體運動如何影響恆星形成依舊沒有被世人詳細了解。我們從阿塔卡瑪大型毫米與次毫米波陣列取得CO(J=1-0)的資料，同時使用從史匹哲太空望遠鏡的 3.6 與 8 微米中紅外線數據，來研究數個鄰近星系上氣體分子運動如何影響恆星形成活動。本論文加入了速度離散作為新增的參數而提出了一個修正後的凱尼特-施密特定律 (Kennicutt- Schmidt law)。本論文的結果顯示氣體雲中相對高的速度離散率會降低恆星形成率。;We examined the influence of the random velocity of molecular gas on star-formation activities in galaxies. It is believed the physical states of a molecular cloud, such as temperature and density, influence star-formation activities in the cloud. Additionally, local and turbulent motions of molecules in a cloud may exert substantial pressure against gravitational collapse and thus prevent or delay star formation in the cloud. Nevertheless, how the star-formation activities influenced by the gas motion is still not quite understood. We obtained 12CO(J=1-0) flux and velocity dispersion from the Atacama Large Millimeter/submillimeter Array and combined these data with 3.6 and 8 micron midinfrared data from the Spitzer Space Telescope to evaluate the effects of gas motion on star-formation activities in several nearby galaxies. In the end we derived a modified Kennicutt- Schmidt law with velocity dispersion as an additional parameter. Our results indicated that the velocity dispersion in molecular clouds has negative influence on star-formation activity.
