【場所】国立天文台・三鷹 中央棟（北）1階 講義室
【発表者1】利川潤 (総研大 D1、指導教員：柏川伸成)
【タイトル】Search for high-redshift protoclusters by wide-field imaging
Galaxy clusters play an important role for the large-scale structure of the universe and galaxy evolution. Galaxy clusters are located in the densest peaks of dark matter, and galaxies lying inside galaxy clusters are generally more massive and older than those in low-density regions.
When and how were these distinct properties formed? One promising line of study is to investigate directly the primitive galaxy clusters, “protoclusters”, in the early universe. Especially, we focus on the start of cluster formation. However, only a few high-z protoclusters were found. Therefore, we are searching for new high-z protoclusters in the deep and wide field of Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) Deep fields, and found two protocluster candidates at z~6.
【発表者2】Pan Hsi-An (総研大 D1、指導教官：久野成夫)
【タイトル】Molecular gas and star formation properties of NGC 628
It is widely accepted that molecular gas is the dominant material of star formation.
Since H2 (molecular hydrogen) is not observable, the second abundant molecular 12CO has become a proxy of tracing molecular gas. However, 12CO is optically thick, which is able to trace the molecular gas at the surface of molecular cloud only.
Therefore the observation in optically thin line, such as 13CO is needed. We observe both 12CO and 13CO toward NGC 628 to constrain the ability of a optically thin line in determining the molecular gas properties and its relation with star formation. Both observation and data analysis are ongoing.