Date : 5/30 (Wed) [15:00 - ] @F313
Speaker: Dr. Rhythm Shimakawa (Subaru Telescope)
Title : (1)MAHALO-Subaru Deep Cluster Survey: Diverse protoclusters of galaxies at the cosmic high noon, (2)Metals in the Universe: Subaru Ultra-Deep Spectroscopic (SUDS) survey with Prime Focus Spectrograph
Abstract: (1) There is a great diversity of galaxy properties across this large-scale structure; outskirt galaxies tend to be late types like the Milky Way, while massive early-type galaxies dominate the centers of galaxy clusters just like Skyscrapers in the big city. To answer the question, "how did the Universe control formation of today's galaxies and create the diversity?", we are visiting histories of galaxies by observing distant Universe. This talk will present how massive cluster galaxies have been formed and quenched over the past 11 Gyr based on the deep H alpha and Ly alpha narrow-band imaging with the Subaru Telescope. We identify the evident Ly alpha depletion and active star formation in the fragmented group cores in a young protocluster at z=2.5 (Shimakawa, Kodama et al. 2017; 2018). Also, we find that more than half of massive forming galaxies in a protocluster at z=2.2 host AGNs, suggesting the importance of a role of AGNs in building early-type galaxies seen in the local clusters (Shimakawa, Koyama et al. submitted). (2) Nearly everything around us, including ourselves, is made of heavy elements like carbon, oxygen, iron, etc. We know that most of those came from massive stars. Stellar nucleosynthesis in massive stars can produce heavier elements, and then these elements have been ejected mainly by supernovae. However, we know little about how created metals have distributed across the Universe. Pursuing metals that stray in the Universe has been a great challenge even in the modern-day... Our SUDS project (Shimakawa, Prochaska et al.) will obtain 8k high-quality spectra of UV-luminous galaxies and quasars at z>1 over the COSMOS 1.3 square degree field, which for the first time enables metal absorption mapping beyond galaxies at 5-10 billion light-years away.

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