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東京大学・天文学教育研究センターでは2003年4月から談話会を開いています。
第一線で活躍されている研究者の方々を講師にお招きし、最先端の研究成果をお話しいただきます。
講師の方には、大学院生の参加者のことも考慮し、レビュー的な側面も含めた上で、ご自身の研究紹介をお願いしています。
なお、当談話会は天文学研究者・学生を対象に大学・大学院での
専門的な研究と教育を目的として開催されています。
一般の方は公開講座・講演会などにご参加いただければ幸いです。
ML: semiadm _at_ ioa.s.u-tokyo.ac.jp
please replace _at_ with @
Language: English
Abstract: The cosmic star-forming activity peaked at redshifts z=1-4 in the so-called "Cosmic Noon". This vigorous star production is driven by massive galaxies with star-formation rates (SFRs) 100-1000x higher than the Milky Way. However, it has long been unclear what causes these immense SFRs: are high-redshift galaxies forming stars very efficiently, or are they simply more gas-rich than present-day galaxies? Over the last decade, extensive surveys of molecular gas in high-z galaxies (via CO, dust, and [CII] emission) have established that they are indeed very gas-rich. However, a significant fraction of the molecular gas resides in diffuse, extended reservoirs, contributing little to the observed SFR. Maybe high-z galaxies have significantly enhanced star-forming efficiency after all? To answer this question, we need to study the dense gas from which stars form. As the low-J CO and [CII] emission trace gas down to densities of ~10^2 cm-3, we need to rely on emission lines of HCN, HCO+, and HNC. Unfortunately, as these lines are 10-100x fainter than CO or [CII], they have been detected in only a handful of high-z galaxies. I will showcase PRUSSIC: a comprehensive census of dense gas at high redshift with JVLA, ALMA - and a starring role by NOEMA. We find that high-z galaxies contain surprisingly little dense gas and have an enhanced star-forming efficiency. Moreover, we have obtained the first measurements of the HCN/HCO+/HNC ladders in high-z galaxies, allowing us to constrain the physical conditions (temperature, mechanical heating) of their dense-gas phase.
| # | Date | Speaker | Title | Chair |
| 424 | 2024年10月24日(木) 15:30-16:30 | Matus Rybak (Leiden University) | Monsters with empty bellies? A comprehensive census of dense gas in high-redshift, massive galaxies | I.Sakon |
| 425 | 2024年12月12日(木) 14:55-15:55 | Takashi Okamoto (Hokkaido University) | TBD | TBA |
| 426 | 2024年12月17日(火) 15:30-16:30 | Miguel Pereira Santaella (Instituto de Fisica Fundamental) | TBD | TBA |
| 427 | 2025年1月23日(木) 14:55-15:55 | Jeong-Eun Lee (Seoul National University) | TBD | 本郷談話会と共催 |
詳細はこちら: 令和6(2024)年度談話会
| # | Date | Speaker | Title | Chair |
| 423 | 2024年9月13日(金) 15:00-16:00 | Martijn Oei (Caltech) | Black hole jets on the scale of the Cosmic Web | TBA |
| 422 | 2024年8月5日(月) 15:30-16:30 | 郡和範 (国立天文台科学研究部) | ダークマター・ダークエネルギーの正体を暴く天文観測 | I.Sakon |
| 421 | 2024年7月3日(水) 15:30-16:30 | Farhad Yusef-Zadeh (Northwestern University) | Highlights of the MeerKAT Survey of the Galactic Center | I.Sakon/Y.Sofue |
| 420 | 2024年6月25日(火) 16:00-17:00 | James W. Beletic (Teledyne Scientific & Imaging) | The James Webb Space Telescope (JWST) - Humankind’s greatest space science facility | Imai/K.Motohara |
| 419 | 2024年6月25日火) 11:00-12:00 | Meghan Dorn (Teledyne Scientific & Imaging) | Teledyne Imaging Sensors Infrared FPAs for Astronomy & Earth Observation | I.Sakon/K.Motohara |
| 418(臨時) | 2024年6月19日(水) 14:00-14:30 | F. Peter Schloerb (Univ. of Massachusetts Amherst) | Thermal stabilization of the Large Millimeter Telescope | I.Sakon/K.Kohno |
| 417(臨時) | 2024年6月19日(水) 13:30-14:00 | David H. Hughes (Instituto Nacional de Astrofísica, Óptica y Electrónica) | The Large Millimeter Telescope (LMT) Alfonso Serrano: current status and future upgrades | I.Sakon/K.Kohno |
| 416 | 2024年6月13日(木) 15:30-16:30 | 服部公平 (統計数理研究所/国立天文台) | Dynamics and chemistry of the Milky Way revealed from Gaia data | I. Sakon |
| 415 | 2024年6月6日(木) 15:30-16:30 | Jong-Hak Woo (Seoul National University) | Understanding black hole engine based on time-domain studies | K. Morokuma |
| 414 | 2024年5月16日(木) 15:30-16:30 | Kana Morokuma (Institute of Astronomy, University of Tokyo) | Galaxy evolution in overdense environments | I. Sakon |
