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#author("2026-04-15T01:39:59+00:00","default:wwwadm","wwwadm") #author("2026-05-11T00:18:24+00:00","default:wwwadm","wwwadm") * IoA Seminar 2026 / 令和8年度(2026年度) 東京大学天文学教育研究センター談話会 [#c9bc2851] #contents * 本談話会について [#c1b638ff] ** 趣旨 [#d48cd456] 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。&br; 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>https://www.u-tokyo.ac.jp/ja/society/visit-lectures/d04_01.html]]などにご参加いただければ幸いです。 **定例日時 [#ve668db6] - 木曜日 15:30-16:30 **場所 [#j9cedf34] - 天文センター講義室と zoom のハイブリッド開催を予定 **世話人（天文センター） [#q8bd3108] ML: semiadm _at_ ioa.s.u-tokyo.ac.jp please replace _at_ with @ - 2025年度 -- SAKON, Itsuki 左近 樹 isakon_at_ ioa.s.u-tokyo.ac.jp -- Kohno, Kotaro 河野孝太郎 kkohno_at_ioa.s.u-tokyo.ac.jp -- Kamizuka, Takafumi 上塚貴史 kamizuka_at_ioa.s.u-tokyo.ac.jp **天文学教室談話会について [#ecc2eb80] - 天文学教室談話会については、[[こちら>http://www.astron.s.u-tokyo.ac.jp/seminar/seminar/]]をご覧ください。 * Upcoming Seminars [#ebd6a62d] --------------------------------------------------------- ** No. 440 : Apr. 16, 2026 (Thu) 15:00-16:00 [#dad05fe7] *** Place: Room 1109, Department of Astronomy, University of Tokyo /Zoom (hybrid) [#va7fc746] *** Speaker: Joss Bland-Hawthorn (Director, Sydney Institute for Astronomy, U Sydney) [#d2a6b465] *** Title: The long-term evolution of turbulent discs in high-redshift galaxies [#kf065e92] ** No. 441 : May. 28, 2026 (Thu) 15:30-16:30 [#dad05fe7] *** Place: Lecture room, Institute of Astronomy, University of Tokyo /Zoom (hybrid) [#va7fc746] *** Speaker: James Jackson (NRAO, USA) [#d2a6b465] *** Title: [C II] and [O I] Absorption and Self-Absorption from the “Skins” of Clouds [#kf065e92] Language: 英語 (English) Abstract: Most disc galaxies go through an early epoch of being "gas rich," an era that is being actively explored today through ALMA and JWST observations. This high gas-fraction phase got going much sooner (z > 3) than anticipated by cosmological N-body simulations. A new class of controlled (Nexus) simulations of these early times reveals that these turbulent discs have extraordinary properties. Unexpectedly, m=2,3 spiral arms, stellar and gaseous bars, even X-shaped/peanut bulges, all form under these conditions. The high gas content accelerates stellar migration and stabilizes the disc against buckling. Moreover, baryon sloshing driven by strong feedback gives rise to thick stellar discs, a likely origin of alpha-enriched thick stellar discs observed today. The sloshing gives rise to specific signatures that may already be observable in ALMA data. We discuss the implications of the new work on galaxy studies. At high spectral resolution, the [C II] 158 mm and [O I] 63 mm lines exhibit ubiquitous absorption and self-absorption features that are difficult to reconcile with emission arising solely from photodissociation regions associated with OB star clusters. We instead propose that these features originate in the photodissociated “skins” of molecular clouds externally illuminated by the ambient interstellar radiation field (ISRF). Meudon PDR models show that a standard Habing field produces surface layers with moderate optical depths in [C II] (τ ~ 0.5) and larger optical depths in [O I] (τ ~ 2–5), along with subthermal excitation temperatures (Tₑₓ ~ 10–20 K). Under these conditions, the surface layers naturally produce absorption against bright continuum sources and self-absorption against bright line emission. Detailed modeling of the Nessie A cloud reproduces the observed line profiles well. An examination of the HYGAL SOFIA survey toward 25 bright continuum sources shows that these features are common, including absorption or self-absorption at the systemic velocity of the star-forming cloud, multiple absorption components from foreground clouds at distinct velocities, and systematically stronger absorption in [O I] than in [C II]. Because all clouds are exposed to the ISRF, this mechanism is likely widespread. In extragalactic observations, coarse spectral resolution can wash out these absorption features, leading to a significant underestimate of the intrinsic [C II] and [O I] line emission. --------------------------------------------------------- * 今後の講演予定 [#ac94b97b] |BGCOLOR(cyan):#|BGCOLOR(cyan): Date|BGCOLOR(cyan):Speaker|BGCOLOR(cyan):Title|BGCOLOR(cyan):Chair| |440|2026年4月16日(木) 15:00-16:00 | Joss Bland-Hawthorn (Director, Sydney Institute for Astronomy, U Sydney) | The long-term evolution of turbulent discs in high-redshift galaxies | 天文教室と共催 | |441|2026年5月28日(木) 15:30-16:30 | James Jackson (NRAO, USA) | [C II] and [O I] Absorption and Self-Absorption from the “Skins” of Clouds | I. Sakon | *終了した談話会(2026年度) [#h9b1f387] 詳細はこちら: [[令和8(2026)年度談話会]] |BGCOLOR(cyan):#|BGCOLOR(cyan): Date|BGCOLOR(cyan):Speaker|BGCOLOR(cyan):Title|BGCOLOR(cyan):Chair| |440|2026年4月16日(木) 15:00-16:00 | Joss Bland-Hawthorn (Director, Sydney Institute for Astronomy, U Sydney) | The long-term evolution of turbulent discs in high-redshift galaxies | 天文教室と共催 | |439|2026年4月14日(火) 16:15-17:15 | Donald Figer (Rochester Institute of Technology, USA) | Photon Counting CMOS Imaging Detectors for Optical and UV Astrophysicss | 天文教室と共催 | --------------------------------------------------------- *これまでの談話会 [#e657f394] -[[令和8(2026)年度談話会]] -[[令和7(2025)年度談話会]] -[[令和6(2024)年度談話会]] -[[令和5(2023)年度談話会]] -[[令和4(2022)年度談話会]]（天文学教育研究センター・天文学教室合同談話会） -[[令和3(2021)年度談話会]]（天文学教育研究センター・天文学教室合同談話会） -[[令和2(2020)年度談話会]] -[[平成31(2019)年度談話会]] -[[平成30 (2018) 年度談話会]] -[[平成29 (2017) 年度談話会]] -[[平成28 (2016) 年度談話会]] -[[平成27 (2015) 年度談話会]] -[[平成26 (2014) 年度談話会]] -[[平成25 (2013) 年度談話会]] -[[平成24 (2012) 年度談話会]] -[[平成23 (2011) 年度談話会]] -[[平成22 (2010) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H22.html]] -[[平成21 (2009) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H21.html]] -[[平成20 (2008) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H20.html]] -[[平成19 (2007) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H19.html]] -[[平成18 (2006) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H18.html]] -[[平成17 (2005) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H17.html]] -[[平成16 (2004) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H16.html]] -[[平成15 (2003) 年度談話会:http://www.ioa.s.u-tokyo.ac.jp/danwakai//past/danwakai_H15.html]]
