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*IoA Seminar 2017 / 平成29年度/2017年度・東京大学・天文学教育研究センター・談話会 [#l7b77500]
#contents
* Upcoming Seminars [#s0b11a2c]
** No. 312: October 12 (Thu), 2017, 15:30 - 16:30 [#bamba1]
** No. 313: October 26 (Thu), 2017, 15:30 - 16:30 [#bamba1]
*** Speaker: Jonathan Freundlich (Racah Institute of Physics, The Hebrew University) [#q1f6d218]
*** Speaker: Jürgen Stutzki (Universität zu Köln) [#m936f68b]
*** Title: Molecular gas reservoirs during the winding-down of star formation [#e0b4775f]
*** Title: Optical depth of the [CII] 158 um fine structure line emission: [#b12a7709]
high spectral resolution observations with SOFIA/upGREAT
Abstract: Star formation in the Universe decreased by an order of magnitude in the last ten billion years. Probing the molecular gas reservoirs from which stars are formed is crucial to understand this winding-down of star formation. The PHIBSS2 legacy program at the IRAM NOEMA interferometer surveys the molecular gas properties of galaxies at different redshifts on and around the main sequence, where most of star formation occurs. It notably contributes to show that the cosmic evolution of the star formation rate is mainly driven by that of the molecular gas fraction, albeit with a small inflexion of the star formation efficiency. At z=0.5-0.8, we observe the CO(2-1) line for 61 targets, from which we determine molecular gas masses, gas fractions and depletion times. We separately obtain disk sizes and bulge-to-total luminosity ratios, which enable us to characterize morphological changes. The Kennicutt-Schmidt relation between molecular gas and star formation rate surface densities is strikingly linear, which argues in favor of uniform star formation processes across cosmic time. Our results also suggest an ongoing supply of molecular gas to compensate for star formation and a contribution of disk stars to the growing bulge.
Abstract: The fine structure line of ionized carbon, [CII], at 158 μm is one of the strongest cooling lines of the dense interstellar medium. Located in the core region of the far-infrared spectral range, it is observable in the local universe only from space, balloon or airborne platforms, or at high redshifts in the ALMA bands, where it is used as tracer of star formation activity in early galaxies. The recent technological advances now allow routine highest spectral resolution heterodyne observations with the upGREAT instrument on board SOFIA, that resolve the [13CII] satellite lines with sufficient signal/noise, so that it is possible to measure directly the optical depth of the carbon fine structure line emission.
We have performed such observations in seven sources ranging from simple to complex spatial and kinematic morphology. In all cases, we find clear evidence of significant optical depth. In many cases, the line profiles show clear evidence for foreground or self-absorption. The high column densities derived and, in many cases, the low temperatures of the foreground/self-absorption, are difficult to account for in standard model scenarios of photodissociation regions (PDRs). These findings imply, that one has to use with caution integrated line intensity ratios, when interpreting [CII] observations in the context of PDR models, to infer average properties of spectroscopically and spatially unresolved sources.
Language: English
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** 趣旨 [#u5a10e1e]
東京大学・天文学教育研究センターでは2003年4月から, [[院生コロキウム:http://www.ioa.s.u-tokyo.ac.jp/colloquium/wiki/]]に引き続き, 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.
**日時 [#ca76a702]
-木曜日
-15:30-16:30
**場所 [#hd64d995]
-天文センター講義室
**標準タイムテーブル [#o43df0c8]
|13:30-14:30|[[院生コロキウム:http://www.ioa.s.u-tokyo.ac.jp/colloquium/wiki/]]|講義室|
|15:30-16:30|談話会|講義室|
|16:30-|お茶の時間|講義室横のお茶部屋~講師の方を交えて~|
**世話人 [#eb289931]
please replace _at_ to @
-Masaki YAMAGUCHI 山口正輝: masaki _at_ ioa.s.u-tokyo.ac.jp
-Masuo TANAKA 田中培生: mtanaka _at_ ioa.s.u-tokyo.ac.jp
-Toshihiko TANABE 田辺俊彦: ttanabe _at_ ioa.s.u-tokyo.ac.jp
-Kotaro KOHNO 河野孝太郎: kkohno _at_ ioa.s.u-tokyo.ac.jp
** Schedule [#r149116c]
|BGCOLOR(cyan):#|BGCOLOR(cyan): Date|BGCOLOR(cyan):Speaker|BGCOLOR(cyan):Title|BGCOLOR(cyan):Chair|
|312|2017/10/12 (Thu) 15:30 - 16:30|Jonathan Freundlich (Racah Institute of Physics, The Hebrew University)| Molecular gas reservoirs during the winding-down of star formation ||
|312|2017/10/12 (Thu) 15:30 - 16:30|Jonathan Freundlich (Racah Institute of Physics, The Hebrew University)| Molecular gas reservoirs during the winding-down of star formation |MY|
|313|2017/10/26 (Thu) 15:30 - 16:30|Juergen Stutzki (Universitaet zu Koeln)| Optical depth of the Carbon 158 um line emission: high spectral resolution observations with SOFIA/upGREAT |KK|
|31X|2017/11/16 (Thu) 15:30 - 16:30|藤澤幸太郎 (早稲田大学)| TBA | |
|31X|2017/12/07 (Thu) 15:30 - 16:30|小西美穂子 (NAOJ Fellow)| TBA | |
**終了した談話会(2017年度) [#ufca90a6]
詳細はこちら: [[平成29 (2017) 年度談話会]]
|BGCOLOR(cyan):#|BGCOLOR(cyan): Date|BGCOLOR(cyan):Speaker|BGCOLOR(cyan):Title|BGCOLOR(cyan):Chair|
|301|2017/4/13 (Thu) 15:30 - 16:30|Tao WANG (IoA/U.Tokyo (4月から))| New insights into the formation of the most massive galaxies at high redshifts |KK|
|302|2017/4/20 (Thu) 15:30 - 16:30|Matthew W. Johns (U. Arizona)| The Magellan Experience - Building a 6.5 Meter Optical/Infrared Telescope |TT|
|303|2017/4/27 (Thu) 15:30 - 16:30|滝脇知也 (国立天文台 理論部)| 重力崩壊型超新星の爆発機構 |MY|
|304|2017/5/11 (Thu) 15:30 - 16:30|樫山和己 (東京大学 物理学専攻)| A FRB in a bottle |MY|
|305|2017/5/25 (Thu) 15:30 - 16:30|西村優里 (天文学教育研究センター (4月から))| 低重元素量の矮小銀河における分子雲の化学組成 |KK|
|306|2017/6/1 (Thu) 15:30 - 16:30|片岡章雅 (国立天文台フェロー)| Millimeter-wave polarization as a tool of investigating the planet formation |KK|
|307|2017/6/15 (Thu) 15:30 - 16:30|端山和大 (東京大学 宇宙線研)| 重力波望遠鏡の現状と、検出から物理へ |MT|
|308|2017/6/22 (Thu) 15:30 - 16:30|福島登志夫 (国立天文台)|宇宙人存在問題 Question on Alien Civilization Existence|TT|
|309|2017/7/13 (Thu) 15:30 - 16:30|Ryan M. Lau (Caltech/JPL)|High Energy, Cool Transients: Investigating Infrared-Luminous Outbursts with Spitzer|KK|
|310|2017/7/20 (Thu) 15:30 - 16:30|木坂将大 (青山学院大学)| 多波長観測で探るパルサー磁気圏構造 |MY|
|311|2017/7/27 (Thu) 15:30 - 16:30|馬場彩 (東京大学 物理学専攻)| 超新星残骸のX線観測に関する最近の話題 |MY|
**これまでの談話会 [#ge2d9f79]
-[[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]]
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