4月25日（火）13：30～15：00 太陽系小天体セミナー 南棟２階会議室
Apr 25 tue Solar System Minor Body Seminar Conference Room, South Bldg.2F
4月26日（水）10：30～12：00 総研大コロキウム 中央棟 講義室
Apr 26 wed SOKENDAI colloquium Lecture Room
4月26日（水）13：30～14：30 理論コロキウム コスモス会館会議室
Apr 26 wed DTA colloquium Conference Room, Cosmos Lodge
4月27日（木）14：00～15：00 太陽系科学セミナー 院生セミナー室（TV会議：水沢RISE会議室）
Apr 27 thu Solar System Science Seminar Student Seminar Room, Subaru Bldg.
(TV conference, Mizusawa RISE meeting room)
4月28日（金）13：30～15：00 太陽天体プラズマセミナー 院生セミナー室
Apr 28 fri Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
4月28日（金）16：00～17：00 国立天文台談話会 大セミナー室
Apr 28 fri NAOJ Seminar Large Seminar Room
詳細は以下をご覧下さい。
4月25日（火）
- キャンパス
- 三鷹
- セミナー名
- 太陽系小天体セミナー
- 定例・臨時の別
- 定例
- 日時
- 4月25日（火曜日）13時30分～15時
- 場所
- 南棟２階会議室
- 講演者
- 藤原康徳
- 連絡先
- 名前：渡部潤一
- 備考
- テレビ会議またはスカイプによる参加も可
4月26日（水）
- Campus
- Mitaka
- Seminar
- SOKENDAI colloquium
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- April 26 2017, 10:30-12:00
- Place
- Lecture Room
- Speaker1
- Tomonari Michiyama
- Affiliation
- SOKENDAI D2 (Supervisor; Daisuke Iono)
- Title
- Dense molecular outflows from the merging LIRG NGC3256 Abstract :
We report the new ALMA Cycle 3 results of line survey towards a late stage merging galaxy NGC 3256. NGC 3256 hosts two merging nuclei and the starburst and AGN activities are strongly affecting the chemical and physical properties of the ISM. We have detected more than 20 molecules (e.g., c-C3H2, H13CN, H13CO+, SiO, CCH, HCN, HCO+, HNC, CH3OH, CS, HC3N, CH3CCH, C18O, 13CO) at 2” angular resolution, which is high enough to resolve the double nuclei. In this presentation, we focus on CO, HCN and HCO+ to discuss the high velocity components detected only by those bright molecular lines. Such high velocity components are though to be molecular gas outflow from northern and southern nuclei. Including the CO(1-0) and CO(3-2) archived data, the line ratios suggest that (1) The excitation condition become weak towards edge of the outflow in the starburst triggered outflow. (2) In the case of low luminous AGN like southern nucleus in NGC 3256, the outflowing gas is associated with AGN jet, and warm and dense gas can be newly formed due to interaction between jet and ISM interaction.
(3) The HCN is enhanced due to shock especially in red-shifted outflow. In addition, we conducted radiative transfer modeling. By using a Bayesian likelihood analysis, we found that the CO column density and filling factor of outflowing gas is smaller than the gas around nuclei. - Speaker2
- Satoshi Kikuta
- Affiliation
- SOKENDAI D1 (Supervisor; Masatoshi Imanishi)
- Title
- Lyman-alpha emission as a tool to probe galaxy formation Abstract :
Lyman-alpha emission line is the strongest line from astrophysical sources and can be used to probe galaxy formation especially at high-redshift (z>2) Universe. In this talk, I will review the basic physics about Lyman-alpha line and recent works on galaxy formation which used the line. Finally I will also talk about my research plan using the Lyman-alpha line from the gas in young galaxies around bright QSOs at z~3 to study the importance of gas in galaxy formation. - Facilitator
- -Name：Misaki Ando
- Comment
- TV conference system is available connecting from Nobeyama, Hawaii, Mizusawa, and Okayama.
4月26日（水）
- Campus
- Mitaka
- Seminar
- DTA colloquium
Regularly Scheduled - Date and time
- 26 April 2017, 13:30-14:30
- Place
- Conference Room, Cosmos Lodge
- Speaker
- Tomohisa Kawashima
- Affiliation
- NAOJ
- Title
- Radiation hydrodynamic simulations of super-critical accretion columns onto neutron stars in ULX-pulsars
- Abstract
- Ultraluminous X-ray sources are off-centered, extragalactic X-ray sources with luminosities exceeding the Eddington limit for stellar-mass black holes. After the recent discovery of pulsed X-ray emissions in three ULXs, it is widely thought that some ULXs are powered by super-critical column accretion onto neutron stars. The mechanism of super-critical column accretion is, however, still poorly understood. We have, therefore, carried out two-dimensional radiation hydrodynamic simulations of super-critical accretion columns onto neutron stars, and have found that the super-critical accretion can be realized because the most photons escape from the side wall of accretion columns (i.e., the radiation field is anisotropic in the accretion columns). The simulated accretion columns are luminous enough to be consistent with the observed ULX-pulsars.
- Facilitator
- -Name：Tomoya Takiwaki
- Comment
- in English
4月27日（木）
- キャンパス
- 三鷹
- セミナー名
- 太陽系科学セミナー
- 定例・臨時の別
- 定例
- 日時
- 4月27日（木曜日）14時～15時
- 場所
- 院生セミナー室（TV会議：水沢RISE会議室）
- 講演者
- 脇田茂
- タイトル
- Active Asteroids as Science Targets
- Abstract
- 小惑星の中にはダストの放出や、彗星のコマのようなものなどが観測
されているものがある。Active Asteroids（もしくはMain belt comets）と呼ば
れるこのような小惑星をJewitt et al. (2015)のreviewを行いながら紹介すると
共に、現状での理解・不明点などを整理する。 - 連絡先
-
-名前：脇田茂
-名前：松本晃治
-名前：土屋智恵 - 備考
- テレビ会議またはスカイプによる参加も可
4月28日（金）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 28 April (Fri), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Bernhard Kliem
- Affiliation
- University of Potsdam, Institute of Physics and Astronomy
- Title
- Flux Rope Instabilities in Solar Eruptions
- Abstract
-
This talk will give an overview of the modeling of solar eruptions which are observed as filament/prominence eruptions, coronal mass ejections, and flares. Basic considerations of energy storage in the solar corona suggest the existence of an ideal magnetohydrodynamic (MHD) instability or catastrophe, a lateral kink referred to as torus instability. This instability can naturally explain the onset of eruptions and their main acceleration. Additionally, the helical kink instability may trigger the eruption in some cases. However, both instabilities require the existence of a magnetic flux rope at eruption onset. This used to be less well supported by the observations than the alternative configuration of a magnetic arcade, but recent data and modeling provide increasing support. The instabilities also lead to the formation of a large-scale vertical current sheet, where magnetic reconnection causes the flare signatures. The alternative reconnection-dominated eruption models only require a magnetic arcade at eruption onset, but must assume that a process of self-amplifying reconnection exists, which has not yet been unambiguously demonstrated. All relevant eruption models in the literature can be understood in terms of the above two categories.
Finally, some open aspects of ideal MHD instability-dominated models will be discussed: the timing, coherence, and specific topology of the implied flux rope before the onset of eruption. - Facilitator
- -Name：Shin Toriumi
- Comment
4月28日（金）
- キャンパス
- 三鷹
- セミナー名
- 国立天文台談話会
- 定例・臨時の別
- 定例
- 日時
- 4月28日（金） 16:00-17:00
- 場所
- 大セミナー室
- 講演者
- Jonathan C. Tan
- 所属
- Univ. of Florida
- タイトル
- “A Light in the Dark – Massive Star Birth Through Cosmic Time”
- Abstract
-
Massive stars have played a dominant role in shaping our universe since its earliest times, but there is still no consensus on the mechanism by which they form. I review the physics important for massive star formation and the intimate connection this process has with star cluster formation. I then focus on a particular theoretical model, Turbulent Core Accretion, which assumes the initial conditions are massive, turbulent, magnetized cores of gas and dust that are reasonably close to virial equilibrium. Our group has been exploring this scenario via analytic models and numerical simulations of the physics and chemistry of the interstellar medium.
Crucially, these models can now be tested in detail with ALMA and I present the latest results from multiple projects that are zooming in to massive star birth in the darkest shadows of giant molecular clouds. Extension of this work has the potential to also determine how the full stellar initial mass function is established across different Galactic environments. I then switch to the protostellar accretion phase and the emergence of feedback processes, presenting both theoretical predictions and observational tests. Finally, I discuss an application of massive star formation theory to the early universe: how massive were the first stars and could they have been the progenitors of supermassive black holes? - 連絡先
- -名前：松田 有一
以上