2月29日（月）15：00～16：00 国立天文台野辺山談話会 野辺山観測所本館 輪講室
Feb 29 Mon Nobeyama NAOJ Seminar Rinko-shitsu, Main building, NRO
3月2日（水）15：00～16：00 理論コロキウム 中央棟（北）1F講義室
Mar 2 Wed DTA Colloquium Lecture Room
3月4日（金）11：00～12：00 赤外ゼミ すばる棟3F TV会議室
Mar 4 Fri Infrared Seminar TV Conference Room, Subaru bldg.3F
3月4日（金）16：00～17：00 国立天文台談話会 大セミナー室
Mar 4 Fri NAOJ Seminar Large Seminar Room
詳細は以下をご覧下さい。
2月29日(月)
- キャンパス
- 野辺山
- セミナー名
- 国立天文台野辺山 談話会
- 定例・臨時の別
- 臨時
- 日時
- 2月29日（月曜日） 15:00 ～16:00
- 場所
- 野辺山宇宙電波観測所 本館 輪講室
- 講演者
- Dragan SALAK 氏
- 所属
- Kwansei Gakuin University
- タイトル
- The ALMA view of nearby galaxies: Observations of the barred starburst galaxy NGC 1808
- Abstract
-
In recent years, we have witnessed a revolution in astronomy owing to the Atacama Large Millimeter/submillimeter Array (ALMA). In this talk, I present the results from the first ALMA observatons of NGC 1808, a nearby barred starburst galaxy with an outflow. Large-field CO (J=1-0) observatons at high resolution (2” or 100 pc) reveal molecular gas in
(1) a circnumnuclear disk (R<200 pc), (2) 500-pc ring, (3) gas-rich bar, and (4) galactic disk. On the galactic scale, giant molecular cloud complexes (1e6-1e7 Msun) are detected in the bar region with prominent velocity gradient (shear). I discuss the star formation and molecular-cloud evolution in the bar based on the observed CO-Hα offsets, shear, and velocity dispersion. In the inner R<500 pc region, we find evidence of a warp and non-circular motions due to a nuclear spiral arm and outflow. Deconvolution of the central rotation curve reveals multiple mass components including a massive core (1e7 Msun) within R<50 pc. - 連絡先
- 名前：宮本祐介
- 備考
- テレビ参加可
3月2日(水)
- Campus
- Mitaka
- Seminar
- DTA colloquium
- Regularly Scheduled/Sporadic
- Sporadic
- Date and time
- 2 Mar 2016, 15:00-16:00
- Place
- Lecture Room
- Speaker
- Yichen Zhang
- Affiliation
- Chile/Yale
- Title
- Star Formation across the Mass Spectrum and Environments
- Abstract
- One of the major question in star formation is whether high and low-mass stars form in a similar way by accreting from pre-existing cores (core accretion). My talk will be around three aspects of this question. First, in the core accretion scenario, the outflow feedback is believed to be responsible for dispersing the core and regulating the core-to-star efficiency. I will present results of our recent ALMA observation of the low-mass HH 46/47 molecular outflow to understand the outflow feedback. Using 13CO and C18O emission to correct for the 12CO optical depth and trace denser and slower outflow material than 12CO only, we accurately estimated the mass, momentum and kinetic energy of the outflow. The estimated outflow properties indicate that the outflow is capable to disperse the parent core within the typical lifetime of the embedded phase of a low-mass protostar, and is regulating the core-to-star efficiency to about 1/4 to 1/3. This new observation also reveals a rotating/infalling envelope, a spinning outflow, and detailed outflow structures which help us to understand the outflow entrainment process. Second, through radiation transfer (RT) simulation, predictions of core accretion model and continuum observations of massive protostars are compared. I will introduce our evolutionary model of (massive) star formation based on the core accretion, which self-consistently includes protostellar evolution, collapse of the core, growth of the disk, and gradual opening-up of the outflow cavity. In such a framework, the evolutionary tracks are determined by the initial environmental conditions: the initial core mass, the mass surface density of the ambient clump, and the rotation of the core. Through RT simulations, we are able to produce temperature structures, SED, IR continuum images of protostars at different evolutionary stages under various initial conditions. I will show an example that such a model can interpret the multiwavelength observations of massive protostars. Third, the core accretion theory also predicts that the thermal/chemical evolution of protostellar cores can be strongly affected by the star-forming environment, e.g. a low-mass-surface-density region where low-mass stars form in relative isolation, like Taurus, vs. a crowded high-mass-surface-density region, like Orion. I will discuss this effect by combining the above RT model with simple chemical models.
- Facilitator
- -Name: Tsuyoshi Inoue
- Comment
- English
3月4日(金)
- キャンパス
- 三鷹
- セミナー名
- 赤外ゼミ
- 定例・臨時の別
- 定例
- 日時
- 3月 4日（金曜日） 11時 ～ 12時
- 場所
- すばる棟3階TV会議室(IP: 133.40.2.249)
- 講演者
- 馬場 はるか
- 所属
- 総合研究大学院大学
- タイトル
- 論文紹介: A search for very low mass stars and brown dwarfs in the young σ
Orionis cluster - Abstract
- この論文ではσ Orionis clusterの870平方度のR,I,Aバンドによる測光観測を行い、色-等級図選択により49天体を検出した。これらの天体についてOrion 1b associationの年齢2-10 Myrを適用し進化モデルを考慮したところ、質量は0.02-0.1太陽質量となった。これらの天体のうちIバンド等級が16-19.5等の8天体の分光フォローアップしたところスペクトル型がM6-M8.5となり、星団メンバーであることが確認された。このほか、このような若い低質量天体の研究において重水素を用いる方法について議論している。
- 連絡先
- -名前：楊 毅
3月4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
- 3月4日（金） 16:00-17:00
- 場所
- 大セミナー室
- 講演者
- Dennis Crabtree
- 所属
- Herzberg Astronomy and Astrophysics, National Research Council Canada
- タイトル
- A bibliometric analysis of observatory publications for the period 2009-2013
- Abstract
- The primary scientific output from an astronomical telescope is the collection of papers published in refereed journals. A telescope’s productivity is measured by the number of papers published which are based upon data taken with the telescope. The scientific impact of a paper can be measured quantitatively by the number of citations that the paper receives. In this paper I will examine the productivity and impact of over 25 telescopes, mainly optical/IR, with apertures larger than 3.5-m for the years between 2009 and 2013. I will also examine how the telescopes are connected via their publications as well as the productivity and impact of individual instruments for several telescopes.
- 連絡先
- -名前： 阿久津 智忠
以上