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国立天文台野辺山談話会 : NRO Colloquium

日時
  • 毎週火曜日 15:00-16:00
場所
  • 国立天文台野辺山宇宙電波観測所 輪講室 (本館2階)

都合により、日時・場所は変更になることがあります。
問い合わせ、講演希望・推薦は、談話会世話人までご連絡ください。

次回のお知らせ

日時 / 場所 2017/02/21 (火), 14:00-15:00 / 輪講室
講演者 Arzoumanian Doris (Univ. of Nagoya)/
Shimajiri Yoshito (CEA/Saclay)
タイトル Characterizing interstellar filaments: Insights into the initial conditions for star formation (Arzoumanian)/
Universality of the relationship between the star formation rate and the mass of dense gas (Shimajiri)
概要 [Arzoumanian]
The highly filamentary structure of the interstellar medium is now impressively revealed by Herschel and Planck images tracing the Galactic cold dust emission. In particular, Herschel images, show that dense filaments observed in molecular clouds are associated with the main sites of star formation, demonstrating their key role in the star formation process. I will present the properties of the filamentary structures observed in the interstellar medium. These observational results put strong constraints on theoretical models for the formation and evolution of interstellar filaments. I will also discuss what we have learned about the initial conditions of the star formation process from the fragmentation of self-gravitating filaments.
[Shimajiri]
Essentially the same relation between star formation rate (SFR) and mass of dense gas above the threshold (Mdense) is found in nearby clouds [SFR/Mdense=4.6x10^-8] and external galaxies [SFR/Mdense=1.8x10^-8]. They, however, used the different dense gas tracers. To investigate the universal star formation law converting the dense molecular gas into stars, wide-field mapping observations in the same dense gas tracers are crucial. We carried out wide-field line mapping observations in dense gas tracer HCN with a spatial resolution of ∼0.04 pc toward the Aquila, Ophiuchus, and Orion B clouds using the IRAM 30m, MOPRA 22m, and Nobeyama 45m telescopes in the on-the-fly mode. We also estimated the mass of dense gas, Mdense, from the Herschel column density toward the area above Av=8 mag. As a result, we found that α(Herschel−HCN) conversion factor spans a wide range of values of 35–454. The obtainedα(Herschel−HCN) values are much larger than those found in the external galaxies and are strongly correlated with the local FUV field strength. Theα(Herschel−HCN) values decrease as the strength of the FUV radiation field increases, scaling as α(Herschel−HCN)-fit = 332.2xG(0,total)^-0.23. The SFRs from the number count of the Class II objects in the observed clouds is estimated to be (1.0–22.0)x10^-6 Msun/yr. We found that the relationship between SFR and Mdense in our observing clouds can be expressed as SFR/Mdense = (1.5–3.5)x10^-8. The SFR-Mdense relation in our study is consistent with that of Lada et al. (2010). We estimated the dense gas mass for the external galaxies using our relation. We concluded that the relationship between the star formation rate and the mass of the dense gas in the external galaxies is likely to be similar to that in the nearby star-forming region. Our result supports the views that the relationship between the star formation rate and the mass of the dense gas, i.e., the star formation efficiency in dense gas, is quasi-universal on the scale from >10 kpc to 1-10 pc.
講演資料など

過去の談話会

日付 タイトル/講演者
2016-04-05 南極望遠鏡計画の進捗状況
中井直正 (筑波大学)
2016-04-19 ディスクダークマターによる渦巻銀河M33の回転曲線の解釈
福島登志夫(国立天文台天文情報センター)
2016-05-16 Deep Fields of Hubble Space Telescope
Robert Williams(Space Telescope Science Institute)
2016-08-01 Conference Report: SPIE Astronomical Telescopes + Instrumentation 2016
南谷哲宏 (野辺山宇宙電波観測所)
2016-08-23 ALMA Observations of a High-density Core, MC27/L1521F in Taurus: Dynamical Gas Interaction at the Possible Site of a Multiple Star Formation ほか
徳田一起 (大阪府立大学)
2016-09-06 ノベヤマの役割ー過去・現在・未来
長谷川哲夫 (国立天文台チリ観測所)
2016-11-15 FMLO-周波数変調局部発振器を用いた新しいミリ波サブミリ波分光手法の開発
谷口暁星 (東京大学天文学教育研究センター)
2016-12-14 広帯域 X 線スペクトルを用いた活動銀河核構造の理解
川室太希 (京都大学)
2017-1-17 (1) MMC制御装置の更新(倉上)、メトロロジーの検討(和田)、今期立ち上げ測定の結果報告(半田)
倉上富夫、和田拓也、半田一幸(NRO)
2017-1-17 (2) 近傍銀河における分子ガスの性質と銀河環境の関係
小山 舜平 (東京工業大学, ISAS/JAXA)
2017-1-24 JAOにおけるsoftware開発2012-2014など
齋藤正雄 (NRO)
2017-1-31 Stacking解析による銀河星間ガス量の進
中西裕之 (鹿児島大)
2017-02-07 分子雲衝突によるSpitzer Bubble の形成
服部有祐 (名古屋大学)
2017-02-14 Infrared and radio observations of interactions between the ISM and UV around Galactic massive star-forming regions
山岸 光義 (JAXA/ISAS)
2017-2-21 Characterizing interstellar filaments: Insights into the initial conditions for star formation/ Universality of the relationship between the star formation rate and the mass of dense gas
Arzoumanian Doris (Univ. of Nagoya)/ Shimajiri Yoshito (CEA/Saclay)

昨年度以前の談話会

世話人

2016年度

  • 宮本祐介

2015年度

  • 宮本祐介
  • 西村淳

2014年度

  • 岩井一正
  • 諸隈佳菜