11月10日（火）13：30～14：30 ATCセミナー Zoom
Nov 10 Tue ATC Seminar
11月10日（火）13：30～15：00 太陽系小天体セミナー Zoom
Nov 10 Tue Solar System Minor Body Seminar
11月11日（水）13：30～15：00 NAOJ Science Colloquium Zoom
Nov 11 Wed
11月11日（水）15：00～16：00 ALMA-J seminar Zoom
Nov 11 Wed
11月13日（金）13：30～15：00 Solar and Space Plasma Seminar Zoom
Nov 13 Fri
11月13日（金）16：00～17：00 談話会 Zoom webinar
Nov 13 Fri NAOJ Seminar
詳細は以下をご覧下さい。
11月10日（火）
- キャンパス
- 三鷹
- セミナー名
- ATCセミナー
- 定例・臨時の別
- 臨時
- 日時
- 11月10日（火曜日）13時30分～14時30分
- 場所
- Zoom
- 講演者
- 中野 雅之 氏
- 所属
- 東京大学 宇宙線研
- タイトル
- 重力波観測機KAGRAにおける干渉計制御
- Abstract
-
KAGRAは現在日本で建設が進められている重力波検出器である。2020年4月には初の本格観測を行い、現在は次回観測に向けたアップグレード作業を行なっている。
KAGRAは他の大型重力波検出機と同様に、3kmの基線長をもつ大型干渉計を使い重力波を検出する。高感度の重力波観測機を実現するためには、多くの雑音を十分下げる必要がある。KAGRAでは、地面振動の小さい岐阜県飛騨市の神岡鉱山地下に建設し、鏡の20Kの極低温に冷却することで、鏡の熱振動によ る雑音を低減する。これらは他の重力波観測機には無い特徴であり、他の重力波観測機が第2世代と呼ばれているのに対し、これらの特徴によりKAGRAは2.5 世代と呼ばれている。
重力波観測機では干渉計を構成する鏡を制御し、鏡間の距離を観測点に保つ必要がある。この制御は多自由度の系の制御であり、さらに鏡の制御信号の線形域は1nm以下と非常に小さいため、体系的な制御手法の開発が重要となる。4月の観測では3kmのMichelson干渉計の各腕に組み込まれたFabry-Perot共振器、また、パワーリサイクル共振器と呼ばれる共振器の計3つの共振器を組み合わせたPower recycling Fabry-Perot Michelson干渉計と呼ばれる干渉計構成で観測を行なった。一方次回の観測ではさらにもう１つの共振器を組み合わせたDural Recycling Fabry-Perot Michelson(DRFPMI)干渉計と呼ばれる干渉計構成での観測を予定している。現在はこのDRFPMIの制御実験が行われている。
今回の講演では、前回の観測時に感度を制限していた雑音や干渉計の制御に焦点を当て、KAGRAの現状について説明する。 - 連絡先
- -名前：永井 誠
- 備考
- 日本語での講演
11月10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
- 11月10日（火曜日）13時30分～15時
- 場所
- zoom
- 講演者
- 石村周平
- 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
11月11日（水）
- Campus
- Mitaka
- Seminar
- NAOJ Science Colloquium
- Regularly Scheduled/Sporadic
- Every Wednesday
- Date
- 2020 November 11
- Time
- 13:30-15:00
- Place
- Zoom
- Speaker
- Ryosuke Hirai (Monash Univ.)
- Title
- Impact of supernova explosions on binary companions and its diverse implications
- Abstract
- Stripped-envelope supernovae are a subclass of core-collapse supernova explosions that lack hydrogen in their spectra. The current prevailing theory is that the outer hydrogen layer of the supernova progenitor was removed through interactions with a binary companion. If this is the case, the binary companion should still remain in the aftermath of the supernova, with possible traces of it being impacted by the explosion. Many attempts have been made to confirm the existence of a remaining companion in the remnants of stripped-envelope supernovae. Some cases have led to a successful detection such as SN2006jc. On the other hand, some cases such as Cassiopeia A have strong constraints on any remaining companion posing a serious problem for the binary hypothesis. In this talk, I will discuss the outcomes of supernova explosions in binary systems and what we can learn from post-supernova companion detections and non-detections. In particular, I will present a new scenario for the formation of single stripped-envelope supernova progenitors, that can explain the origin of the Cassiopeia A progenitor.
- Facilitator
- -Name：Akimasa Kataoka
11月11日（水）
- Campus
- Mitaka
- Seminar
- ALMA-J seminar
- Regularly Scheduled/Sporadic
- E very Wednesday
- Date and time
- 2020 Nov 11 15:00-16:00
- Place
- Zoom
- Speaker
- Fernando Olguin
- Affiliation
- National Tsing Hua University
- Title
- Digging into the high-mass core G335.579-0.292 MM1
- Abstract
- Characterizing the kinematics of massive cores is key to understanding how high-mass stars in single or multiple systems form. Since high-resolution observations are needed to resolve individual cores, we are carrying a survey to look for binary/multiple systems in high-mass star forming regions with ALMA. One of the youngest and most massive star forming region in the Galaxy is located within the IRDC SDC335.579-0.272. Large scale infall motions have been observed in this region (Peretto et al. 2013), whilst ALMA and ATCA observations have started to resolve individual cores (Avison et al. 2015). In this presentation we will show 1.3 mm ALMA observations probing scales of 1000 au that reveal a small clump of sources, with 2 sources likely forming high-mass stars. The line emission from the most massive core provides evidence of rotation and infall motions at large and small scales, while hot molecules trace the expanding motions towards the central region. The other core shows clear signs of rotation of an envelope and/or disc-like structure. Finally we will show results of our ongoing analysis of even higher angular resolution ALMA observations probing ~200 au scales.
- Facilitator
- -Daisuke Iono, Andres Guzman
11月13日（金）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 13 November (Fri), 13:30-15:00
- Place
- zoom
- Speaker
- Noriyuki Narukage
- Affiliation
- NAOJ
- Title
- The dawn of the solar X-ray focusing imaging-spectroscopy era
- Abstract
-
The solar corona is a natural laboratory for studying the behavior and property of high-energy plasma, such as plasma heating, eruption, particle acceleration and so on. For the understanding of these
physics, we are evolving the new observation technique, “X-ray focusing imaging-spectroscopy”, with the combination between X-ray mirror and high-speed X-ray camera. This is one of the ideal
observations for the solar corona, since it can realize spatial-, temporal- and spectral-resolutions and high dynamic-range, simultaneously, for the X-rays that contain rich information about
high-energy electrons, namely, electron temperature, electron density, ion abundance, non-thermal electron power-low index, etc. In this seminar, I will introduce my recent activities to realize this
observation. From the FOXSI-3 sounding rocket project that realized the soft X-ray focusing imaging-spectroscopic observation of the solar corona for the first time, I will show new (preliminary)
results from on-going analysis. The new project, FOXSI-4 solar flare campaign to be executed in 2024, will be introduced. Additionally, I will introduce the MinXSS CubeSat mission that is a very small
spectrometer (no spatial resolution) but successfully obtained the soft X-ray spectra in many solar flares during its one-year observation period. - Facilitator
- -Name：Munehito Shoda
11月13日（金）
- Campus
- Mitaka
- Seminar
- NAOJ Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 13 November (Fri), 16:00-17:00
- Place
- zoom webinar
- Speaker
- Keiko Kokeyama
- Affiliation
- KAGRA Observatory, ICRR, The University of Tokyo
- Title
- Status of KAGRA, underground cryogenic gravitational wave telescope
- Abstract
-
Gravitational-wave astronomy began with the binary black hole mergers detected by LIGO in 2015. Followed by the first detection, a binary neutron star merger was discovered by LIGO and VIRGO in 2017. This neutron star merger event was identified and observed by other kinds of observatories, revealing various science cases in astrophysical and fundamental physics.
KAGRA is an underground and cryogenic gravitational-wave telescope, built in Gifu, Japan. From Apr 7–21, 2020, KAGRA’s first international joint observation performed with GEO 600, which is a British-German detector having a similar sensitivity to that of KAGRA. This observation is called O3GK.
KAGRA is aiming to join the next LIGO-VIRGO observation, called O3. KAGRA will be a fourth detector in the observation network, expecting to improve sky localizations and to add more information of gravitational-wave nature. Currently, all of KAGRA, LIGO, and VIRGO detectors are now offline for detector upgrades to achieve a better sensitivity for the next observation.
In this talk, KAGRA’s performance during O3GK will be presented, as well as the status of the detector upgrades. Also, we will report the prospects of the gravitational-wave field. - Facilitator
- -Name：Shimojo, Masumi