11月24日（火）13：30～15：00 太陽系小天体セミナー zoom
Nov 24 Tue Solar System Minor Body Seminar
11月25日（水）13：30～15：00 NAOJ Science Colloquium zoom
Nov 24 Wed
11月25日（水）15：00～16：00 ALMA-J seminar zoom
Nov 25 Wed
11月25日（水）17：00～18：30 Solar and Space Plasma Seminar zoom
Nov 25 Wed
詳細は以下をご覧下さい。
11月24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24日（火曜日）13時30分～15時
- 場所
- zoom
- 講演者
- 土屋智恵
- 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25日（水）
- Campus
- Mitaka
- Seminar
- NAOJ Science Colloquium
- Regularly Scheduled/Sporadic
- Every Wednesday
- Date
- 2020 November 25
- Time
- 13:30-15:00
- Place
- Zoom
- Speaker
- Miho Ishigaki (NAOJ)
- Title
- Insights into early Galactic history from metal-poor stars
- Abstract
- Metal-poor stars are the main constituents of the stellar halo of the Milky Way, which is presumably one of the oldest stellar components of our Galaxy. Because of their pristine chemistry and long dynamical time, metal-poor stars provide rich information about the chemodynamical evolution of our Galaxy. Massive surveys of Galactic stellar populations such as SDSS and Gaia in the last 20 years have revealed an unprecedented number of substructures of metal-poor stars, which have revolutionized our understanding of the early Galactic history. Chemical elements in stellar atmosphere have been particularly powerful to infer birth environment of individual metal-poor stars. I would like talk about progress of observations of metal-poor stars in the past 10 years, mainly focusing on spectroscopic observations and their interpretation. I also discuss prospects with the Prime Focus Spectrograph on the Subaru Telescope to study relatively unexplored outer halo region of our Galaxy.
- Facilitator
- -Name：Akimasa Kataoka
11月25日（水）
- Campus
- Mitaka
- Seminar
- ALMA-J seminar
- Regularly Scheduled/Sporadic
- Every Wednesday
- Date and time
- 2020 Nov 25 15:00-16:00
- Place
- Zoom
- Speaker
- Matteo Leonardi
- Affiliation
- NAOJ
- Title
- Listening to the universe with gravitational waves
- Abstract
-
With the first direct detection of gravitational waves in 2015 by the LIGO detectors, gravitational wave astronomy was born. By detecting gravitational waves produces by stellar mass objects, we opened a new channel through which we can explore the universe. After the first detection, many other followed and up to now, almost one hundred gravitational waves telling the story of the last moments of compact binary coalescences have been detected by the LIGO and Virgo interferometers revealing many precedently untold information about our universe as we have never seen it.
Located in Japan, KAGRA is a new generation gravitational wave detector that will join the LIGO-Virgo network during the next observation run (O4). The addition of KAGRA to the network will lead to better sky coverage, sky localization and network duty-cycle, further increasing the amount of information we can extract from gravitational wave detections. - Facilitator
- Daisuke Iono, Andres Guzman
11月25日（水）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Sporadic
- Date and time
- 25 November (Wed), 17:00-18:30
- Place
- zoom
- Speaker
- Patrick Antolin
- Affiliation
- Northumbria University
- Title
- Nanojets of coronal heating
- Abstract
- The solar corona is shaped and mysteriously heated to millions of degrees by the Sun’s magnetic field. It has long been hypothesized that the heating results from a myriad of tiny magnetic energy outbursts called nanoflares, driven by the fundamental process of magnetic reconnection. Misaligned magnetic field lines can break and reconnect, producing nanoflares in avalanche-like processes. However, no direct and unique observations of such nanoflares exist to date, and the lack of a smoking gun has cast doubt on the possibility of solving the coronal heating problem. From coordinated multi-band high-resolution observations, we report on the discovery of very fast and bursty nanojets, the telltale signature of reconnection-based nanoflares resulting in coronal heating. The nanojet is uniquely characterised by being transverse to the loop and appears as a unidirectional jet from the reconnection point. Isolated and clustered nanojets are detected, and a myriad are observed in an avalanche-like progression, leading to the formation of a coronal loop. Using state-of-the-art numerical simulations, we demonstrate that the nanojet is a consequence of the slingshot effect from the magnetically tensed, curved magnetic field lines reconnecting at small angles. Nanojets are therefore the key signature of reconnection-based coronal heating in action.
- Facilitator
- -Name：Munehito Shoda