Jun 2 Wed 15:00～16:00 ALMA-J seminar zoom
Jun 2 Wed 15:30～17:00 NAOJ Science Colloquium zoom
Jun 3 Thu 13:00～14:00 Tea Talk zoom
Jun 4 Fri 16:00～17:00 NAOJ Seminar zoom
詳細は以下をご覧下さい
6月2日（水）
Campus: Mitaka
Seminar: ALMA-J seminar
Date and Time: 2021 June 2, 15:00-16:00
Place: Zoom
Speaker：Takuya Akahori (NAOJ/SKAO)
Title：SKAO Science Highlight
Abstract：
Square Kilometre Array Observatory (SKAO) is one of the world-largest radio astronomy projects. SKAO will operate LOW and MID telescopes covering the observing frequency from 50 MHz to 15 GHz at the phase 1, and up to 50 GHz at a later phase. The construction of SKAO will start in this year (2021). In the last decades, diverse science objectives have been proposed for SKAO, and the SKAO pathfinder and precursor telescopes are taking a glimpse of the SKA science. In this talk, I will briefly look around SKA science objectives such as (i) Galaxy evolution, cosmology and dark matter, (ii) Strong-field tests of gravity using pulsars and black holes, (iii) The origin and evolution of cosmic magnetism, (iv) Probing the Cosmic Dawn, (v) The cradle of life, and (vi) Flexible design to enable exploration of the unknown. I will comment possible synergies with ALMA.
Facilitator: Yuichi Matsuda, Yusuke Miyamoto
6月2日（水）
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday
Date and time：2021 June 2, 15:30-17:00
Place：zoom
Speaker：Sakemi Haruka
Affiliation：NAOJ
Title: Cosmic-ray Particle Acceleration by Galactic Microquasar Jets
Abstract:
Cosmic-ray particles occupy a large portion of the energy distribution of our galaxy. Most of the particles below 10^15 eV are considered to be accelerated by diffusive shock acceleration (DSA) at galactic supernova remnants (SNRs). However, the origin of the particles in the energy range of 10^15-10^18 eV has not been explained yet. Recently, galactic microquasar jets are focused on as a candidate accelerator in this energy range, and theoretical and observational studies get active to investigate the dominant mechanism of acceleration and the energetics.
We focus on the most famous microquasar, SS433. It is located at the center of a large radio nebula W50, and the nebula and the jets ejected from SS433 are considered to be interacting. Along the eastern jet axis, there are two candidate regions in which cosmic-ray particle acceleration may occur. One is the region at which the jet broke through W50, and recent HAWC observation identified a TeV gamma-ray emission from the point. The other is the jet terminal region in which the terminal shock should be formed and bright at radio and X-ray. We investigated the jet terminal region using the observational data with the Australia Telescope Compact Array (ATCA) and the NSF’s Karl G. Jansky Very Large Array (VLA) at a few GHz. We revealed the features of magnetic fields and motion of this region, and finally estimated the maximum energy which can be reached by the particle acceleration at the jet terminal shock. We also estimated the total energy of cosmic-ray particles accelerated by the SS433/W50 system based on the observations of HI gas and the gamma-ray emission. In this presentation, I will review my research and future plan.
Facilitator
-Name：Akimasa Kataoka
Comment：English
6月3日（木）
キャンパス：三鷹
セミナー名：Tea Talk
定例・臨時の別：臨時
日時：6/3（木）13：00～14：00
場所：Zoom
講演者：倉崎 高明
所属：台長特別補佐
タイトル：「はやぶさ２」広報対応の経験と世間一般から見た天文学
※後半に渡部副台長がお話の聞き手としてご参加される予定です。
世話人の連絡先：
-名前：藤田登起子
備考：
参加方法：Zoom
6月4日（金）
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Scheduled
Date and time：2021 Jun 4, 16:00～17:00
Place：zoom
Speaker：秦 和弘 / Hada, Kazuhiro
Affiliation：水沢ＶＬＢＩ観測所 / Mizusawa VLBI Observatory
Title：M87巨大ブラックホール観測の最近の進展
Abstract：
2019年4月、Event Horizon Telescope (EHT) Collaborationは活動銀河M87の中心にある
巨大ブラックホール(SMBH)の撮影画像を公開した。本成果はブラックホールの視覚的証拠を
得るとともに、活動銀河核（AGN）のSMBHパラダイムを決定的にするエポックメイキングな
ものであった。しかしながら、EHT画像だけでは降着流やジェットとの関連、高エネルギー
ガンマ線放射との関連などSMBHの性質についてまだまだ未解決な課題が数多い。これらを更に
紐解いていくためには、EHT/ミリ波VLBIの観測を継続するとともに、相補的なセンチ波VLBIや
多波長データを交えた多角的な観測が必要である。本講演ではM87のブラックホールやジェットの
観測について、多波長同時観測や偏光など最近の研究の進展や今後の展望についてお話する。
Facilitator
-Name： 尾崎 忍夫 / Ozaki, Shinobu