May 18 Tue 10:00～11:30 太陽系小天体セミナー / Solar System Minor Body Seminar zoom
May 18 Tue 9:00～9:50 Preliminary Defense for the doctoral thesis of the Department of Astronomical Science, SOKENDAI zoom
May 19 Wed 15:00～16:00 ALMA-J seminar zoom
May 19 Wed 15:30～17:00 NAOJ Science Colloquium zoom
詳細は以下をご覧下さい
5月18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：5月18日（火曜日）10時00分～11時30分
場所：zoom
講演者：古荘玲子
世話人の連絡先
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
5月18日（水）
Campus：Mitaka
Seminar：Preliminary Defense for the doctoral thesis of the Department of Astronomical Science, SOKENDAI
Regularly Scheduled/Sporadic：Sporadic
Date and time：18 May, 9:00～9:50（JST）
Place：Zoom
Speaker：Cui, Yuzhu
Affiliation：Department of Astronomical Science, The Graduate University for Advanced Studies, SOKENDAI
Title：Probing the formation regions of relativistic jets in nearby active galactic nuclei M87 with the East Asian VLBI Network
Facilitator
-Name：Hideyuki Kobayashi,
Yumiko Omura (Graduate Student Affairs Unit)
5月19日（水）
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday
Date and time：2021 May 19, 15:30-17:00
Place：zoom
Speaker：Yuta Tashima
Affiliation：new member, D1
Title：TBD
Abstract：TBD
Speaker：Rikuto Omae
Affiliation：new member, D1
Title：Effects of Depolarizing Intervening Galaxies on Background Radio Emission
Abstract：External galaxies often intervene in front of background radio sources such as quasars and radio galaxies. Such intervening galaxies affect observed polarization properties of the sources due to magnetic fields in the galaxies. Exploring the depolarizing intervening galaxies (DINGs) is thus a powerful tool to investigate the cosmological evolution of galactic magnetic field. In this talk, we focus on the global disk magnetic field, a primary component of galactic magnetic fields, and investigate the effects of DINGs on background radio emission using a simple model. We find that the degree of depolarization significantly depends on the inclination angle of the DING. When the DING is close to the edge-on view, depending on the angular size of background source relative to the DING, the Faraday dispersion function exhibits two components due mainly to the filling factor of the DING. Monte Carlo simulations suggest that DING’s contribution to the observed RM depends on the DING’s redshift.
Facilitator
-Name：Akimasa Kataoka
5月19日（水）
Campus: Mitaka
Seminar: ALMA-J seminar
Regularly Scheduled/Sporadic: Every Wednesday
Date and Time: 2021 May. 19 15:00-16:00
Place: Zoom
Speaker：Haruka Sakemi (NAOJ/JSPS)
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. In this presentation, I will review my research and future plan.
Facilitator: Yuichi Matsuda, Yusuke Miyamoto