May 24 Wed 10:30-12:00 SOKENDAI Colloquium Zoom / the large seminar room (hybrid)
May 24 Wed 15:30-17:00 NAOJ Science Colloquium Zoom / the large seminar room (hybrid)
May 26 Fri 13:30-14:30 ATCセミナー Zoom / the large seminar room (hybrid)
May 26 Fri 16:00-17:00 NAOJ Seminar Zoom / the large seminar room (hybrid)
詳細は下記からご覧ください。
=============== May 24 Wed===============
Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：May 24, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom
Speaker: Masato Sato
Affiliation: SOKENDAI 4th year (D2) (Supervisor: Nozomu Tominaga, Tomoya Takiwaki, Takashi Moriya)
Title: Light curve of electron capture and Fe core collapse supernovae: The diagnostic method of electron capture supernovae
Speaker : Takaho Masai
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Alvaro Gonzalez, Yoshinori Uzawa, Takafumi Kojima)
Title: Exploring the Application of 3D Printed Magic Tee Waveguide Junctions for Millimeter Wave Radio Receivers
Facilitator
-Name：Matsuda, Graduate Student Affairs Unit
=============== May 24 Wed===============
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday
Date and time：2023 May 24, 15:30-17:00
Place：zoom / the large seminar room (hybrid)
Speaker：Rikuto Omae
Affiliation：NAOJ (D3)
Title：Observation of magnetic fields in lensing galaxies using radio
polarization data
Abstract：External galaxies often intervene on background radio sources
such as quasars and radio galaxies. Linear polarization of the
background emission is depolarized by the Faraday rotation of
inhomogeneous magnetized plasma of the intervening galaxies. Exploring
the depolarizing intervening galaxies can be a powerful tool for
investigating the cosmological evolution of the galactic magnetic field.
Recently, Mao et al. (2017) detected coherent μG magnetic fields in the
lensing disk galaxy by exploiting the scenario where the polarized radio
emission from a background source is gravitationally lensed by an
intervening galaxy using broadband radio polarization data. The method
is based on the difference in Faraday depths, where the background
source emission passes through different positions of the intervening
galaxies due to the gravitational lensing effect. Using a galactic
magnetic field model, we investigate how background polarized sources
are observed due to the gravitational lensing effects of intervening
galaxies. We will also discuss how this can be observed and applied in
real data using the SKA predecessor.
Speaker：Yuta Tashima
Affiliation：NAOJ (D3)
Title：Elucidation of galactic magnetic field structure by
pseudo-observation based on SPH simulation
Abstract：It is known that the average magnetic field strength of spiral
galaxies is about a few micro G, but the structure of the global field
has remained unclear parts. Since observables are integral values
along the line of sight, it is difficult to obtain a three-dimensional
structure. Therefore, we aim to clarify the relationship between the
radiation field and the spatial distribution of physical quantities
through pseudo-observations using global simulation results. Our
previous research adopted the galactic gaseous disk model calculated by
MHD simulation, whose calculation assumed a static galactic stellar
potential and ignored a cooling effect.
Therefore, we thought more realistic results could be obtained using SPH
simulation data that considers potential changes due to stellar motion.
We calculated the magnetic field using the induction equation from the
SPH simulation results and performed a pseudo-observation.
As a result, we found that the magnetic field is strongly amplified
around the wind blowing from the end of the bar. In the case of an
edge-on view, pseudo-observation results can reproduce the X-shape
structure often observed in edge-on starburst galaxies. However, the
SPH case did not reproduce the magnetic spiral arm structure. This is
because SPH solves the induction equation independently, and the result
shows the importance of feedback to the motion of the magnetic field.
Facilitator
-Name：Yuka Fujii
=============== May 26 Fri===============
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：5月26日（金曜日）13時30分～14時30分
場所：大セミナー室 + Zoom
講演者： 佐藤 洋一 氏
所属：宇宙航空研究開発機構（JAXA）研究開発部門 第二研究ユニット
タイトル：高感度観測ミッションに必要な宇宙用極低温冷凍機の開発と将来に向けた研究状況
Abstract：
JAXA研究開発部門の佐藤洋一と申します。ATCセミナーでの発表の機会をいただきありがとうございます。
本講演では、地球観測・天文観測などの高感度観測ミッションにおいて用いられる宇宙用極低温冷凍機について、
観測装置の冷却システムにおける位置づけやこれまでに達成された冷却性能や開発試験の結果、
将来ミッションに向けた長寿命化に関する研究状況について発表させていただきます。
また、冒頭では、私の自己紹介に加えて，所属する研究開発部門研究第二ユニットの紹介と
職員のキャリアパスについて自身の経験を踏まえてお話しさせていただきます。
世話人の連絡先
-名前：永井 誠
備考：日本語での講演。
=============== May 26 Fri===============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regularly Scheduled
Date and time：2023 May 26, 16:00-17:00
Place： Zoom/Large Seminar Room(hybrid)
Speaker:Koh Takahashi
Affiliation: Division of Science NAOJ
Title:Open Questions in Massive-star Evolution
Abstract：Massive stars are fundamental drivers of the evolution of the universe, impacting their surrounding environment by emitting intense photon radiation and powerful stellar winds throughout their lives. In this talk, I will first summarize our understanding of the basic issues involved in massive star evolution, then, important open questions that need to be resolved by future research, such as the effects of binary stars and magnetic fields, will be reviewed. I believe that as many different perspectives as possible will be effective in solving the problems.
I welcome the participation of experts in various fields at NAOJ.
Facilitator
-Name：Ozaki, Shinobu