Oct 17 Tue 10:00-11:30 太陽系小天体セミナー Zoom
Oct 17 Tue 13:30-14:30 NAOJ Seminar zoom/ Large seminar room in Subaru Building
Oct 18 Wed 10:30-12:00 SOKENDAI Colloquium Hybrid;Large Seminar Room in Subaru Building and Zoom
Oct 18 Wed 14:30-15:30 ALMA-J seminar hybrid (ROOM102 in ALMA building and ZOOM)
Oct 18 Wed 15:30-16:30 NAOJ Science Colloquium The large seminar room / Zoom (hybrid)
詳細は以下をご覧下さい。
=============== October 17 Tue===============
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：10月17日（火曜日）10時00分～11時30分
場所：zoom
講演者：藤原康徳
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
=============== October 17 Tue===============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regularly Scheduled Date and time：2023 Oct 17, 13:30-14:30
Place：zoom/ Large seminar room in Subaru Building
Speaker：Dr,Bruno Dias
Affiliation: President, Sociedad Chilena de Astronomía (SOCHIAS) Professor, Institute of Astrophysics, Department of Physics, Faculty of Exact Sciences, Universidad Andrés Bello (UNAB), Chile
Title: The Chilean Astronomical Society (SOCHIAS)
Abstract: The Chilean Astronomical Society (SOCHIAS) was founded on May 31, 2000 with the goals of boosting Astronomy in Chile, managing the interests of Chilean astronomers, organising scientific meetings, establishing and maintaining contact with organizations in Chile and abroad, and supporting Astronomy education, among other related objectives. In this context, two representatives of the current SOCHIAS board are visiting Japan, and in this presentation we will show some information about SOCHIAS as well as some of our initiatives. We hope to keep and strengthen the relationship among Japanese and Chilean astronomical communities.
Facilitator
-Name：Izumi Takuma
=============== October 18 Wed===============
Campus： Mitaka
Seminar： SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：October 18, 2023 10:30-12:00
Place： hybrid; Large Seminar Room in Subaru Building and Zoom
Speaker: Moka Nishigaki
Affiliation: SOKENDAI 3rd year (D1) (Supervisor: Masami Ouchi, Tadafumi Takata, Kimihiko Nakajima)
Title: Modeling the Mass-Metallicity Relation with Dark Matter Halo Assembly from z=0–10
Speaker: Kuria Watanabe
Affiliation: SOKENDAI 2nd year (M2) (Supervisor: Masami Ouchi, Nozomu Tominaga, Masato Onodera)
Title: The Chemical enrichment and origin of Nitrogen-Rich Galaxies at High Redshift
Facilitator
-Name：Matsuda, Graduate Student Affairs Unit
=============== October 18 Wed===============
Campus: Mitaka
Seminar: ALMA-J seminar
Date and time: Oct 18th (Wed) 14:30-15:30
Place: hybrid (ROOM102 in ALMA building and ZOOM)
Speaker: Pei-Ying Hsieh
Affiliation: NAOJ
Title:The circumnuclear disk revealed by ALMA – environments of star formation in the inner 10 pc of the Galaxy
Abstract:The molecular 2-pc circumnuclear disk (CND) immediately around the Milky Way supermassive black hole (SMBH), SgrA, resembles the “molecular torus” in AGNs, providing a unique opportunity to study SMBH accretion and nuclear star formation at sub-parsec scales. In recent years, I have been studying the key question of how much of the available gas can actually form stars in the environment around Sgr A, and how material is being moved around and accreted in this region. The lifetime of the CND has been a long-standing debate over the past decade. The CND can not live longer than 10^5 years if the gas density is under the tidal threshold of SgrA/nuclear star clusters, thus depleting the source of fuel and star formation. Utilizing the ALMA and various single-dish telescopes, we present CS line maps toward the CND of the Galactic Center. Our primary goal is to resolve the compact structures within the CND and the streamers, in order to understand the stability conditions of molecular cores in the vicinity of Sgr A. Our data provide the first homogeneous high-resolution (1.3″ = 0.05 pc) observations aiming at resolving density and temperature structures. A stability analysis based on the unmagnetized virial theorem including tidal force shows that 84 (+16/-37) % of the total gas mass (2.5X10^4 Msun) is tidally stable, which accounts for the majority of gas mass. Turbulence dominates the internal energy and thereby sets the threshold densities 10-100 times higher than the tidal limit at distance >1.5 pc to Sgr A*, and therefore, inhibits the clouds from collapsing to form stars near the SMBH.
Organizers: Gianni Cataldi , Hiroshi Nagai
=============== October 18 Wed===============
Campus: Mitaka
Seminar: NAOJ Science Colloquium
Date and time: 2023 Oct. 18 (Wed.), 15:30-16:30
Place: The large seminar room / Zoom (hybrid)
Speaker: Yoshiaki Misugi
Affiliation: NAOJ
Title: Evolution of the Angular Momentum of Molecular Cloud Cores in Filamentary Molecular Clouds
Abstract:
The angular momentum of molecular cloud cores plays a key role in the star formation process. However, the evolution of the angular momentum of molecular cloud cores formed in magnetized molecular filaments is still unclear. We perform three-dimensional magnetohydrodynamics simulations to reveal the evolution of the angular momentum of molecular cloud cores formed through filament fragmentation. As a result, we find that the angular momentum decreases by 30% and 50% at the mass scale of
1 Msun in the case of weak and strong magnetic field, respectively. By analyzing the torques exerted on fluid elements at different mass scales, we identify the magnetic tension as the dominant process for angular momentum transfer for mass scales < 3 M sun for the strong magnetic field case. This critical mass scale can be understood semi-analytically as the time scale of magnetic braking. We show that the anisotropy of the angular momentum transfer due to the presence of strong magnetic field changes the resultant angular momentum of the core only by a factor of two. We also find that the distribution of the angle between the direction of the angular momentum and the magnetic field is random even just before the first core formation. Our results also indicate that the variety of the angular momentum of core inherited from the difference of the phase of the initial turbulent velocity field could contribute to the diversity in size and other properties of protoplanetary disks recently reported by observations.
Facilitator
-Name: Kanji Mori
Comment: English