Feb. 20 Mon 16:00-17:00 NAOJ Seminar Zoom/Lecture Room(hybrid)
Feb. 21 Tue 10:00-11:30 太陽系小天体セミナー Zoom
Feb. 22 Wed 14:30-15:30 ALMA-J Seminar Zoom/ALMA building #102 (hybrid)
Feb. 22 Wed 15:30-17:00 NAOJ Science Colloquium Zoom / Instrument Development Bldg. 3 (hybrid)
詳細は下記からご覧ください。
=============== Feb 20 Mon ===============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Sporadic
Date and time：2023 February 20, 16:00-17:00
Place： Zoom/Lecture Room(hybrid)
Speaker: Geoffrey Bower
Affiliation：EHT Collaboration, ASIAA and University of Hawaii
Title：Imaging Black Holes with the Event Horizon Telescope
Abstract:The Event Horizon Telescope (EHT) is a global submillimeter-wavelength very long baseline array that produces the highest angular resolution images of black holes. The EHT Collaboration has produced images of two black holes, the supermassive black hole in the elliptical galaxy M87 and the Galactic Center black hole, SgrA*. In this talk, I will describe the techniques and technology behind these measurements. Both images have a ring-like morphology consistent with predictions of general relativity and the Kerr metric. Comparison with an unprecedented library of GRMHD simulations provides insights on the accretion and outflow properties. These results confirm that the gravitational lensing feature is a universal property of black holes, establishes the consistency of general relativity over three orders of magnitude in mass, and opens the door for future tests of gravitational physics, accretion, and jet formation.
Facilitator
-Name：Fujii, Yuka
=============== Feb 21 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：2月21日（火曜日）10時00分～11時30分
場所：zoom
講演者：Masateru Ishiguro
所属：Seoul National University, South Korea
タイトル：Consideration of Phaethon
Abstract：Phaethon, the target asteroid of the DESTINY+ mission, has
shown various interesting aspects (dust ejections near perihelion,
moderately-high albedo, extremely high polarization and its
inhomogeneity, presence of Geminids meteor shower, etc.). In this talk,
I will discuss the phenomena that might have occurred at Phaethon within
the past 10,000 years based on research conducted with my graduate
students at Seoul National University.
Collaborators (Yoonsoo P. Bach, Hangbin Jo, Jooyeon Geem, Sunho Jin, and
Bumhoo Lim)
世話人の連絡先
名前：渡部潤一
=============== Feb 22 Wed ===============
Campus：Mitaka,
Seminar：ALMA-J seminar
Regularly Scheduled/Sporadic： Every Wednesday
Date and time： February 22, 2023 (Wed), 14:30 – 15:30
Place： ALMA building #102 / Zoom (hybrid)
Speaker: Asako Sato
Affiliation: Kyushu University
Title: ALMA fragmented source and outflow identifications in OMC-2/FIR 3, FIR 4, and FIR 5
Abstract:
The Orion Molecular Cloud 2 (OMC-2) in the northern part of Orion A (d = 400 pc) is known as an embedded protocluster containing a large number of infrared sources (400 pc^{-2}; Lada & Lada 2003). In the OMC-2, fifteen young sources are clustering within three millimeter sources, FIR 3, FIR 4, and FIR 5 (Chini et al. 1997, Farlan et al. 2016). This talk will introduce the results and discussions presented by Sato et al. (2023). Using the Atacama Large Millimeter/submillimeter Array (ALMA), we performed mosaic observations toward FIR3, FIR4, and FIR5, covering an area of 0.35 pc x 0.23 pc (~2’.9 × 1’.9), in the 1.3 mm continuum, CO (J = 2–1) line, and SiO (J = 5–4) line emissions. We identified 51 continuum sources, 36 of which are newly identified in Sato et al. (2023). Their dust masses, projected sizes, and H2 gas number densities are estimated to be 3.8 × 10^{-5} — 1.1 × 10^{-2} Msun, 290 — 2000 au, and 6.4 × 10^6 — 3.3 × 10^8 cm^{-3}, respectively. The results of a Jeans analysis showed that, among the identified continuum sources, ~80% of the protostellar sources and ~15% of the prestellar sources are self-gravitationally bound. We identified 12 molecular outflows traced in the CO (J = 2–1) emission, six of which are newly detected. We identified shocked gas originating from outflows and other shocked regions traced by the SiO (J = 5–4) emission in this region. These results provide direct evidence of an interaction between a dust condensation, FIR 4, and an energetic outflow driven by HOPS-370 within FIR 3. In this talk, I discuss how identified molecular outflows interact with other cluster members, and how the interaction might affect the star formation within the embedded cluster by timescale comparison.
Facilitator: Shun Ishii, Jorge Zavala
=============== Feb 22 Wed ===============
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday
Date and time：2023 Feb. 22, 15:30-17:00
Place：zoom / Instrument Development Bldg. 3 (hybrid)
Speaker：Hiroko Okada
Affiliation：NAOJ (M2)
Title：TBD
Abstract：TBD
Speaker：Kaho Morii
Affiliation：NAOJ (D1)
Title：Dense Cores Embedded in 70µm-dark High-mass Clumps: CMF and Fragmentation
Abstract：The very early evolutionary stage of high-mass star and cluster formation is a key phase for understanding how the progenitors of stars form and evolve. We have conducted the ALMA Survey of 70 µm Dark High-mass Clumps in Early Stages (ASHES) toward thirty-nine cold regions with massive, dense molecular gas, which are thought to be the ideal sites to investigate the early phase of high-mass star formation. The high-resolution (~1.”2) and high-sensitivity observations mosaicked by ALMA succeed in revealing the internal structure of infrared-dark clouds and the unprecedented amount of 839 cores. This is the largest sample of cores in IRDCs observed with ALMA so far. In this talk, I will present prestellar core mass function (CMF) with the comparison with protostellar CMF and Salpeter’s IMF, and the fragmentation properties compared with Jeans fragmentation.
Facilitator
-Name：Akimasa Kataoka
-Comment：in English