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June 14 Tue 10:00~11:30 太陽系小天体セミナー Solar System Minor Body Seminar zoom

June 15 Wed 10:30~12:00 SOKENDAI Colloquium  zoom

June 15 Wed 14:30~15:30  ALMA-J Seminar zoom

June 15 Wed 15:30~17:00  NAOJ Science Colloquium    zoom






Seminar:SOKENDAI Colloquium
Regularly Scheduled/Sporadic:Regular
Date and time:June 15th, 2022 10:30-12:00

Speaker 1: Kanako Sugimori
Affiliation: SOKENDAI 3rd year (D1) (Supervisor: Masayuki Tanaka, Masato Onodera, Yuichi Matsuda)
Title: Study of the star formation histories from SEDs at 0 < z < 5

Speaker 2: Hideaki Takemura
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Fumitaka Nakamura, Tomoya Hirota, Akimasa Kataoka)
Title: Dense core survey and core mass function with 3D MHD simulation data

-Name:Matsuda, Graduate Student Affairs Unit


Campus; Mitaka
Seminar; ALMA-J seminar
Regularly Scheduled/Sporadic; Every Wednesday
Date and Time; 2022 June 15 14:30-15:30
Place; Zoom
Speaker; Kazuki Tokuda
Affiliation; Kyushu University/NAOJ
Title: ALMA resolved views of molecular filaments/clumps in the Large Magellanic Cloud: A possible gas flow penetrating one of the most massive protocluster systems in the Local Group
Abstract: We present spatially resolved molecular filaments in the high-mass star-forming regions N159E-Papillon, W-South, and W-North in the Large Magellanic Cloud (LMC). Our ALMA observations in CO isotopes revealed remarkable hub-filament systems with a typical width of 0.1 pc in 13CO, where a young HII region (the Papillon Nebula) and an embedded high-mass protostar along with six protostellar outflows have been newly discovered/resolved (Fukui+19; Tokuda+19). All these young protostellar objects have an age of 10^4 to 10^5 yrs, whereas they are scattered over a distance spanning ~50 pc.
The most massive clump in the observed regions, N159W-North MMS-2, shows an especially massive/dense nature whose total H_2 mass and peak column density are ~10^M_sun and ~10^24 cm^-2, respectively, and harbors massive (~100 M_sun) starless core candidates identified as its internal substructures (Tokuda+22). The CO (1-0) data set with a larger field of view reveals a conical-shaped, ~30 pc long complex extending toward the northern direction. These features indicate that a large-scale gas compression event may have produced the massive star-forming complex. Based on the striking similarity between the N159W-North complex and the other two regions, we propose a teardrops inflow model that explains the synchronized, extreme star formation across ~50 pc, including one of the most massive protocluster clumps in the Local Group. The proposed flow, driven by the tidal interaction between the LMC and SMC, explains the formation of the hub-multi-filament system as shown by recent MHD simulations, which predict the synchronized triggered formation of the most massive star at the hub and additional star formation along the dense filaments/clumps.

Daisuke Iono, Andrea Silva


Seminar:NAOJ Science Colloquium
Regularly Scheduled/Sporadic:Every Wednesday
Date and time:2022 June 15, 15:30-17:00
Speaker:Yuhiko Aoyama
Affiliation:Tsinghua University
Title:Hydrogen line emission from accreting gas-giant planets
Abstract:Gas giant planets such as Jupiter are mainly composed of hydrogen gas. They form in the circum-stellar gaseous disk (so-called protoplanetary disk) by gathering its surrounding gas. Recent instruments have successfully detected forming giant planets embedded in the protoplanetary disk by direct imaging. Particularly, the detection of hydrogen lines including H-alpha (Balmer-alpha) is a key to understanding their formation. Hydrogen lines require hot gas of ~10^4 K. However, at the hydrogen line emitting planets, the photospheric temperature is estimated as a few thousand K by IR observation. Therefore, hydrogen lines are thought to come from the gas accretion towards the forming planets.
In this talk, I will show our numerical model of hydrogen line emission at the accretion shock on the planetary surface. We confirmed the shock emission can reproduce the observation and estimated their accretion properties such as mass accretion rate by the flux and spectral profile of the observed hydrogen lines. Then, I will introduce the competitive line emission model of “magnetospheric accretion column” and how we can distinguish the emission mechanism with some future observations.
-Name:Akimasa Kataoka

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