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中央研究院天文及天文物理研究所
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Activity > Colloquium

Colloquiums and Seminars(2020)

ASIAA Colloquium is usually held on Wednesdays at 2:20-3:20 pm in Room 1203 of the Astronomy-Mathematics Building, NTU. All scientists are welcome to attend. Seminars on more specialized topics are also held on a regular basis.

The ASIAA-NTU joint colloquium series aims to bring to the physics/astronomy/cosmology community in ASIAA/NTU world renown researchers who will talk about the forefront development of physical sciences.

Contact: Colloquium Committee (talks_replace2@_asiaa.sinica.edu.tw)

NEXT Colloquium: 2020-02-12 Wed 14:20~15:20 [R1203]
Speaker:Po-Yu Chang
No. Time/Place Speaker Topic / Abstract
download PDF: download talk PDF file
12020-07-08 Wed
14:20~15:20
R1203
Emeric Le Floc'h
[CEA Saclay]
Colloquium
22020-04-29 Wed
14:20~15:20
R1203
Hidetoshi Sano
[NAOJ]
Colloquium
32020-04-22 Wed
14:20~15:20
R1203
Denis Burgarella
[Laboratoire d'Astrophysique de Marseille]
Colloquium
42020-04-01 Wed
14:20~15:20
R1203
Hajime Sotani
[RIKEN]
Colloquium
52020-03-04 Wed
14:20~15:20
R1203
Ray Lin
[NTHU]
Colloquium
62020-02-26 Wed
14:20~15:20
R1203
Nanda Kumar
[Centro de Astrofísica da Universidade do Porto]
Colloquium
72020-02-25 Tue
14:20~15:20
R1203
Takuya Inoue
[Doshisha University]
Seminar
82020-02-18 Tue
14:20~15:20
R1203
Seongjoong Kim
[Tokyo Institute of Technology]
Seminar
92020-02-12 Wed
14:20~15:20
R1203
Po-Yu Chang
[National Cheng Kung University, Institute of Space and Plasma Sciences]
Colloquium
102020-01-15 Wed
14:40~15:40
R1203
Jongho Park
[ASIAA]
Colloquium
Acceleration and Collimation of the M87 Jet
Abstract

It is widely accepted that relativistic jets in AGNs are accelerated by strong magnetic fields. The magnetohydrodynamic (MHD) models of jet acceleration predict that (i) jet is gradually collimated by the pressure of an external medium confining the jet and (ii) jet collimation and acceleration occur simultaneously. Indeed, systematic collimation has been revealed in the jet of M87 inside the Bondi radius by many recent very long baseline interferometry observations. However, both the nature of the external confining medium and the presence of gradual jet acceleration in the jet collimation zone have not been well constrained by observations. In the first part of my talk, I briefly introduce our recent study of Faraday rotation in the M87 jet, where information on the external medium is imprinted. We found that the magnitude of the Faraday rotation measure systematically decreases with increasing distance from the black hole in the jet collimation zone. Our data is consistent with a picture that substantial winds, non-relativistic un-collimated gas outflows launched from hot accretion flows, confine the jet, resulting in the observed jet collimation. In the second part, I present the results of our recent kinematic analysis of the high-cadence monitoring data observed with the East Asian VLBI Network (EAVN) and of the Very Long Baseline Array (VLBA) archival data. We found that the jet is gradually accelerated from non-relativistic to relativistic speeds over a broad distance range that coincides with the jet collimation zone, which is in good agreement with the prediction of the MHD models.

112020-01-08 Wed
14:20~15:20
R1203
Daichi Hiramatsu
[UCSB]
Colloquium
Recent Advancements in Core-collapse Supernova Observation Through the Global Supernova Project
Abstract

Supernovae are among the most influential events in every astrophysical scale. New wide-field and high-cadence transient surveys enable us to watch supernovae from the moment of explosion. Paired with rapid and continuous monitoring facilities, these observations reveal unprecedented features that bridge our understanding of their progenitor systems to explosion mechanisms. From the discovery to follow-up, the Global Supernova Project is a world-wide collaboration of +150 supernova observers and theorists facilitated with the Las Cumbres Observatory and various other ground and space telescopes. In this talk, I will highlight the recent advancements in core-collapse supernova observation, especially in the context of the Global Supernova Project.

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