July 26 Wed 10:30-12:00 SOKENDAI Colloquium Zoom / the large seminar room (hybrid)
July 26 Wed 13:30-15:00 Solar and Space Plasma Seminar Zoom
July 26 Wed 15:00-16:00 NAOJ Science Colloquium Zoom / Large Seminar Room (hybrid)
July 27 Thu 16:00-17:00 NAOJ Seminar Zoom / the large seminar room (hybrid)
July 28 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。
=============== July 26 Wed===============
Campus：Mitaka
Seminar：SOKENDAI Colloquium
Regularly Scheduled/Sporadic：Regular
Date and time：July 26, 2023 10:30-12:00
Place：Large Seminar Room in Subaru Building and Zoom
Speaker: Ryota Ichimura
Affiliation: SOKENDAI 3re year (D1) (Supervisor: Hideko Nomura, Akimasa Kataoka, Nanase Harada)
Title: Gas-Grain Model for Carbon Isotope Fractionation of COMs in Star-Forming Cores
Speaker: Umi Kobayashi
Affiliation: SOKENDAI 5th year (D3) (Supervisor: Masayuki Tanaka, Koichiro Nakanishi, Masatoshi Imanishi)
Title: TBA
Facilitator
-Name：Matsuda, Graduate Student Affairs Unit
=============== July 26 Wed===============
Campus： Mitaka
Seminar： Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic： Scheduled
Date and time：26th July (Wednesday), 13:30-15:00
Place： zoom
Speaker：Dr. Tomoko Kawate
Title :An Inductively Coupled Plasma System for Investigating Spectropolarimetric Responses of Solar Plasmas to Anisotropic Fields
Abstract:
High precision measurements and accurate modeling of atomic polarization under three-dimensional radiation transfer are crucial to understand the structures of magnetized solar plasmas.
To develop and validate spectropolarimetric measurements and analyses, we set up an inductively coupled plasma (ICP) generator designed especially for ∼ 1-eV plasmas
interacting with radiation and weak magnetic fields. The device was put in front of the focal plane of the Horizontal Spectrograph of the Domeless Solar Telescope
at Hida Observatory of Kyoto University. In helium discharges, the typical electron temperature, electron density, and helium column density of the ICP are comparable
values to those of solar prominences, and the direct comparison of spectra shows almost the same opacity at He I 1083 nm. Magnetic and radiation fields were introduced to the ICP,
and the system successfully reproduced reasonable spectropolarimetric signals as compared with those from the solar prominences.
Facilitator
-Name：Yusuke Kawabata
=============== July 26 Wed===============
Campus：Mitaka
Seminar：NAOJ Science Colloquium
Regularly Scheduled/Sporadic：Every Wednesday
Date and time：2023 July 26, 15:00-16:00
Place：Zoom / the large seminar room (hybrid)
Speaker：Toshiki Sato
Affiliation：Meiji University
Title：Exploring the interior of supernovae and their progenitors using
supernova remnants
Abstract：
It is difficult to observe the physical conditions inside the
supernova or its progenitor star immediately before and after the
supernova explosion, where the important physics of stellar evolution
and supernova explosions are concentrated. Our research focuses on the
X-ray study of “supernova remnants” in order to extract the internal
information at the moment of a star’s death. The uniqueness of supernova
remnants is that it is possible to observe different elements
synthesized inside stars and supernovae, and to infer the internal
physical states (electron fraction, density structure, etc.) from the
amount of elements. In this colloquium, based on our recent X-ray
research, we would like to discuss what kind of information can be
obtained from supernova remnant observations, and what we can expect
from future research on supernovae and their progenitors.
Facilitator
-Name：Koh Takahashi
Comment：English
=============== July 27 Thu===============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Spordiac
Date and time：2023 July 27, 16:00-17:00
Place：Zoom / the large seminar room (hybrid)
Speaker：Achamveedu, Gopakumar
Affiliation：Tata Institute of Fundamental Research, India
Title: Promise of persistent multi-messenger GW astronomy with sources like Blazar OJ287
Abstract：
Recent coordinated observations and interpretations of disparate `messenger’ signals from GW170817-GRB170817AEM170817
has inaugurated the era of multi-messenger transient gravitational wave (GW) astronomy.
I will argue that the bright Blazar OJ 287 should allow us to pursue persistent multi-messenger GW
astronomy during the era of Square Kilometer Array.This is mainly due to the several successful multi-wavelength
observational campaigns that allowed us to establish the presence of a spinning supermassive black hole
binary that spirals in due to the emission of nano-Hertz GWs in the central engine of a unique blazar OJ287.
Our on-going efforts, relevant to the EHT/GMVA consortia and the International Pulsar Timing Array consortium which
aims to detect GWs from such massive BH systems in the coming years, will be also listed.
Facilitator
-Name：Fumitaka Nakamura
=============== July 28 Fri===============
Campus：Mitaka
Seminar：NAOJ Seminar
Regularly Scheduled/Sporadic：Regular
Date and time：2023 July 28, 16:00-17:00
Place：Zoom / the large seminar room (hybrid)
Speaker：Samuel Totorica
Affiliation：Division of Science, NAOJ
Title: Magnetic reconnection in large-scale astrophysical systems
Abstract：
Magnetic reconnection is an important source of energetic particles in systems ranging from astrophysical compact objects to laboratory fusion devices.
The large separation of spatiotemporal scales involved in reconnection makes it critical to determine the minimum physical models containing
the necessary physics for modeling particle acceleration. In this presentation, I will discuss two methods for bridging
the gap between macro- and micro-scales in reconnection using fully kinetic particle-in-cell simulations. First, we study the onset of substorms
in Earth’s magnetosphere using exact kinetic equilibria extending from near-Earth into the distant magnetotail.
Using two- and three-dimensional particle-in-cell simulations, we study the onset of reconnection, the disruption of reconnection fronts,
and their roles in producing nonthermal particles observed by satellite measurements. Second, I will discuss a novel method for
separating kinetic and fluid effects by exactly calculating the ideal and nonideal magnetohydrodynamic electric fields within fully kinetic simulations.
Applying this to the relativistically magnetized conditions of astrophysical compact objects, we determine the critical role
of the nonideal electric field during the early stage of particle acceleration known as injection. These results have critical implications for
nonthermal emissions from high-energy astrophysical objects, and the novel analysis method can be applied more broadly to give new insight into a wide range of processes in plasma physics.
Facilitator
-Name：Fumitaka Nakamura