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2017.9.4-9.8

9月5日(火)13:30~15:00   太陽系小天体セミナー            輪講室
Sep 5 tue              Solar System Minor Body Seminar   Rinko-shitsu,Main Bldg.(East)

9月8日(金)13:30~15:00   太陽天体プラズマセミナー          院生セミナー室
Sep 8 fri              Solar and Space Plasma Seminar    Student Seminar Room, Subaru Bldg.

9月8日(金)16:00~17:00   国立天文台談話会               大セミナー室
Sep 8 fri               NAOJ Seminar                  Large Seminar Room

詳細は以下をご覧下さい。

9月5日(火)

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
9月5日(火曜日)13時30分~15時
場所
輪講室

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

9月8日(金)

Campus
Mitaka
Seminar
Solar and Space Plasma Seminar
Regularly Scheduled/Sporadic
Regular
Date and time
8 September (Fri), 13:30-15:00
Place
Student Seminar Room, Subaru Bldg.
Speaker
Huang Yuwei
Affiliation
Kyoto University
Title
H-alpha absorption profile of erupting filament
Abstract
H-alpha is the most commonly used line in solar prominence and filament observation. The filament eruption event on November 5th 2016 observed by Solar Dynamic Doppler Imager (SDDI), a full solar disk monitor in Hida-observatory, shows that the opacity of H-alpha line decreased rapidly during eruption. Normally this is believed to be a result of ionization of neutral hydrogen. However, as pointed out by Hyder and Lites (1970) and the quantitative non-LTE calculation by Heinzel and Rompolt (1987), Lyman-alpha dimming effects due to apparent Doppler shifts also results in a decreasing of H-alpha opacity.
I will introduce how the H-alpha emergent intensity of a Doppler shifted filament depends on the fine structure of hydrogen atomic model and the incident background radiation using the non-LTE radiative transfer code we developed. The result might offer an interesting point of view on the use of H-alpha line in space weather study.

Facilitator
-Name:Shin Toriumi

Comment
Facilitator
-Name:Shin Toriumi

Comment

9月8日(金)

キャンパス
三鷹
セミナー名
国立天文台談話会
定例・臨時の別
定例
日時
9月8日(金) 16:00-17:00
場所
大セミナー室
講演者
Nick Kaiser
所属
IfA, U. Hawaii
タイトル
Physics of Gravitational Redshifts in Clusters of Galaxies
Abstract
Wojtak, Hansen and Hjorth and others have measured the long-predicted gravitational redshift of light escaping from galaxy clusters using Sloan Digital Sky Survey data. The effect is very small, corresponding to a velocity shift of only ~10 km/s in clusters with internal random motions of order 600 km/s, but the result appears to be fairly robust and seemed to be in good agreement with general relativity predictions and possibly in conflict with some alternative theories. The effect was initially imagined to be a simple astronomical analogue of the famous terrestrial Pound and Rebka experiment that verified Einstein’s theoretical prediction.
However, it was soon realized that the physics of this effect is considerably more complex. As I shall describe, there are actually three other contributions to the measured signal that need to be taken into account. I shall describe recent attempts to model these effects using N-body experiments. I shall also relate the cluster studies to measurements of front-back asymmetry in galaxy clustering on larger scales; the so-called “relativistic” extension to the lowest order redshift space distortion effect, and how these measurements can be used to test of theories of gravity.

連絡先
-名前:矢野 太平

以上

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