10月9日（火）13:30～15:00 太陽系小天体セミナー 南棟２階会議室
Oct 9 Tue Solar System Minor Body Seminar Conference Room, South Bldg.2F
10月10日（水）13：30～15：00 太陽天体プラズマセミナー 院生セミナー室
Oct 10 Wed Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
10月11日（木）14：00～15：00 理論コロキウム 開発棟３号館３階会議室
Oct 11 Thu DTA colloquium Conference room, Instrument Development Bldg. 3 3F
10月12日（金）16：00～17：00 国立天文台談話会 すばる棟 大セミナー室
Oct 12 Fri NAOJ Seminar Large Seminar Room
詳細は以下をご覧下さい。
10月9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
- 10月9日（火曜日）13時30分～15時
- 場所
- 南棟２階会議室
- 講演者
- 大坪貴文
- 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
10月10日（水）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Sporadic
- Date and time
- 10 October (Wed), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Petr Heinzel
- Affiliation
- Academy of Sciences of Czech Republic
- Title
- White-light flares and stellar superflares
- Abstract
-
I will present an overview of observations and modeling of the so-called solar white-light flares (WLF), extending this also to UV continua detected from space. There is a continuing discussion about relevant physical mechanisms which are responsible for solar and stellar WLFs and the main problem is to distinguish between photospheric and chromospheric contributions to the spectral intensity. On the other hand, a purely chromospheric component can be well separated in limb flares where we detected the WLF emission just above the solar limb and this corresponds to the chromospheric heights – I will present also some recent results of numerical RHD simulations with the Flarix code.
Finally, it appeared that also the whole flare loops, both cool (misleadingly called ‘post’ flare loops), as well hot ones, emit in the visible continuum and this was detected by SDO/HMI instrument at loop heights. This latter issue is directly related to a novel idea that also stellar superflares may be partially due to WL loop emission (Heinzel & Shibata 2018). - Facilitator
- -Name：Shin Toriumi
- Comment
10月11日（木）
- Campus
- Mitaka
- Seminar
- DTA colloquium
- Regularly Scheduled/Sporadic
- Sporadic
- Date and time
- Oct. 11, 2018, 14:00-15:00
- Place
- Conference room, Instrument Development Bldg. 3 3F
- Speaker
- Hector O. Silva
- Affiliation
- Montana State University
- Title
- Illuminating the strong-field regime of gravity
- Abstract
- Observation of the x-ray pulse profile emitted by hotspots on the surface of neutron stars offers a unique tool to measure the properties of these objects, including their masses and radii. The x-ray emission takes place at the star’s surface, where the gravitational field is strong, making these observations an incise probe into the spacetime curvature generated by these stars. In this presentation, I will discuss how general relativity plays a key role in the accurate modelling of pulse profiles and the prospects for testing Einstein’s theory – and some of its contenders – using these observations.
- Speaker
- George Pappas
- Affiliation
- Sapienza University of Rome
- Title
- Testing the Kerr hypothesis with QNMs and ringdowns.
- Abstract
- The Kerr spacetime that describes all rotating black holes is one of the most important solutions of general relativity. The theoretical and astrophysical significance of this solution cannot be underestimated. For this reason it is of analogous importance to thoroughly test whether the objects that we have identified as the astrophysical incarnations of Kerr black holes are actually that or some alternative exotic compact object that simply mimics aspects of their behaviour. With the advent of gravitational wave astronomy, this is possible by observing the inspiral, merger, and ringdown of binary systems. This talk will discuss some ways that we can use to test for these impostors.
- Facilitator
- -Name：Tomoya Takiwaki
- Comment
- in English
10月12日（金）
- Campus
- Mitaka
- Seminar
- NAOJ seminar
- Regularly Scheduled/Sporadic
- Scheduled
- Date and time
- Friday, Oct 12 16:00-17:00
- Place
- Large Seminar Room
- Speaker
- Douglas Gough
- Affiliation
- IoA, University of Cambridge
- Title
- “The rotational dynamics of the Sun”
- Abstract
-
The Sun condensed from the interstellar medium 4.6 Gy ago, preserving, in the initial
stages, a memory of the galactic vorticity and magnetic field. How it subsequently
divested itself of almost all of that is one of the most important questions in
asterophysics, yet remains far from being answered. Helioseismology has transformed
our appreciation of the relevant issues, partly by eliminating many of the early
conjectures regarding the Sun’s present kinematical state. From our knowledge so
gained of both the internal angular velocity and the density stratification, multipole
moments of the external gravitational potential have been determined, providing a
crucial test, in the weak-field limit, of General Relativity. A shear layer at the
base of the convection zone, known as the tachocline, exists by dint of the dipolar
vestige of the interior magnetic field, and has probably caused the magnetic axis to
be inclined from the axis of rotation. I propose that the outcome induces a signature
in the geomagnetic field, providing a precise estimate of the rotation rate of the
Sun’s radiative interior. These matters are no doubt of interest to astronomers who
adopt the Sun as a prototype of cool main-sequence stars, but, more importantly in
some minds, provide valuable information about the basic physics at play. - Facilitator
- -Name： Nakaya, Hidehiko