5月22日（火）13:30～14:30 理論コロキウム 輪講室
May 22 Tue DTA colloquium Rinko-room
5月23日（水）10:30～12:00 総研大コロキウム 講義室
May 23 Wed SOKENDAI colloquium Lecture Room
5月24日（木）16:00～17:00 国立天文台談話会 大セミナー室
May 24 Thu NAOJ Seminar Large Seminar Room
5月25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
May 25 Fri Solar and Space Plasma Seminar Student Seminar Room, Subaru Bldg.
5月25日（金）16:00～17:00 国立天文台談話会 大セミナー室
May 25 Fri NAOJ Seminar Large Seminar Room
詳細は以下をご覧下さい。
5月22日（火）
- Campus
- Mitaka
- Seminar
- DTA colloquium
- Regularly Scheduled/Sporadic
- Regularly Scheduled
- Date and time
- May 22, 2018, 13:30-14:30
- Place
- Rinko room
- Speaker
- Kazumi Kashiyama
- Affiliation
- University of Tokyo
- Title
- The repeating fast radio burst and the young neutron star model
- Abstract
- Fast radio bursts (FRBs) are enigmatic radio transients with large dispersion measure. There are ~ 30 of FRBs discovered so far and only one of them, FRB121102, repeats. Recently, the host galaxy and persistent radio counterpart have identified for this repeating FRB.
First, I will overview the observational results and the general implications. Then, I will focus on the young neutron star model for FRBs and discuss how one can test the model observationally. In particular, I will discuss the possible connection between FRBs and energetic supernovae. - Facilitator
- -Name：Tomoya Takiwaki
- Comment
- in English
5月23日（水）
- Campus
- Mitaka
- Seminar
- SOKENDAI colloquium
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- May 23, 2018, 10:30 -12:00
- Place
- Lecture Room
- Speaker
- Satoshi Tanioka
- Affiliation
- SOKENDAI 3rd year (D1)(Supervisor: Yoichi Aso,Ryutaro Takahashi,Tomotada Akutsu)
- Title
- bKAGRA Phase 1 From Kamioka with Love
Abstract (if you like):bKAGRA Phase 1 operation was held in April 28th to May 6th. I will report the overview. - Speaker
- zhao yuhang
- Affiliation
- SOKENDAI 3rd year (D1)(Supervisor: Matteo Leonardi,,)
- Title
- status of the frequency dependent squeezing experiment at TAMA
Abstract (if you like):It is expected that the second-generation gravitational wave detectors will be quantum noise limited in the whole detection frequency band. This expectation was partially confirmed by the LIGO-Virgo O1 and O2 runs. KAGRA will be the first 2.5-generation GW detector, and the quantum noise limit is expected to be even more severe than the second-generation detectors. The implement of frequency dependent squeezed(FDS) light source is one of the most promising solutions to this problem. After several years of table top experiments and proof of principle experiments, the implement of squeezing into GW detector is a mature technique. The most studied solution to realize an FDS is the coupling between a frequency independent squeezer to a Fabry-Perot cavity(usually addressed as filter cavity). One of the main parameter of this kind of experiment is the intra-cavity losses per meter of the filter cavity. One solution to mitigate this problem is to use hundred-meter scale filter cavity.The purpose of our experiment, that is in the TAMA300 facility, is to realize FDS with a 300m long filter cavity. The filter cavity is hosted in an arm of the former TAMA300 interferometer. As of today, the filter cavity has been installed and is locked stably with a green field. The characterization work of the filter cavity is ongoing but almost finished. The assembling of the frequency independent squeezer is on going. The next step will be the characterization of the frequency independent squeezing and its injection into the filter cavity.
Please note that the presenter information posted here is not necessarily listed in order of presentation.
- Facilitator
- -Name：Yoshiki Hatta
- Comment
- TV conference system is available connecting from Nobeyama, Hawaii, Mizusawa, and Okayama.
5月24日（木）
- Campus
- Mitaka
- Seminar
- NAOJ seminar
- Regularly Scheduled/Sporadic
- Scheduled
- Date and time
- Thu 24 May. 16:00~17:00
- Place
- Large Seminar Room
- Speaker
- Brian Day (NASA SSERVI) / Emily Law (NASA JPL)
- Title
- ” Mission Planning, Planetary Science, and Public Outreach with NASA’s Solar System Treks”
- Abstract
- NASA’s Solar System Treks Project provides a suit of online, web-based portals for visualizing
and Analyzing planetary surfaces. These portals allow mission planners, planetary scientists, students,
and the general public to explore planetary surfaces as seen through the eyes of many different instruments
aboard a wide range of spacecraft for a growing number of planetary bodies. Portals for the Moon, Mars,
and Vesta are currently online, with new portals now being developed for additional planetary bodies. - Facilitator
- -Name： Matsuda, Yuichi
5月25日（金）
- Campus
- Mitaka
- Seminar
- Solar and Space Plasma Seminar
- Regularly Scheduled/Sporadic
- Regular
- Date and time
- 25 May (Fri), 13:30-15:00
- Place
- Student Seminar Room, Subaru Bldg.
- Speaker
- Satoko Nakamura
- Affiliation
- Kyoto University
- Title
- Time domain simulation of geomagnetically induced current (GIC) flowing in 500 kV power grid in Japan including a three-dimensional ground inhomogeneity
- Abstract
-
We performed time domain simulation of geomagnetically induced currents
(GICs) flowing in the Japanese 500 kV power grid. The three-dimensional distribution of the geomagnetically induced electric field (GIE) was calculated by using the finite-difference time-domain (FDTD) method with a three-dimensional electrical conductivity model constructed from a global relief model and a global map of sediment thickness. First, we imposed a uniform sheet current at 100 km altitude with a sinusoidal perturbation to illuminate the influence of the structured ground conductivity. The simulation result shows that GIE exhibits localized, the uneven distribution that can be attributed to charge accumulation due to the inhomogeneity below the Earth’s surface. The charge accumulation becomes large when the conductivity gradient vector is parallel, or anti-parallel to the incident electric field. For given GIE, we calculated the GICs flowing in a simplified 500 kV power grid network in Japan. The influence of the structured ground conductance on GIC appears to depend on a combination of the location of substations and the direction of the source current. Uneven distribution of the power grid system gives rise to an intensification of the GICs flowing in remote areas where substations/power plants are distributed sparsely.
Secondly, we imposed the equivalent sheet current inferred from the ground magnetic disturbance for the magnetic storm of 27 May 2017 as a source current of the FDTD simulation. The calculated GIC agrees well with the observations at substations around Tokyo when the uneven distribution of GIE is incorporated into the simulation. - Facilitator
- -Name：Shin Toriumi
- Comment
5月25日（金）
- Campus
- Mitaka
- Seminar
- NAOJ seminar
- Regularly Scheduled/Sporadic
- Scheduled
- Date and time
- Fri 25 May. 16:00~17:00
- Place
- Large Seminar Room
- Speaker
- Vikram Ravi (Caltech)
- Title
- “Fast Radio Bursts / 瞬発電波バースト””
- Abstract
- Ten years after their discovery, fundamental questions on the extragalactic fast radio bursts (FRBs) remain open:
(1) what are their progenitors? (2) what is the nature of the medium through which they propagate?
The extreme diversity of the FRB sample in the estimated burst energies, temporal profiles, and polarization properties
makes it difficult to identify individual populations. Similarly, the diversity of propagation signatures (including dispersion,
scattering, and Faraday rotation in intervening inhomogeneous, magnetized plasma) prevents us from identifying
the typical FRB distance scale and progenitor environment. Accurate localization of FRBs, which is technically difficult
when they are first detected, is therefore crucial for further progress. I shall describe efforts at Caltech to construct
a dedicated FRB localization instrument. The successful deployment of a ten-antenna prototype has motivated us to begin
construction of a 110-antenna array (the Deep Synoptic Array; DSA) that will localize >100 FRBs/year to <3 arcseconds.
I will outline the expected outcomes of the DSA, focusing on its potential for the study of physical conditions in the
circum-/intergalactic medium. - Facilitator
- -Name： Matsuda, Yuichi