[Speaker 1]
Junya Sakurai
[Title]
Measurement of Mass Distribution of Dark Matter Using Weak Gravitational Lensing
[Abstract]
According to the observational results from high-z supernovae and CMB, the universe almost consists of the dark matter and the dark energy.
Unfortunately, these components haven’t entirely understood yet. To understand these unknown objects, some techniques are proposed. One of these techniques is the gravitational lensing. The gravitational lensing is the effect that the shape of the background galaxy is distorted by the foreground object. We can estimate the mass
distribution of the foreground object from the distortion of the background galaxy. Even if the foreground object is the dark matter, we can estimate the mass distribution of the dark matter. In my talk,
I present the gravitational lensing of the basis of this technique.
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[Speaker 2]
Rhythm Shimakawa
[Title]
Nature and Nurture Effects on the Formation and Evolution of Cluster Galaxies
[Abstract]
In low-redshift clusters, most galaxies appear to be quiescent.
These galaxies tend to be elliptical or S0 galaxies, which constitute conspicuous red-sequence on the color-magnitude diagrams.
In contrast, in high-redshift proto-clusers, galaxies tend to have complicated morphologies and high star-formation rates (SFRs) of 100s $M_\odot/yr$.
Such truncation in star formation activities can be caused by “nature” effects, i.e.\ accelerated galaxy formation in dense environments, and/or by “nurture” effects, i.e.\ galaxy-galaxy interactions/mergers and gas-stripping (e.g.\ Kodama et al. 2001).
Recent works (Daddi et al 2007; Mannucci et al. 2010) have presented double (main and sub) sequences of star forming galaxies on the SFR versus gas-mass plane, and a fundamental metallicity relation (FMR) where gaseous metallicity of star forming galaxies in the SDSS are determined as a function of stellar mass and SFR, both of which describe the modes of star formation and the evolutionary stages of galaxies.
Motivated by these observational phenomena, we now aim to explore these relationships (main/sub sequenes and FMR) in clusters/proto-clusters based on near-infrared specroscopy (FMOS/MOIRCS on Subaru) and ALMA observations (Mahalo-Subaru and Gracias-ALMA projects).
By comparing these relationships in clusters with the field counterparts, we will quantify the roles of environments to shape galaxies, and thus understand the origin of environmentally dependent galaxy formation and evolution.
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[Speaker 3]
Shogo Ishikawa
[Title]
the determination of the masses of dark matter halos by clustering properties of sBzK galaxies
[Abstract]
The existence of vast “dark matter halos” around luminous galaxies is strongly implied by some evidence. It is extremely difficult, however, to measure the masses of high-redshift galaxies’ dark matter halos.
One method to quantify them is to measure the amplitude of galaxy clustering, since CDM models predict a monotonic correlation that more massive halos are clustered more strongly. Measuring galaxy clustering requires a large sample from wide area.However, it is still hard to do this at z~2, where BzK color selection can allow us to accumulate larger samples, due to a lack of combination of wide optical and NIR data. I will show our challenge to overcome this difficulty.
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[Speaker 1]
Zhao Zhengshi
[Title]
Spectroscopy of blue straggler stars in Galactic open cluster NGC 2682 (M67)
[Abstract]
In this presentation, we report spectroscopic analysis of eight blue straggler stars (BSSs) and three turn-off stars (TOs) in the old open cluster (OC) NGC 2682. From the high resolution (R~60,000) spectra obtained by the Subaru / HDS, we derived radial velocity, rotation velocity, and calculated chemical abundances of lithium, carbon and oxygen. Radial velocity of the target stars is consistent with the mean radial velocity of member stars of the cluster. Thus, we confirm the targets are indeed the real members of the cluster. Rotation velocity of BSSs distributes in a wide range of few km/s to hundred km/s, while those of TOs is restricted to a small value (vsini ≦7 km/s) . Both mass transfer scenario and collision scenario are expected to spin up BSSs. Target stars with measured Li abundances show a good agreement to the trend between A(Li) and Teff found in previous works . Moreover, BSSs have C and O abundances not significantly different from those of the TOs. Exceptions are BSS S997 and S1273. S997 shows a slight enhancement in O abundance, while S1273 shows a significant depletion in C abundance and a slight depletion in O abundance compared to other BSSs and TOs in the same cluster. These anomalies in C and O abundances may be interpreted by mass transfer scenario.
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[Speaker 2]
Cheul Hong Min
[Title]
VERA observations of SiO masers in Symbiotic star R Aquarii
[Abstract]
R Aquarii (R Aqr) is one of the closest symbiotic systems and one of the SiO maser sources associated with the Mira variable in Symbiotic star. These systems are very interesting target, and R Aqr is very exciting laboratory because of the existence of jet-like feature.
Though observations of the system have not yielded consistent values of the orbital parameters, the binary parameters of the orbit give an evidence whether or not Roche lobe outflow in the long period variable and interacting stellar winds of the formation of accretion disk and jet in secondary star. VERA has performed the observations toward R
Aqr since 2004. VERA its unique observation system is a powerful tool for astrometry, and we can hopefully obtain information about its orbital motions. In this presentation, I will present the result of VERA observations for R Aqr.

[Speaker 1]
Ayumu Matsuzawa
M2, SOKENDAI, Mitaka（supervisor : Satoru Iguchi）
[Title]
Evaluation of pointing error on ALMA ACA antenna
[Abstract]
The pointing error is difference between actual direction and directed direction of the antenna. I evaluate the activity of scientific performance by pointing error for ALMA antenna. The pointing error of ALMA antenna has three components: The components of antenna, the component of the optical pointing telescope and the components of the atmosphere. The purpose of my research is extract and evaluates the only component of radio antenna. Because, the component of antenna specification be established.
Therefore, the component of antenna can correctly evaluate rather than other two components.
For evaluate the pointing error, I estimate the pointing error from measurement data. The measurement of pointing error uses the optical pointing telescope (OPT). OPT installed in surface of antenna, and shooting a star by CCD in OPT. In the image of CCD, the pointing error assumed the difference center of image between centroid of star. But, this image included same noise. I made a program for remove the noise in image. I confirm that this program perform in ideal image as expected.
The component of antenna has some components (wind, thermal, servo, meterology). For extract these components, I measure the pointing error by Long tracking (measure the pointing error when tracking the one source over 15min). It can extract using the data of resolver and thermocouple. Now, I measure the pointing error by many long tracking, also I will measure the pointing error by Fast switching (measure the pointing error when the antenna is moving fast). After this, I will evaluate the component of radio antenna from pointing error. By this research, I expect improve the precision of pointing error for ALMA antenna.
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[Speaker 2]
Nagisa Shino
D1, SOKENDAI, Mitaka（supervisor : Mareki Honma）
[Title]
Testing the formation scenario of massive star by CH3OH maser
[Abstract]
Now classⅠ CH3OH maser is thought to be associated with outflow, while classⅡ CH3OH maser is thought to be associated with accretion disc.
If this is true, classⅠ CH3OH maser is expected to be distributed perpendicularly with respect to rotating disk.
Detecting (or rejecting) this will play a major role in understanding the scenario of massive star formation.
To do this, we plan to observe distributions of two classes of CH3OH masers with VLBI. For that purpose, first we have to look fortarget sources in which both of classes are detected.
We performed the single-dish observations of both classes of CH3OH maser using Nobeyama 45m and Yamagucchi 32m telescopes.
As a result, we discovered 89 sources detected in both classes.

[Speaker 1]
Katsuya Hashizume
[Title]
The outflow from accretion disk around the Black Hole
[Abstract]
The accretion disks around Black Holes(BHs) are believed to drive high energy astrophysical phenomena , such as high-energy radiation, disk outflows, and jets of Active Galactic Nuclei and black hole binaries.
But, structure of the disks and mechanisms of driving outflow have poorly understood. Especially, super-Eddington accretion disks, of which luminosity exceeds the Eddington luminosity, is a hot debated issue.
If the super-Eddington disks are feasible, the ultra luminous X-ray sources are explained without assuming intermediate mass black holes.
By two-dimensional radiation-hydrodynamics (2D-RHD) simulations, super-Eddington accretion disks around BHs are successfully reproduced, implying that quasi-steady super-Eddington accretion is possible (Ohsuga et al. 2005).However, the computational domain of the simulations is restricted tobe 500 Rs (Schwarzschild radius).Thus, the behavior of outflows at the distant region (>500Rs) is not investigated.
The structure of the super-Eddington flows might change if the outflowing matter of >500Rs get back to the vicinity of the black hole.
In order to understand more realistic structure and dynamics of the super-Eddington flows, it is needed to reperform 2D-RHD simulations with much larger computational domain.
In this talk, I present the fundamental mechanisms of BH accretion disks and outflows,and also my research plan of master thesis.
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[Speaker 2]
Daehyeon Oh
[Title]
Finding Brown Dwarfs in star formation region with subaru telescope
[Abstract]
TBD

２０１２年５月２６日に（土）に国立天文台（三鷹キャンパス）で、特別公開講演および総研大入試ガイダンスが行われました。今年は、３０名以上の方々にご参加いただき、大変な盛り上がりを見せました。また、学生のみならず一般の方も参加され、日本の天文学を国立天文台から社会に発信する良い機会になりました。
特別公開講演では、「新領域を切り開く天文学」をテーマとして、ハワイ観測所の宮崎聡准教授、理論研究部の田中雅臣助教、天文データセンターの大石雅寿准教授による公演が行われました。装置開発からシミュレーションに至るまで最先端の研究を身近に感じられ、参加者にとって大変有意義な時間となりました。また、参加者による質疑応答では、今後日本の天文学がどのように発展して、どんな可能性を秘めているのか、白熱した議論が繰り広げられました。
教員との相談会では、興味・関心のある分野の教員に直接話を聞くことができ、大学院の概要，入試や入学後の学生生活，実際の研究活動などの質疑応答が活発に行われました。また、院生とも交流する場が設けられ、実際の研究生活や、授業、実習などについて詳しく聞けるとても有意義な場となりました。このように、多くの方々にご参加いただけたことで、積極的な質疑応答が交わされ、参加者にも講演者にも大変意義のあるガイダンスとなりました。
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