Home > Archives > 2014-02

2014-02

The first astrometry result of the Perseus arm beyond a Galactic longitude l of ~ 190 deg with VERA etc.

[Speaker 1]
Nobuyuki Sakai D3, SOKENDAI, Mitaka(supervisor : Mareki Honma)
[Title]
The first astrometry result of the Perseus arm beyond a Galactic longitude l of ~ 190 deg with VERA
[Abstract]
Contexts. Currently, VERA and VLBA have been conducting kpc-scales astrometry to make a 3D map of the Milky Way Galaxy.
AIms. We aim to expand previous astrometry coverage of the Perseus arm from a Galactic longitude l of ~ 190 deg to that of ~ 240 deg.
This is crucial to accurately understand large scale structure of the Perseus arm.
Methods. We carried out nine-epochs VERA astrometry observations toward massive star-forming region IRAS 07427-2400 (l = 240.3 deg, b = 0.1 deg, Vlsr = 68.0 km/s) between January 20, 2012 and September 16, 2013.
Results. The measured parallactic distance is 5.18 +0.79/-0.59 kpc, which places the source in the 3rd Galactic quadrant of the Perseus arm.
Discussions. A combination of our astrometry result and previous ones reveal that the pitch angle of the Perseus arm is constant (i = 17.7 +/- 1.8 deg) in 94.60 deg < l < 240.32 deg, although the pitch angle is changed significantly (i = 11.5 +/- 1.3 deg) in 43.17 deg < l < 94.60 deg. The difference indicates that bifurcation or spur as seen in external disk galaxies may occur in 43.17 deg < l < 94.60 deg for the Perseus arm. [Speaker 2] Shino Nagisa D2, SOKENDAI, Mitaka(supervisor : Mareki Honma) [Title] Methanol maser observation of massive star formation region IRAS 18089-1732 [Abstract] The formation scenario of massive star is not yet fully understand. Methanol maser is regarded as the signpost of the formation process of the massive star. Particular, the 44GHz methanol maser is associated with an outflow, and it is said that the 6.7GHz methanol maser is associated with an accretion disk. If this is true, 44GHz methanol 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. In order to test this, we observed 6.7GHz methanol maser using JVN and obtained space distribution map. We also analyzed the VLA archive data of the 44GHz methanol maser. We were able to get the space distribution map of the 44GHz methanol maser and the 6.7GHz methanol maser of IRAS18089-1732. We argue about each emission position from the result.

Development of software for high-precision LLR data analysis etc.

[Speaker 1]
Ryosuke Nagasawa, M1, SOKENDAI, Mitaka(supervisor : Hideo Hanada)
[Title]
Development of software for high-precision LLR data analysis
[Abstract]
We are developing new analysis software for precise determination of lunar orbital/rotational motion and tidal deformation using lunar laser ranging (LLR) observation data.
As the first step of the study, we construct an LLR observation model. This model consists of the lunar orbit and libration obtained from lunar-planetary ephemeris DE430 (provided by NASA JPL), and the other newest physical models compatible with IERS Conventions (2010) such as Earth orientation, solid Earth/Moon tides, and some factors affecting propagation delay. For the purpose of calculating these components precisely, we use the modules of the geodetic data analysis software “c5++” (Otsubo et al., Japan Geoscience Union Meeting 2011). LLR observation data are provided as normal points. In this calculation, there are 3577 points distributed from June 1996 to July 2013, obtained at 4 observatories: Apache Point, Grasse, Matera and McDonald. Comparing the observed and calculated one-way ranges, the mean and the standard deviation of the residuals are about 5.7 cm and 4.8 cm respectively.
The first step has almost finished. Currently we are working on the next step, the integration of lunar motion. This presentation contains the outline of LLR and the current status of the software development, including the details of above-mentioned modeling.

[Speaker 2]
Sumire Tatehora, D1, SOKENDAI, Mitaka(supervisor : Nobuo Arimoto)
[Title]
Morphological studies of high-z massive galaxies
[Abstract]
Thanks to the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDLES) HST/WFC3 imaging with high spatial resolution, we investigate the morphology of galaxies in the distant universe. We select 20 passively evolving galaxies and 586 star-forming galaxies at 1.4<phot-z<2.5 in the COSMOS-CANDELS 210 square arcmin field and measure effective radius and Se ́rsic index by using the GALFIT package (Peng et al. 2002). We present the results of size-mass, Se ́rsic index-mass relation and discuss whether it has correlation between galaxy morphology and BzK color.

The widest separation and low mass planetarymass companion(PMC) candidates around DoAr 25 etc.

[Speaker 1]
Oh Daehyeon D2, SOKENDAI, Mitaka(supervisor : Woko Aoki)
[Title]
The widest separation and low mass planetarymass companion(PMC) candidates around DoAr 25
[Abstract]

[Speaker 2]
Yang Yi M2, SOKENDAI, Mitaka(supervisor : Saeko Hayashi)
[Title]
Direct Imaging of DM Tau in NIR Band
[Abstract]
Circumstellar disks are often observed to be surrounding young stars, especially T Tauri stars. The composition and structure of circumstellar disks have essential effect in the formation of planets. Therefore, investigation of such disks is quite beneficial for us to understand the formation process of the planetary system. In this presentation, I will show the near infrared observation of DM Tau from HiCIAO instrument mounted on Subaru Telescope. This T Tauri star is located in Taurus star formation region which is one of the nearest star formation regions from the Solar System. Hence it is easy to resolve the detailed structure of its disk. I believe this research is quite helpful to figure out the scenario of disk evolution and the ongoing planet formation in that disk.

VERA observatons of SiO masers toward Symbiotic star R Aquarii – Determination of orbital parameters etc.

[Speaker 1]
Min Cheul Hong D2, SOKENDAI, Mitaka(supervisor : Mareki Honma)
[Title]
VERA observatons of SiO masers toward Symbiotic star R Aquarii – Determination of orbital parameters
[Abstract]
Symbiotic stars are now generally understood as binary systems comprising a cool late-type star and a hot compact companion.
Interacting between the components presents a good laboratory for studying variety of physical processes, and their study gives important implications for the binary evolution.
R Aquarii (R Aqr) is one of the closest and most studied symbiotic star, but its orbital parameters are still under debated.
In order to extract the orbital parameters, we have been observing the R Aqr system of the SiO maser with the VERA (VLBI Exploration of Radio Astrometry) which can allows us to conduct precise astrometry of the maser sources.
Here, I will report observational results of the preliminary orbital parameters for R Aqr system.

[Speaker 2]
Onitsuka Masahiro M2, SOKENDAI, Mitaka(supervisor : Tomonori Usuda)
[Title]
Infrared Transit Observations of the Very Young Hot Jupiter CVSO30b
[Abstract]

Home > Archives > 2014-02

Search
Feeds

Return to page top