2007 Fiscal Year Final Research Report Summary
Study of Galactic Center Region by Japanese VLBI Network
| Project/Area Number |
17340055
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Kagoshima University |
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Principal Investigator |
OMODAKA Tbshihiro Kagoshima University, Executive Director (50129285)
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| Co-Investigator(Kenkyū-buntansha) |
HABE Tomoo Hokkaido University, Faculty of Science, Associate Professor (90180926)
FUJISAWA Kenta Yamaguchi University, Faculty of Science, Associate Professor (70311181)
KOBAYASHI Hideyuki National Astronomical Observatory(NAO) Mizusawa VERA Observatory, 国立天文台, Professor (20211906)
KAWAGUCHI Noriyuki National Astronomical Observatory(NAO) Mizusawa VERA Observatory, 国立天文台, Professor (90214618)
IMAI Hiroshi Kagoshima University, Facultyof Science, Associate Professor (70374155)
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| Project Period (FY) |
2005 – 2007
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| Keywords | VLBI / Galactic Center / maser / phase-referncing VLBI / compensation of atmospheric phase fluctuations / dark matter |
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| Research Abstract |
7. By using VERA, we started the first step towards determination of the rotation curve of the Galaxy outside the solar cycle (Honma et al. 2007). We also deconvolved the rotation curve of the Galaxy into a bulge and obtain masses and scale radii of the bulge and disk (Sofue et al. 2008).
Recently, an accurate measurement of rotation velocity of 200kms-1 was obtained at a galactocentric radius of 13. 1 kpc using VERA from parallax-proper motion measurement and radial velocities by VLBI phase-referencing observations. This observation has given a strong constraint on the flat rotation in the outer disk of the Galaxy (Honma et al. 2007).Many papers using JVN and VERA were published. Main results of this project are the followings.
1.We We succeeded the VLBI observations by using e-VLBI system with a joint development between NAO, Gifu University and NICT. So we open up the outlook for high sensitivity VLBI observations. By using the e-VLBI system, we started monitoring observations of Sgr
… More
A*.
2. We developed a new Software-Based Broadband Digital Spectrometer and installed them on Kagoshima 6m telescope, Kashima 34m telescope and VERA-Iriki 20m telescope.By using them, we speed up survey observations of both water and Sio masers toward Galactic Center molecular clouds.
3. In the central molecular zone (CMZ), it is one of the biggest question that the molecular gas temperature is much warmer than the dust temperature. We made simultaneous observations in the NH3 (J,K)= (1,1), (2,2), (3,3) lines using 6m telescope at Kagoshima. We suggested that NH3 molecules in the CMZ were produced on the dust grains with the formation temperature of 9-16K, and were released into the gas phase by the. passage of shock wave.
4.Using VERA, we have made monitoring VLBI observations of SiO masers associated with late-type stars (NML Tau etc.).
5.Near infrared monitoring observations of AGB stars exciting bright SiO masers have been made with the Kagoshima University lm telescope. Distances are estimated using a period-luminosity relation of Mira variables determined by Feast et al, (1989).
7. By using VERA, we started the first step towards determination of the rotation curve of the Galaxy outside the solar cycle (Honma et al. 2007). We also deconvolved the rotation curve of the Galaxy into a bulge and obtain masses and scale radii of the bulge and disk (Sofue et al. 2008). Less
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