Ye Xu

Associated Researcher(Associated Professor) in the VLBI and its application in astrophysics group at SHAO

Personal Data
Name:              Ye Xu(familly name:Xu)
Date of Birth:   March 29,1962
Place of Birth:  Jiang Su,China
Telephone:      +86-21-64386191-528
Fax Number:  +86-21-64384618
E-mail:            yxu@shao.ac.cn

Education

1999-2002 Shanghai Astronomical Observatory,Shanghai,China,PhD,in Astrophysics

1996-1999 Shanghai Astronomical Observatory,Shanghai,China,M.S.in Astrophysics

Related Honors

2002-03 Chinese Post Doctoral Found

2001 Chinese Academy of sciences PEN YIN-GANG Science and Technology Scholarship

Scientific experience

I entered Shanghai Astronomical Observatory (SHAO) in 1996 as a M.S. candidate. My main research field was Radio Astronomy, especially astronomical masers. I have also done some work in other fields during M.S.,for example, a work about the outflow velocity in axis-symmetric envelope of AGB stars.

After getting my M.S., I continued to pursue my Ph.D and work in the same field as before in SHAO. From then on, I am engaging in study on molecular lines associated massive star-formingregions and molecular clouds.

I worked at Nanjing University as a Post Doc from 2002 to 2004. Now I work at ShAO as an associated professor. My interest is not only massive star formation, but the Milky Way structure.

In order to probe the size and kinematics of the Milky Way. We are now ready to start preparing for a large program to measure parallaxes and proper motions to massive star forming regions. As a pilot study we recently carried out the observation of 12 GHz methanol masers to see if they could be used for trigonometric parallax measurements. Our observation was extremely successful. We have measured the parallax and proper motion of W3OH. The parallax = 0.514±0.08 mas (1.946±0.03 kpc). It resolves the long-standing problem of the distance to the Perseus arm, which toward W3OH has a kinematic distance of 4.2 kpc and an O-star luminosity distance of 2.2 kpc. Clearly the O-star distance is correct and thus the Perseus arm is strongly kinematically anomalous. The proper motions in the RA and Dec coordinates were -1.204 ±0.02 and -0.147 ± 0.01 mas y-1, respectively. From our results, we believe that VLBA can map out the spiral structure and full kinematics of the Milky Way. In future, we will carry out a large project to study the spiral structure and kinematics of the Milky Way. We will accomplish this by determining distances, via trigonometric parallax, and proper motions of star forming regions in the Milky Way. The target sources are 12 GHz methanol masers which are associated with young massive stars and compact HII regions that trace spiral structure. With accurate distance measurements we will locate spiral arms, and with absolute proper motions we can determine the 3-dimensional motions of these massive young stars.

Accepted Proposals

Massive outflows associated with methanol sources, (Nobeyama 45m, 2004),
Y. Xu, X. Chen, Z.Q. Shen, A. Miyazaki
The Spiral Structure and Kinematics of the Milky Way (VLBA, 2004, Large Proposal),
M.J. Reid, K. M. Menten, Y. Xu, X.W. Zheng, L. Moscadelli, L. Greenhill
Parallaxes and Proper Motions of Massive Star Forming Regions, Step2 (VLA, 2004)
Y. Xu, M.J. Reid, K. M. Menten, X.W. Zheng, L. Moscadelli
Parallaxes and Proper Motions of Massive Star Forming Regions, Step1 (VLA, 2004)
M.J. Reid, K. M. Menten, Y. Xu, X.W. Zheng, L. Moscadelli
The Distance to the Persius Spiral Arm, (VLBA, 2003),
Y. Xu, X.W. Zheng, M.J. Reid, L. Greenhill, K. Menten, L. Moscadelli
Search for calibrators near W30H, (VLA, 2003),
Y. Xu, X.W. Zheng, M.J. Reid, L. Greenhill, K. Menten, L. Moscadelli
A Systematic Study for Massive Outflows, (Nobeyama 45m, 2003),
Y. Xu, J. Yang, X.W. Zheng, K. Sunada, C.C. Pei

Publications

Xu Y. , Yang J., Zheng X.W. et al., 2004, Discovery of Multiple outflows in IRAS 06056+2131, Chin. Phys. Lett, 21, 2071-2072
Xu Y. , Zheng X.W., Jiang D.R., 2003, Kinematical study in the NGC 7538 IRS 1 region, Chin. J. Astron. Astrophys., 3, 133-141
Xu Y. , Zheng X.W., Jiang D.R., 2003, Statistical properties of 6.7 GHz methanol maser sources, Chin. J. Astron. Astrophys., 3, 49-68
Xu Y. , Jiang D.R., Yang, C.Y. et al., 2002, High-velocity gas associated ultra-compact HII regions. Scince in China, 45, 937-945,
Xu Y. , 2001, A possible origin of 6.7 GHz linear methanol maser sources. Chin. J. Astron. Astrophys., 1, 389-394
Xu Y. , Jiang D.R., Zheng X.W. et al., 2001, H2O megamasers in extragalaxies. Progress in as- tronomy, 19, 387-396
Xu Y. , Zheng X.W., Zhang F.J. et al., 2000, Rapid Time Variations of Water Maser Emission in W3(OH) and NGC6334C. A&A; 364, 232-236

Last updated 26 March 2005.