The Bulletin of The Korean Astronomical Society (천문학회보)

The Korean Astronomical Society (한국천문학회)
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Simultaneous VLBI observations of H2O and SiO masers toward VX Sgr using KVN

  • Yoon, Dong-Hwan (Astronomy program, Department of Physics and Astronomy, Seoul National University) ;
  • Cho, Se-Hyung (Korea Astronomy and Space Science Institute) ;
  • Yun, Youngjoo (Korea Astronomy and Space Science Institute) ;
  • Choi, Yoon Kyung (Korea Astronomy and Space Science Institute) ;
  • Rioja, Maria (International Center for Radio Astronomy Research, M468, The University of Western Australia) ;
  • Dodson, Richard (International Center for Radio Astronomy Research, M468, The University of Western Australia) ;
  • Kim, Jaeheon (Shanghai Astronomical Observatory, Chinese Academy of Sciences) ;
  • Kim, Dongjin (Department of Astronomy, Yonsei University) ;
  • Yang, Hanul (Astronomy program, Department of Physics and Astronomy, Seoul National University) ;
  • Imai, Hiroshi (Department of Physics and Astronomy, Kagoshima University) ;
  • Byun, Do-Young (Korea Astronomy and Space Science Institute)
  • Published : 2017.04.10
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Abstract

We performed simultaneous VLBI observations of H2O 616-523 (22.2 GHz) and SiO v=1, 2, J=1-0 (43.1, 42.8 GHz) and v=1, J=2-1, J=3-2 (86.2, 129.3 GHz) masers toward VX Sagittarius using the Korean VLBI Network (KVN). The astrometrically registered maps of the 22.2 GHz H2O and 43.1, 42.8, 86.2 SiO masers were successfully obtained at two epochs of 2016 February 27 and 2016 March 27 by adopting the Source Frequency Phase Referencing (SFPR) method. In addition we detected 129.3 Ghz SiO maser at second epoch. These results make it possible to determine the accurate position of central star as a dynamical center of 22.2 GHz H2O maser and relative locations of 43.1, 42.8, 86.2, 129.3 GHz SiO masers. In addition, it is possible to investigate the morphological and kinematic variations of clumpy structures from SiO maser to H2O maser regions in future together with the development of asymmetric structure of H2O maser region.

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