East Asia VLBI Network

About Japanese VLBI Network

Japanese VLBI network is a collabration of 4 institutes and 7 universities in Japan and now there are 12 radio telescopes from north to southern island in Japan. The VERA (VLBI Exploration of Radio Astrometry) VLBI array consist of 4 stations which have special instruments for VLBI astrometry. Because the radio telescopes in JVN have also their own project, the JVN carries out several observations in year after negotiating their opeartion schedules.

The radio telesopes of JVN have various performance, for example, the diameter of main dish is 11 to 64 meters. Half of them have a diameter of over 30 m, especially five of six big main dish telescopes are located within a diameter of ~200 km that is quite rare VLBI network in the world. The VERA telecope has also unique instruments which are specialized for the VLBI astrometry, that is the phase referencing VLBI. Other radio telescopes of JVN have also unique own project.

The science by JVN is various fields. The VERA measured annual parallax towards distant star forming regions and evolved stars in the Milky Way and the VERA will reveal a true structure and dynamics of the Milky Way. On the other hand, the JVN detected rotation/infall motion of protostellar disk around massive star and also very interested outflows from the protostars. The flux variation of jets from AGNs was also detected by JVN/VERA, their longer monitering observation showed us very interesting results.

The KVN and Japanese astronomers also developed a new and powerful correlator which is called KJCC (Korea-Japan Joint VLBI Correlator). The KJCC will be main correlator of the EAVN.

see details in Japanese VLBI Network web site

Brief History

  • 1989 1st astronomical VLBI in Japan, Kashima-Nobeyama INterFerometory (KNIFE) was operated
  • 1993 2nd Japanse VLBI network, J-Net (until 2002)
  • 1998 1st space VLBI satellite, VSOP (until 2006)
  • 2003 VERA (VLBI Exploration of Radio Astrometry) operation start
  • 2005 Japanese VLBI Network (JVN) operation start

KASI logo image

EAVN ( East Asia VLBI Network)