The Japanese Radio Astronomy VLBI Network

by H. Takaba
(Radio Astronomy Group)

KNIFE (Kashima Nobeyama Interferometer)

The VLBI experiments between the Kashima 34 m telescope and the Nobeyama 45 m telescope was named KNIFE and had been started at 1989. The baseline length of about 200 km provides the fringe rates of 7 milli-arcsec. at 43 GHz and 13 milli-arcsec. at 22 GHz bands. In the latest session of 5-9 June 1992, mappings of 43 GHz SiO (J=1-0: v=1,2) masers' sources in late type stars and 22 GHz H20 maser sources in late type stars, star forming regions, and an extra-galactic nucleus were done.

UKAI (Usuda Kashima Interferometer)

"UKAI" means the cormorant fishing in Japanese; connects ropes to the neck of cormorants and the cormorant fisherman on a boat operates the birds to catch the Japanese trout "AYU" (astronomers think the most delicious river fish in the world). The Usuda 64 m antenna and the Kashima 34 m telescope interferometer is able to catch very little fishes (very faint objects) because of their large mouths (large apertures). The baseline length is about 200 km as well, working frequency bands are 1.6 GHz, 2 GHz, 8 GHz, and 22 GHz.

A monthly VLBI monitoring program of a gravitational lens candidate PKS1830-211 at the S band has been running since November 1991.

Recent results of these experiments will be presented at the IAU Colloquium No. 140 in October 1992.

New Stations

The National Astronomical Observatory is constructing a new 10 m antenna at the Mizusawa Observatory and the old 6 m millimeter wave telescope (now in Nobeyama Observatory) will be moved to Kagoshima, a southern part of Japan. These two antennas will be functional as the VLBI stations in the early 1993.

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