VLBI Exploration of Radio Astrometry
Four 20 m dish telescopes in Japan, that are specially equipped with the dual-beam receiving system, dedicated for high precision trigonometry of radio sources, and operated since 2002
We are studying "dark sides" of stellar evolution in radio wavelength using a special observational technique so-called "interferometry"
Student interview video (produced in 2022 June)
We are studying special periods of transition phases between the "main sequence" stage of stars and the stage when the material that will form next-generation stars is distributed in the interstellar and circumstellar spaces. Because such phases of death and birth of stars are much shorter than the main sequence stage, it is difficult to study these stages without excellent strategies to look for the target stars and "stellar objects" and comprehensive knowledge of physics, chemistry, and mathematics as tools for quantitative analysis and discussion.
The matters that would be released from evolved and dying stars and will be collected to form the next generation of stars are distributed in huge volumes of the Milky Way (Amanogawa) Galaxy and external galaxies. Large sky surveys are one of our challenging issues for elucidating the whole picture of the "re-cycling" of cosmic matter. In particular, it is crucial to explored its "hierarchical" structures from one astronomical unit (AU=150 million-kilometers) to one kilo-parsec (kpc=200 million-AU) for understanding how the gas and dust in the interstellar and circumstellar matters are distributed and collected on specific timescales.
High quality radio images of studied celestial objects can be nowadays synthesized using the "interferometry technique". Image synthesis in higher sensitivity needs a larger aperture area of a radio telescope or, alternatively, a larger number of small telescopes whose received radio signals are correlated or synchronized with each other. Higher angular resolution of images is yielded with a larger diameter of a telescope or longer "baselines" between small telescopes that shall observe the same target at the exactly same time. Continental and intercontinental interferometry is possible in "very long baseline interferometry" (VLBI) technique, in which the individual "stations" have accurate clocks (frequency standards) and a high-speed signal transmission and recording systems as well as a telescope (or telescopes) whose coordinates on Earth have been precisely monitored on Earth.
The large sky surveys and VLBI observations described above need international or global collaborations. They have been constructed through exchanges in fresh information, research ideas, observation opportunities, and direct visits over years and decades. The present information technologies enable us intensively and effectively communicate with foreign colleagues towards establishments of research teams and organizations. Fluent communications in English language will provide our global views in not only astronomy and astrophysics but also a wider variety of friendship and human activities.
Other projects joining as associate members