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We are studying special periods of transition phases between the "main sequence" stage of stars and the stage when the material that forms the 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 the former 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.
We are conducting observational astrophysical researches through the following major action items in our team. (1) Developing "automation scripts", in which a set of the existing data reduction tools (for synthesizing the data finally used for scientific analyses) can be handled in a series of the automated procedures; (2) Developing new tools of astrophysical data analysis, which can handle the scientific data; (3) Developing several programs which can control radio telescopes and hardwares that shall handle radio observation signals. They are performed on the basis of new knowledge of computer programing such as script languages and deep learning algorithms.
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 recording system as well as a telescope (or telescopes) whose coordinates on Earth have been precisely monitored on Earth.