KEYWORDS
#1. Death and birth of stars
We observe the phenomena seen in the stellar evolution stage, after the "main sequence", when copious gas and dust are ejected from the dying stars. We also observe the phenomena seen around the stars that are newly born from condensed interstellar medium. Some of the phenomena can be seen for a moment of a star's life. It is difficult to look for them so that we need research strategy enabling us to find them, skills of data analysis that can exactly catch them, and accurately interpret what may happen in them. Therefore, comprehensive knowledge of physics, chemistry, and mathematics as tools for quantitative analysis and discussion.
#2. Interstellar and circumstellar matters
The Milky Way (Amanogawa Galaxy) contains in its large volume interstellar matter that is the material of newly born stars. Some part of the interstellar medium contains "circumstellar material" that was released from stars in their final evolution and deaths. In order to elucidate in detail such "recycling of matter in the universe", it is crucial for search for the matter in wide sky areas of the Milky Way, but the surveys are time-consuming. In particular, the "hierarchical structures" in the interstellar medium are seen from one astronomical unit (au = 150 million kilometers) to one kilo-parsec (kpc=200 million au) and should be explored for understanding how the gas and dust in the interstellar and circumstellar matters are distributed and collected on specific timescales so as to form newly born stars.
#3. Analyses of astronomical observation data
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 reducing raw data and synthesizing image cubes) can be handled in a series of the automated procedures and the data for scientific analyses are finally yielded; (2) Developing new tools of astrophysical data analysis for new discoveries, which can proceed unique scientific interpretations, and in which script languages such as python and deep/machine learning algorithms are introduced; (3) Developing several programs which can smoothly operate a radio observation system or control a new observation system for testing and commissioning.
#4. Radio interferometry (interferometer)
Nowadays high-quality radio images are synthesized using the technique of interferometry. Higher sensitivity needs a larger signal collecting area of a radio telescope such as either a single-dish telescope with a larger aperture or a larger cluster of small telescopes that are synchronized. Higher angular resolution needs either a larger diameter of a single-dish telescope or longer baselines of a radio interferometer of small telescopes. VLBI (very long baseline interferometry) yields often intercontinental interferometry. The VLBI stations operate telescopes whose terrestrial coordinates are accurately determined and monitored, high accuracy clocks (frequency standard systems), and high-speed recording systems.
#5. International collaborations
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 enables us intensively and effectively communicates 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.