I study astronomy, and in particular, the evolution of galaxies. I’m looking for clues about how galaxies were formed and how they have evolved into their forms today, from observations of light and radio waves emitted from active galaxies.
Each active galaxy has a supermassive black hole at its center, which is thought to be the energy source for the emission of light and radio waves. We believe that there is a relationship between the mass of the black hole and that of the galaxy, and we are seeking to understand how galaxies evolve by exploring the relationship between these masses.
In my master's course, I focused on the evolution of the active galaxies called quasars. Quasars are typically very bright objects, but some are fainter. We have found Many faint quasars have been found at great distances from the earth―that is, quasars that were formed shortly after the birth of the universe―and we have explored their characteristics. From a series of studies using data from the Jansky Very Large Array (JVLA) telescope operated by the US National Radio Astronomy Observatory, we were able to deduce that the radio emissions from faint quasars of the early universe are quieter than those from bright quasars of the same age.
The use of telescopes around the world is allocated in response to observation proposals submitted by researchers, stating what they wish to observe and for what purpose. In the past, we have used public data for analysis, but we are also working on observation proposals to further advance our research. Our previous JVLA work included data obtained from my observation proposal, and we now plan to investigate the evolution of galaxies from a more multifaceted perspective by observing the distribution of radio emission and hydrogen gas in a type of active galaxy known as radio galaxies. The analysis of this observation data and the approval of my observation proposal have given me great confidence as a researcher. I am really looking forward to future observations.
When I was a child in my hometown in Taiwan, I became interested in astronomy after watching a video given to me by my parents, making me wonder about the many phenomena in the universe. After graduating with a physics degree from NTU, I worked as an engineer at the Academia Sinica Institute of Astronomy and Astrophysics, which is equivalent to the National Astronomical Observatory of Japan. There, I was involved in the development of a receiver for the ALMA radio telescope in Chile.
I decided to go to graduate school because I had longed to study astronomy as a science while I was working. You need a Ph.D. to survive as a researcher, and Japan is a leader in the field of astronomy in Asia. As both the University of Tokyo and NTU are former Imperial universities, I felt a connection between them, and therefore chose to study abroad at the University of Tokyo. When I took the entrance exam for graduate school, I sought help from Professor Kotaro Kohno, my current supervisor, on applying for a scholarship. I am also grateful to Professor Kohno for helping me develop my research plan.
Before going abroad, I studied Japanese as a third language at NTU and practiced my conversation skills in an online forum. As there are foreign students like me in graduate school, English is used in classes, but I think it is more convenient to be able to speak Japanese when you have deep discussions with Japanese teachers and students, and also when you want to talk about daily life.
My immediate goal is to complete my doctorate. I want to acquire advanced knowledge and skills, and make achievements fitting to a Ph.D.
Interview and text: Masatsugu Kayahara
Photography: Junichi Kaizuka
Originally published in The School of Science Brochure 2020