DATE2023.01.12 #Press Releases

Japan’s first Fast Radio Burst detection

Researchers observed a bright radio wave burst from a repeating Fast Radio Burst, a mysterious astronomical phenomenon. 

January 12, 2023

A team of Japanese researchers detected a bright radio pulse from an active repeating Fast Radio Burst (FRB20201124A) using a 64m radio telescope at the Usuda Deep Space Center/JAXA. Fast Radio Bursts (FRBs) are like mysterious fireworks in the Universe. They are short-lived (<<1s) radio wave emissions of unknown origins and emission mechanisms. 

Figure 1. The team used a 64 m radio telescope at the Usuda Deep Space Center/JAXA. The red line represents an actual radio wave curve of the FRB that the team detected. The top right image shows the galaxy at 1.5 billion light years where the FRB emerged. Photo credits: JAXA/ GREAT2 project (Usuda 64-m telescope) and the Pan-STARRS1 Surveys (PS1), and the PS1 public science archive (top right image).

“I learned about the existence of FRBs when I was an undergraduate student. The fact that FRBs are newly discovered and unknown objects intrigued me, and I strongly wanted to detect FRBs,” says Sota Ikebe, a master's student from the University of Tokyo and an author of the research paper. “Pulsars (including FRBs) are one of the many mysterious objects in the universe, and because they emit signals so quickly and dynamically from nanosecond to millisecond, I feel as if they are alive,” adds Kazuhiro Takefuji, a research scientist at JAXA and one of the researchers involved in this research. 

FRB20201124A is one of the most active repeating FRBs. It was discovered in 2020, detected in 2021, and then again in 2022. In 2022, the team of researchers noticed one of the brightest events identified from FRB20201124A. So bright that the energy density of the burst is comparable to those of bright populations of one-off FRBs. The frequency of the bright burst was also the highest (~2.2-2.3GHz) ever reported for this FRB. The findings suggest that some repeating FRBs can be as bright as some one-off FRBs. But, on average, repeating FRBs could be fainter than one-off FRBs. So, due to the sensitivity limitations of current radio telescopes, astronomers may misclassify repeating FRBs as one-off bursts. 

The team surmises that some of the one-off events might be a part of repeating bursts. But only the brightest and rare population of repeating FRBs can be detected and misclassified as one-off FRBs. To test the team's predictions, researchers need to monitor both one-off and repeating FRBs and conduct follow-up observations. 

“Uncovering the origin of FRBs is exciting because more than 1000 mysterious fireworks are happening daily in the sky, which no one had noticed before. It is my honor to work on one of the most important missions in modern astronomy,” says Tetsuya Hashimoto, an Assistant Professor at National Chung Hsing University and an author of the research paper. “It was my big surprise that even an old radio telescope could conduct cutting-edge science in astronomy.” 

Publication details

Journal	Publications of the Astronomical Society of Japan (PASJ)
Title	Detection of a bright burst from the repeating FRB 20201124A at 2 GHz
Authors	Sota Ikebe , Kazuhiro Takefuji , Toshio Terasawa, Sujin Eie, Takuya Akahori, Yasuhiro Murata, Tetsuya Hashimoto , Shota Kisaka, Mareki Honma , Shintaro Yoshiura, Syunsaku Suzuki, Tomoaki Oyama, Mamoru Sekido, Kotaro Niinuma, Hiroshi Takeuchi, Yoshinori Yonekura and Teruaki Enoto
DOI	10.1093/pasj/psac101

The Department of Physics at National Chung Hsing University