Nanjing Normal University (China) Associate Professor Shanshan Weng’s Team Published Their Latest Research Results In Nature Astronomy

Recently, a research team led by Associate Professor Shanshan Weng from the School of Physics and Technology  at NNU discovered a special pulsar within the gamma-ray binary LS I +61 303 using FAST (Five-hundred-meter Aperture Spherical radio Telescope) . Their findings were published online in Nature Astronomy with the title “Radio Pulsations from a Neutron Star within the Gamma-ray Binary LS I +61 303”. (

Hundreds of X-ray binaries have been found in the Milky Way and in the Large and Small Magellanic Clouds  , but only eight of them produce high-energy gamma-ray radiation. What physics makes gamma-ray binaries so special is a hot topic in the field of Physics. So far, there have been two prevailing viewpoints. Some scholars believe that gamma rays are generated by shock waves caused by collisions between young pulsars and stellar winds. Others suggest that black holes in the X-ray binaries accrete and produce jets (known as microquasars ) which in turn interact with optical companion material to produce gamma rays. LS I +61 303 is more special among these gamma-ray binaries, as it has shown some unique observational phenomena, such as superorbital variability and short magnetar-like bursts, so it is of great significance for research.

Since the discovery of LS I +61 303 in 1978, there has been a controversy of whether a black hole or a neutron star exists in this binary system. Over the past few decades, numerous observations have been made at various wavelengths in an attempt to search for its pulse signal , but without success. Supported by the FAST team, researchers from NNU and other institutions made four observations of the system using FAST. In one of the observations, a 0.269-second pulse signal was detected for the first time. The result is expected to end the decades-long debate over whether the binary system has a black hole or a neutron star. Due to the importance of the research, two weeks after the paper was submitted for review, it was highly rated by three reviewers, one of whom, named Scott Ransom, believes that the pulse signal detected by FAST is a leap forward in our understanding of LS I +61 303 and that the observation result is crucial and direct as it indicates the presence of a young high-filed pulsar  in the system, contributing to our understanding of the formation and behavior of the system.

The paper has been published online in Nature Astronomy, with NNU as the first unit, Shanshan Weng as the first and corresponding author, Lei Qian, associate researcher of the FAST team and Bojun Wang of Peking University as the co-first authors, and Professor Diego F. Torres of the Institute of Space Sciences  in Spain as the co-corresponding author. Co-authors also include Professor Qirong Yuan of NNU and other researchers from the Purple Mountain Observatory , the Institute of High Energy Physics  of the Chinese Academy of Sciences, and the University of Science and Technology of China , etc. The research is supported by the National Natural Science Foundation of China , Blue Project  of Jiangsu Province, Peng Huanwu Science & Education Cooperation Center  of NNU, and other scientific research institutions.

In 2021, Associate Professor Shanshan Weng and his team detected the panorama of the black hole X-ray binary bursts for the first time using an HXMT (Hard X-ray Modulation Telescope) . The paper was highly praised by reviewers and editors. This achievement, together with several works like the SJ-10  satellite was released at the National Space Science Center of the Chinese Academy of Sciences  and reported by a dozens in the of media, including CCTV. A series of research work shows that the School of Physics and Technology  at NNU has been deeply involved in cutting-edge research with domestic large domestic telescopes, achieving key breakthroughs and effectively enhancing its influence in this field.