Chinese scientists have discovered two long-period pulsars in the globular cluster M15 using a search strategy based on fast-folding algorithms and systematic analysis of data from China's FAST telescope. This finding unveils a new evolutionary path for pulsars in globular clusters. The research paper was recently published in "Science China: Physics, Mechanics & Astronomy."
According to the description, a globular cluster is a high-density group of stars bound together by gravity, with an evolutionary age typically exceeding ten billion years, making it one of the oldest astronomical systems in the universe. After billions of years of evolution, globular clusters contain a large number of pulsars. By understanding their properties, we can gain insights into the dynamical evolution of globular clusters, stellar population synthesis pathways, and other information. Among the 317 pulsars discovered in 41 globular clusters in the Milky Way, most are millisecond pulsars with rotation periods in the range of tens of milliseconds, with 179 of them existing in binary systems.
Dr. Zhou Dengke from the Astronomy Computation Research Center at Zhejiang Lab, along with Associate Researcher Wang Pei from the National Astronomical Observatory, have discovered two long-period pulsars in the globular cluster M15. These pulsars are named M15K with a rotation period of about 1.9 seconds and M15L with a rotation period of about 3.9 seconds. Notably, M15L currently holds the record for the longest known rotation period among pulsars in globular clusters.
Based on observational data, the research team further speculates that M15K and M15L may have been part of a binary system in their early stages. They likely underwent a brief phase of accretion before interacting with other celestial bodies, disrupting the binary system, and causing the pulsars to evolve into long-period pulsars after losing their companion stars.
The chief scientist of the "China Sky Eye" FAST and corresponding author of the paper, Di Li, stated: "This discovery reveals a new evolutionary path for pulsars in globular clusters. FAST is systematically changing our understanding of pulsars in globular clusters."
Dr. Dengke Zhou, the first author of the paper, mentioned that the field of radio astronomy deals with massive amounts of data, which can be very time-consuming to process. This study utilized intelligent computing technology to significantly enhance the search and identification speed of pulsars, allowing researchers to focus more on understanding the physical images behind the data, thus greatly improving research efficiency.
Academician of the Chinese Academy of Sciences and researcher at Yunnan Astronomical Observatory, Chinese Academy of Sciences, Zhanwen Han, expressed that this achievement is expected to lead to more similar discoveries. Ultimately, we hope to fill the gap in the pulsar population within globular clusters, which is crucial for understanding the formation process and interactions of pulsars in globular clusters.
