(Photo courtesy of the National Astronomical Observatory of the Chinese Academy of Sciences)
"Chinese Sky Eye" found key evidence for the existence of nanohertz gravitational waves
The search for nanohertz gravitational waves is one of the most focused issues in the international field of physics and astronomy. The mainland research team recently used the "Chinese Sky Eye" FAST to detect the key evidence of the existence of nanohertz gravitational waves, which is an important breakthrough in the search for nanohertz gravitational waves.
The study was completed by the Chinese pulsar timing array (CPTA) research team composed of researchers from the National Astronomical Observatory of the Chinese Academy of Sciences and other units, and the relevant results were published online in the academic journal "Astronomy and Astrophysics Research" on June 29.
Gravitational waves are ripples in space-time created by accelerating mass objects in the universe perturbing the surrounding space-time. The gravitational wave signal is extremely weak, but it is a direct means of detecting non-luminous matter in the universe. Due to the lower frequency of gravitational waves produced by more massive objects, the detection of gravitational waves with frequencies as low as nanohertz (minus 9 hertz at 10) is of great significance for understanding supermassive black holes, galaxy merger history, and the formation of large-scale structures in the universe.
Top view of "Chinese Sky Eye" (taken during maintenance). Photo by Xinhua News Agency reporter Ou Dongqu
Li Kejia, the corresponding author of the article and a researcher at the National Astronomical Observatory/Peking University of the Chinese Academy of Sciences, introduced that nanohertz gravitational waves have a very low frequency, a period of several years, and a wavelength of several light-years, which makes the detection work very challenging. The use of large radio telescopes to conduct long-term time observations of a group of millisecond pulsars with extremely regular rotation is the only known means of detecting nanohertz gravitational waves.
In this study, the CPTA research team used the "Chinese Sky Eye" to conduct long-term systematic monitoring of 57 millisecond pulsars, based on independently developed software, analyzed and studied the data spanning 3 years and 5 months, and found evidence of quadrupole correlation signals with nanohertz gravitational wave characteristics at a 4.6 sigma confidence level (false alarm rate less than 1 in 500,000).
Panorama of the "Eye of the Sky of China" (taken during maintenance). Photo by Xinhua News Agency reporter Ou Dongqu
"Nanohertz gravitational wave detection sensitivity is strongly dependent on the observation time span. The research team of the United States, Europe and Australia has carried out the search for nanohertz gravitational waves for about 20 years, and the CPTA research team makes full use of the excellent performance of the 'Chinese Sky Eye', with the advantages of data accuracy, pulsar number and data processing algorithm, so that the mainland nanohertz gravitational wave detection and research has reached the world's leading level. Academician Chang Jin, director of the National Astronomical Observatory of the Chinese Academy of Sciences, said.
According to reports, the National Astronomical Observatory of the Chinese Academy of Sciences will further accelerate the scientific research of nanohertz gravitational wave detection, accumulate longer-term observation data, and help open a new window for the use of nanohertz gravitational waves to detect the universe.
Source: Xinhuanet