FAST discovers three new pulsars in an old globular cluster

Astronomers used the FAST telescope to discover three new pulsars in the ancient globular cluster Messier 15. Two of them were found to be long-period pulsars, and the third was classified as a millisecond pulsar. This discovery was reported in his December 11th article on the preprint server arXiv. Pulsars are highly magnetized rotating neutron stars that emit beams of electromagnetic radiation. Pulsars with a rotation period of less than 30 milliseconds are called millisecond pulsars (MSP). Astronomers believe that binary systems are formed when the more massive component becomes a neutron star, and the neutron star rotates as material accumulates from the secondary star.

Messier 15 (also known as NGC 7078) is approximately 35,700 light-years from Earth. Its estimated mass is 560,000 solar masses. It is one of the oldest clusters (approximately 12 billion years old) and the least metal-poor (metallicity approximately -2.25). Previous observations of Messier 15 have identified nine pulsars, the first of which was identified in 1989. A team of astronomers led by Yuxiao Wu from Chongqing University in China decided to use FAST to search for pulsars in this cluster. The discovered pulsars were named PSR J2129+1210J, PSR J2129+1210K, and PSR J2129+1210L. Observations indicate that PSR J2129+1210J is an MSP and the other two are long-period pulsars.

According to the study, PSR J2129+1210J is a pulsar with a rotation period of about 11.84 milliseconds, and its dispersion was calculated to be 66.68 pc/cm3. The rotation period of PSR J2129+1210K is approximately 1.93 seconds and the dispersion index is 68.01 pc/cm3. The rotation period of PSR J2129+1210L is estimated to be 3.96 seconds. The dispersion index of this pulsar was approximately 67.1 pc/cm3. The researchers noted that while the exact locations of PSR J2129+1210K and PSR J2129+1210L remain unknown, they are likely not far from Messier 15’s core. Further observations are required to determine the exact location.