MATHEMATICAL SCIENCES

Some pulsars have progressed in follow-up time-dependent research


Pulsars are rapidly rotating neutron stars that are one of the products of supernova explosions at the end of stellar evolution. Pulsars have the density of atomic nuclei and are the universe’s natural laboratory for extreme physics. Its super-strong gravitational field provides unique conditions for testing general relativity. Pulsars can accurately measure their rotation parameters, astrometric parameters, and binary orbital parameters, and can calculate the magnetic field, age and energy loss rate of pulsars through rotation parameters.

Recently, Wu Qingdong, a doctoral student in the pulsar cluster group of the Xinjiang Astronomical Observatory of the Chinese Academy of Sciences, and his collaborators used the “Chinese Sky Eye” (FAST) to study some pulsars discovered by drift-scanning multi-scientific target simultaneous sky survey (CRAFTS) after follow-up time, and obtained the basic properties of 2 millisecond pulsars and 22 normal pulsars. The study contributes to a more comprehensive exploration of the physical properties and population properties of neutron stars. The research was published in the Monthly Proceedings of the Royal Astronomical Society (MNRAS).

Compared to the more than 3300 known pulsars, the 24 pulsars studied in this work are fainter, more distant, older, and have a small rate of rotational energy loss. Among them, the energy loss rate of J0211+4235 and J0518+2431 is smaller than the classical death line, while the pulsar radio radiation below the death line should theoretically disappear, so they can be used to test and limit various death line theories. The single pulse sequence of 10 pulsars is “extinguished” by radiation in some cycles, and there is obvious zeroing phenomenon, and J0540+4542 exhibits subpulse drift, which lays a measured foundation for the theory of limiting radiation. In addition, the measured dispersion of the five pulsars is higher than predicted by the electron density model, which means that the electron density model needs to be improved at high silver latitudes to help accurately depict the electron distribution of the Milky Way. The polarization observation properties of the four pulsars are consistent with the rotational vector model. This study enriches the observation characteristics of pulsars and provides measured samples for related theoretical models.

Left: Timed residual plot of 24 pulsars; Right: 12 pulsars with zero elimination, subpulse drift, or radiation modulation.

Later researchers will conduct dating studies on more new pulsars, in order to detect massive pulsars to limit the equations of state of matter of neutron stars, and discover more stable millisecond pulsars for pulsar timing arrays (PTA) and nanohertz gravitational wave detection. (Source: Xinjiang Astronomical Observatory, Chinese Academy of Sciences)

Related paper information:https://doi.org/10.1093/mnras/stad1323

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