Single Pulse Studies Of PSR B0950+08 With FAST

Pulsars are a type of hight and ultra-high density compact celestial body with an extremely stable rotation period.They emit periodic signals in the form of single pulses.The study of pulsar emission characteristics is of utmost importance,as it helps us understand interesting physical phenomena and can effectively address some of the challenges in pulsar emission mechanisms.To solve such challenges,various emission mechanism models have been proposed to explain some physical phenomena that occur in the pulsar emission area,but there is currently no universally accepted theoretical model.Studying pulsar emission mechanisms requires multi-band observations to understand unique physical characteristics and has important research implications for constraining pulsar emission geometry models.Among them,the radio band is an important window for studying pulsars on the Earth’s surface,and radio telescopes are one of the key devices for studying pulsars.This article mainly introduces the author’s research on pulsar single pulse observation based on the Five-hundred-meter Aperture Spherical radio Telescope（FAST）.Observing the emission characteristics of pulsars is an important direction in pulsar research.As an important branch of astronomy,single-pulse observations of pulsars are of great significance for understanding the physical equations,emission characteristics,and theoretical models of pulsars.To study more details of single pulses,high-sensitivity telescopes are required for observation.In order to identify the true pulsar signal,it is crucial to eliminate radio interference,and this approach is essential for the study of single pulses.We conducted a detailed study of polarization and single pulses of PSR B0950+08 at 1250 MHz using the Five-hundred-meter Aperture Spherical radio Telescope（FAST）.The sub-pulse energy of PSR B0950+08 is modulated by the₃period,with sub-pulse in the main pulse exhibiting drifting.This pulsar exhibits two different emission states:bright and burst states.Due to their different polarization characteristics,this means that their emission mechanisms and geometries are different.The average profile of this pulsar is mainly composed of main pulse and inter-pulse.We have discovered significant bridge emission between the main and inter-pulse of PSR B0950+08,with the strength of the bridge emission decreasing as frequency increases.For the first time,we found that the bridge emission’s strength decreases as the pulse peak flux density increases.The main and inter-pulse usually come from opposite magnetic poles,but this physical phenomenon is supported even when there is no bridge emission.Earlier studies debated whether the main and inter-pulse came from the same or opposite magnetic poles.However,in this observation data,we found clear bridge emission between the main and inter-pulse,supporting the explanation that they come from the same magnetic pole.Additionally,the energy of a single pulse typically follows a normal or log-normal distribution and does not exceed ten times the average pulse energy.However,giant pulses’energy and peak flux densities differ from normal pulses,with their energy following a power-law distribution and their peak flux density exceeding30 times the mean value.Based on the relative energy and peak flux density distributions,we conclude that PSR B0950+08 does not produce giant pulses.The emission mechanism of pulsars remains a mystery that is difficult to solve.Studying the emission characteristics of main pulse and inter-pulse helps us understand the emission geometry structure of pulsars and can explain whether their emission comes from a single magnetic pole or opposite poles.Bridge emission and giant pulses have always been one of the hot topics in pulsar radio observation and theoretical research.Bridge emission is relatively rare in pulsars,and its emission mechanism and geometric structure are still not very clear,so further theoretical research is needed.The specific physical mechanism for pulsars generating giant pulses also requires further study.In this study,using the world’s most sensitive telescope（FAST）,we conducted detailed observations of the single pulse of PSR B0950+08.Our observations provide a unique opportunity to study the origin of the emission characteristics of this pulsar and the structure of the neutron star’s magnetic field,and provide new insights into the origin of pulsar emission characteristics.