Emission Variation of a Long-period Pulsar Discovered by the Five-hundred-meter Aperture Spherical Radio Telescope (FAST)

TL;DR

This study analyzes the emission variability of pulsar PSR J1900+4221 using FAST, revealing diverse pulse behaviors, profile shape changes, and weak emission states, contributing new insights into pulsar emission mechanisms.

Contribution

It provides the first detailed analysis of emission variations and nulling behavior of PSR J1900+4221 observed with FAST, highlighting complex pulse dynamics.

Findings

Detection of nulling, regular, and bright pulses with distinct distributions

Moderate correlation between leading and trailing components

Estimated inclination angle of about 7 degrees

Abstract

We report on the variation in the single-pulse emission from PSR J1900+4221 (CRAFTS 19C10) observed at frequency centered at 1.25 GHz using the Five-hundred-meter Aperture Spherical radio Telescope. The integrated pulse profile shows two distinct components, referred to here as the leading and trailing components, with the latter component also containing a third weak component. The single-pulse sequence reveals different emissions demonstrating as nulling, regular, and bright pulses, each with a particular abundance and duration distribution. There also exists pulses that follow a log-normal distribution suggesting the possibility of another emission, in which the pulsar is radiating weakly. Changes in the profile shape are seen across different emissions. We examine the emission variations in the leading and trailing components collectively and separately, and find moderate correlation between the two components. The inclination angle is estimated to be about 7{\deg} based on pulse-width, and we discuss that nulling in this pulsar does not seem to show correlation with age and rotation period.