Analysis of Pulsar Nulling Fractions from the AO327 Survey

Presenters/Authors(s)

Rachel King, Maura McLaughlin, Paul Brook

Abstract or Description

Pulsars are rapidly rotating neutron stars, a type of stellar remnant left behind after the collapse of massive stars. We typically receive highly regular repeating radio signals from pulsars. However, some pulsars experience a phenomenon called nulling where this emission becomes undetectable for anywhere from seconds to hours. It is not yet understood why pulsars null. This project aims to analyze pulsar observations from the AO327 drift scan survey. From known pulsar observations in the survey, 235 data files containing single pulse data were created.  Nulling fractions were calculated using a python Jupyter Notebook by comparing the intensity of individual pulses to the noise in between the pulses. The nulling fractions were calculated using two different methods. One method, used by Wang et al. in 2007 arrives at a nulling fraction by comparing flux density histograms. The second Bayesian method maximizes the likelihood of various pulsar parameters to obtain the most likely nulling fraction. The calculated nulling fractions will be used to identify trends in nulling characteristics, such as the length of nulls and the types of pulsars that null. This information will help scientists better understand pulsar nulling. Because the pulse emission mechanism itself is not very well understood, understanding the reasons behind pulsar nulling will help us better constrain the physics behind pulsar emission.