Hope College Physics Department
Research Experiences for Undergraduates
Summer 2013
Project Summary


Project Title:

Population Studies of Normal Pulsars

Student Name: Andrew Johnson
Student's Home Institution: Hope College
Research Advisor: Dr. Peter Gonthier
Source of Support:

This work is made possible by the generous support of the National Science Foundation (Grant No. RUI: AST-1009731), the NASA Astrophysics Theory and Fundamental Program (NNX09AQ71G and 12-ATP12-0169) and the Michigan Space Grant Consortium as well as internal funds from the Hope College Physics Department.

We present the preliminary results of the latest population synthesis of normal pulsars from the Galactic disk. The Fermi Second Pulsar Catalogue provided many gamma-ray pulsars that can be used to improve and constrain current emission models. We use a modified Markov Chain Monte Carlo method to create cumulative distributions of radio and gamma-ray pulsar characteristics to compare to measured distributions. Empirical radio and gamma-ray luminosity models are included that are period and period derivative dependent with freely varying exponents. During the simulation, the period and period derivative exponents as well as the magnitudes of model luminosities are varied to reproduce the number and birth rates of normal pulsars in the Galaxy. The simulation is normalized to the number of radio pulsars detected in ten radio surveys. Recent studies suggesting the necessity of magnetic field decay have motivated the implementation of a magnetic field decay model, similar in character to the one used magnetic in our previous studies. A simple field decay model is implemented in the code to better account for the observed distribution in the period derivative - period diagram. Such additions are expected to better describe the young, high spin down energy Fermi pulsars.

Publications and Presentations: