Modeling and Maximum Likelihood Fitting of Gamma-Ray and Radio Light Curves of Millisecond Pulsars Detected with Fermi

TL;DR

This paper models and fits gamma-ray and radio light curves of millisecond pulsars detected by Fermi, using geometric emission models and maximum likelihood techniques to understand their emission regions and geometries.

Contribution

It introduces a comprehensive fitting approach for MSP light curves with geometric models, constraining emission regions and viewing geometries.

Findings

Models reproduce observed light curves well

Constraints on emission region altitudes

Broader range of magnetic inclination angles in MSPs

Abstract

Pulsed gamma rays have been detected with the Fermi Large Area Telescope (LAT) from more than 20 millisecond pulsars (MSPs), some of which were discovered in radio observations of bright, unassociated LAT sources. We have fit the radio and gamma-ray light curves of 19 LAT-detected MSPs in the context of geometric, outer-magnetospheric emission models assuming the retarded vacuum dipole magnetic field using a Markov chain Monte Carlo maximum likelihood technique. We find that, in many cases, the models are able to reproduce the observed light curves well and provide constraints on the viewing geometries that are in agreement with those from radio polarization measurements. Additionally, for some MSPs we constrain the altitudes of both the gamma-ray and radio emission regions. The best-fit magnetic inclination angles are found to cover a broader range than those of non-recycled gamma-ray pulsars.