Radio and Gamma-Ray Constraints on the Emission Geometry and Birthplace of PSR J2043+2740

TL;DR

This study analyzes gamma-ray and radio data of the old pulsar PSR J2043+2740 to understand its emission geometry, birth location, and evolution, providing insights into gamma-ray emission mechanisms in aging pulsars.

Contribution

It combines gamma-ray lightcurve analysis with radio polarization data to constrain the pulsar's emission geometry within specific theoretical models, a novel approach for this pulsar.

Findings

Gamma-ray lightcurve shows two sharp peaks 0.353±0.035 periods apart.

Constrained the pulsar's magnetic inclination and viewing angles using geometrical models.

Estimated the pulsar's birth location and proper motion, suggesting high velocity.

Abstract

We report on the first year of Fermi gamma-ray observations of pulsed high-energy emission from the old PSR J2043+2740. The study of the gamma-ray efficiency of such old pulsars gives us an insight into the evolution of pulsars' ability to emit in gammma rays as they age. The gamma-ray lightcurve of this pulsar above 0.1 GeV is clearly defined by two sharp peaks, 0.353+/-0.035 periods apart. We have combined the gamma-ray profile characteristics of PSR J2043+2740 with the geometrical properties of the pulsar's radio emission, derived from radio polarization data, and constrained the pulsar-beam geometry in the framework of a Two Pole Caustic and an Outer Gap model. The ranges of magnetic inclination and viewing angle were determined to be {alpha,zeta}~{52-57,61-68} for the Two Pole Caustic model, and {alpha,zeta}~{62-73,74-81} and {alpha,zeta}~{72-83,60-75} for the Outer Gap model. Based on this geometry, we assess possible birth locations for this pulsar and derive a likely proper motion, sufficiently high to be measurable with VLBI. At a characteristic age of 1.2 Myr, PSR J2043+2740 is the third oldest of all discovered, non-recycled, gamma-ray pulsars: it is twice as old as the next oldest, PSR J0357+32, and younger only than the recently discovered PSR J1836+5925 and PSR J2055+25, both of which are at least 5 and 10 times less energetic, respectively.