Experimental Constraints on {\gamma}-ray Pulsar Gap Models and the Pulsar GeV to Pulsar Wind Nebula TeV Connection

TL;DR

This study develops a new multi-wavelength method to analyze gamma-ray pulsar emission models by examining the correlation between pulsar beaming factors and spin-down luminosity, favoring the Outer Gap model.

Contribution

It introduces an innovative technique using PWN TeV flux to constrain pulsar emission models and explores the correlation between GeV and TeV emissions in pulsars.

Findings

Outer Gap model is favored over other models based on the correlation analysis.

A tight correlation between GeV pulsar emission and PWN TeV emission was observed.

The results suggest a potential linear relationship between pulsar GeV and PWN TeV emissions.

Abstract

The pulsar emission mechanism in the gamma-ray energy band is poorly understood. Currently, there are several models under discussion in the pulsar community. These models can be constrained by studying the collective properties of a sample of pulsars, which became possible with the large sample of gamma-ray pulsars discovered by the Fermi Large Area Telescope (Fermi-LAT). In this paper we develop a new experimental multi-wavelength technique to determine the beaming factor $\left( f_\Omega \right)$ dependance on spin-down luminosity of a set of GeV pulsars. This technique requires three input parameters: pulsar spin-down luminosity, pulsar phase-averaged GeV flux and TeV or X-ray flux from the associated Pulsar Wind Nebula (PWN). The analysis presented in this paper uses the PWN TeV flux measurements to study the correlation between $f_\Omega$ and $\dot{E}$. The measured correlation has some features that favor the Outer Gap model over the Polar Cap, Slot Gap and One Pole Caustic models for pulsar emission in the energy range of 0.1 to 100 GeV, but one must keep in mind that these simulated models failed to explain many of the most important pulsar population characteristics. A tight correlation between the pulsar GeV emission and PWN TeV emission was also observed, which suggests the possibility of a linear relationship between the two emission mechanisms. In this paper we also discuss a possible mechanism to explain this correlation.