PHECT: A lightweight computation tool for pulsar halo emission

TL;DR

PHECT is a lightweight software tool that models pulsar halo gamma-ray emission, incorporating complex transport models beyond standard diffusion, and is user-friendly with YAML configuration.

Contribution

Introduces PHECT, a flexible, stable, and easy-to-use software for modeling pulsar halo emission with advanced transport models.

Findings

PHECT can simulate pulsar halo emission using various transport models.

The tool remains stable on non-uniform grids and with discontinuous diffusion coefficients.

PHECT is ready for high-precision observational data and expanding pulsar halo samples.

Abstract

$\gamma$-ray pulsar halos, most likely formed by inverse Compton scattering of electrons and positrons propagating in the pulsar-surrounding interstellar medium with background photons, serve as an ideal probe for Galactic cosmic-ray propagation on small scales (typically tens of parsecs). While the associated electron and positron propagation is often modeled using homogeneous and isotropic diffusion, termed here as standard diffusion, the actual transport process is expected to be more complex. This work introduces the Pulsar Halo Emission Computation Tool (PHECT), a lightweight software designed for modeling pulsar halo emission. PHECT incorporates multiple transport models extending beyond standard diffusion, accounting for different possible origins of pulsar halos. Users can conduct necessary computations simply by configuring a YAML file without manual code edits. Furthermore, the tool adopts finite-volume discretizations that remain stable on non-uniform grids and in the presence of discontinuous diffusion coefficients. PHECT is ready for the increasingly precise observational data and the rapidly growing sample of pulsar halos.