On the Expected Orbitally-modulated TeV Signatures of Spider Binaries: The Effect of Intrabinary Shock Geometry

TL;DR

This paper models the expected TeV gamma-ray signatures from spider binary systems, considering various shock geometries and emission processes, to aid in future observational constraints on these systems.

Contribution

It introduces an improved emission model with updated synchrotron kernels and shock geometries for predicting TeV signatures in spider binaries.

Findings

Enhanced predictions of phase-dependent TeV spectra.

Constraints on particle acceleration and shock properties.

Potential for guiding future Cherenkov telescope observations.

Abstract

'Spider' binary systems - black widow and redback compact binaries differentiated by their companion's mass and nature - are an important type of pulsar system exhibiting a rich empirical phenomenology, including radio eclipses, optical light curves from a heated companion, as well as non-thermal X-ray and GeV orbital light curves and spectra. Multi-wavelength observations have now resulted in the detection of >~50 of these systems in which a millisecond pulsar heats and ablates its low-mass companion via its intense pulsar wind. Broadband observations have established the presence of relativistic leptons that have been accelerated in the pulsar magnetosphere and near the intrabinary shock, as well as a hot companion, presenting an ideal environment for the creation of orbitally-modulated inverse Compton fluxes that should be within reach of current and future Cherenkov telescopes. We have included an updated synchrotron kernel, different parametric injection spectral shapes, and several intrabinary shock geometries in our emission code to improve our predictions of the expected TeV signatures from spider binaries. Our updated phase-dependent spectral and energy-dependent light curve outputs may aid in constraining particle energetics, wind properties, shock geometry, and system inclination of several spider binaries.