Anisotropic diffusion cannot explain TeV halo observations

Abstract

TeV halos are regions of enhanced photon emissivity surrounding pulsars. While multiple sources have been discovered, a self-consistent explanation of their radial profile and spherically-symmetric morphology remains elusive due to the difficulty in confining high-energy electrons and positrons within ~20 pc regions of the interstellar medium. One proposed solution utilizes anisotropic diffusion to confine the electron population within a "tube" that is auspiciously oriented along the line of sight. In this work, we show that while such models may explain a unique source such as Geminga, the phase space of such solutions is very small and they are unable to simultaneously explain the size and approximate radial symmetry of the TeV halo population.

11 pages, 8 figures

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Cited by in corpus (17)

• The Physics of Pulsar Halos: Research Progress and Prospect
• TeV halos and the role of pulsar wind nebulae as sources of cosmic ray positrons
• HAWC Detection of a TeV Halo Candidate Surrounding a Radio-quiet pulsar
• Ultra-High-Energy Gamma-Ray Astronomy
• Gamma-ray halos around pulsars: impact on pulsar wind physics and galactic cosmic ray transport
• Detection prospects of very and ultra high-energy gamma rays from extended sources with ASTRI, CTA, and LHAASO
• Effect of magnetic field correlation length on the gamma-ray pulsar halo morphology under anisotropic diffusion
• Constraining the slow-diffusion zone size and electron injection spectral index for the Geminga pulsar halo
• Constraints on the $e^{\pm }$ Pair Injection of Pulsar Halos: Implications from the Galactic Diffuse Multi-TeV Gamma-ray Emission
• Extended TeV Halos May Commonly Exist around Middle-Aged Pulsars
• Anisotropic Diffusion of $e^{\pm }$ in Pulsar Halos over Multiple Coherence of Magnetic Fields
• The environment of TeV halo progenitors
• PHECT: A lightweight computation tool for pulsar halo emission
• New estimate for the contribution of the Geminga pulsar to the positron excess
• Self-confinement of relativistic pair beams in magnetized interstellar plasmas: the case of pulsar X-ray filaments
• Investigating the emission signatures of pulsar halo candidate HESS J1813-126
• Anisotropic Diffusion in Pulsar Halos: Interpreting the asymmetric morphology of Geminga and Monogem halos measured by HAWC