Self-consistent interpretations of the multi-wavelength gamma-ray spectrum of LHAASO J0621$+$3755

Abstract

LHAASO J0621$+$3755 is a TeV gamma-ray halo newly identified by LHAASO-KM2A. It is likely to be generated by electrons trapped in a slow-diffusion zone around PSR J0622$+$3749 through inverse Compton scattering. When the gamma-ray spectrum of LHAASO-KM2A is fitted, the GeV fluxes derived by the commonly used one-zone normal diffusion model for electron propagation are significantly higher than the upper limits (ULs) of Fermi-LAT. In this work, we respectively adopt the one-zone superdiffusion and two-zone normal diffusion models to solve this conflict. For the superdiffusion scenario, we find that a model with superdiffusion index $\alpha \lesssim 1.2$ can meet the constraints of Fermi-LAT observation. For the two-zone diffusion scenario, the size of the slow-diffusion zone is required to be smaller than $\sim 50$ pc, which is consistent with theoretical expectations. Future precise measurements of the Geminga halo may further distinguish between these two scenarios for the electron propagation in pulsar halos.

13 pages (one column), 4 figures, 1 table

References in corpus (12)

• The ATNF Pulsar Catalogue
• Extended gamma-ray sources around pulsars constrain the origin of the positron flux at Earth
• Analytical solutions for energy spectra of electrons accelerated by nonrelativistic shock-waves in shell type supernova remnants
• 3HWC: The Third HAWC Catalog of Very-High-Energy Gamma-ray Sources
• The distribution of the ISM in the Milky Way A three-dimensional large-scale model
• Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622 + 3749 Observed by LHAASO-KM2A
• Absorption of Very High Energy Gamma Rays in the Milky Way
• Fermi Large Area Telescope Fourth Source Catalog Data Release 2
• Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths
• Klein-Nishina effect and the cosmic ray electron spectrum
• Test of the superdiffusion model in the interstellar medium around the Geminga pulsar
• Spectrum and fraction of cosmic ray positrons: results of the anomalous diffusion approach

Cited by in corpus (10)

• Self-Generated Cosmic-Ray Turbulence Can Explain the Morphology of TeV Halos
• Anisotropic diffusion cannot explain TeV halo observations
• Slow diffusion is necessary to explain the gamma-ray pulsar halos
• Gamma-ray halos around pulsars: impact on pulsar wind physics and galactic cosmic ray transport
• Interpretation of the puzzling gamma-ray spectrum of the Geminga halo
• Features of the gamma-ray pulsar halo HESS J1831$-$098
• Constraining the slow-diffusion zone size and electron injection spectral index for the Geminga pulsar halo
• A New Perspective on the Diffuse Gamma-Ray Emission Excess
• PHECT: A lightweight computation tool for pulsar halo emission
• Possible spectral irregularities in the AMS-02 positron spectrum