Pevatron at the Galactic Center: Multi-Wavelength Signatures from Millisecond Pulsars

TL;DR

This paper suggests that unresolved millisecond pulsars near the Galactic Center could be responsible for the observed diffuse gamma-ray and TeV emissions, modeling their cosmic-ray acceleration and interactions.

Contribution

It introduces an analytical model linking millisecond pulsars to high-energy gamma-ray emissions, explaining both GeV and TeV observations in the Galactic Center.

Findings

Reproduces H.E.S.S. TeV observations with pulsar population model.

Suggests 10^4-10^5 millisecond pulsars can account for the emissions.

Highlights potential to constrain pulsar properties with future data.

Abstract

Diffuse TeV emission has been observed by H.E.S.S. in the Galactic Center region, in addition to the GeV gamma rays observed by Fermi. We propose that a population of unresolved millisecond pulsars located around the Galactic Center, suggested as possible candidates for the diffuse Galactic Center excess observed by Fermi, accelerate cosmic rays up to very high energies, and are thus also responsible for the TeV excess. We model analytically the diffusion of these accelerated protons and their interaction with the molecular clouds, producing gamma rays. The spatial and spectral dependences of the gamma rays produced can reproduce the H.E.S.S. observations, for a population of $\sim 10^4-10^5$ millisecond pulsars above the cosmic-ray luminosity $10^{34}\,{\rm erg\,s}^{-1}$, with moderate acceleration efficiency. More precise measurements at the highest energies would allow us to constrain the properties of the pulsar population, such as the magnetic field or initial spin distributions.