Theoretical interpretation of Pass 8 Fermi-LAT $e^{+}+e^{-}$ data

Abstract

The flux of positrons and electrons ($e^{+}+e^{-}$) has been measured by the $Fermi$ Large Area Telescope (LAT) in the energy range between 7 GeV and 2 TeV. We discuss a number of interpretations of Pass 8 $Fermi$-LAT $e^{+}+e^{-}$ spectrum, combining electron and positron emission from supernova remnants (SNRs) and pulsar wind nebulae (PWNe), or produced by the collision of cosmic rays with the interstellar medium. We find that the $Fermi$-LAT spectrum is compatible with the sum of electrons from a smooth SNR population, positrons from cataloged PWNe, and a secondary component. If we include in our analysis constraints from AMS-02 positron spectrum, we obtain a slightly worse fit to the $e^{+}+e^{-}$ $Fermi$-LAT spectrum, depending on the propagation model. As an additional scenario, we replace the smooth SNR component within 0.7 kpc with the { individual sources} found in Green's catalog of Galactic SNRs. We find that separate consideration of far and near sources helps to reproduce the $e^{+}+e^{-}$ $Fermi$-LAT spectrum. However, we show that the fit degrades when the radio constraints on the positron emission from Vela SNR (which is the main contributor at high energies) are taken into account. We find that a break in the power-law injection spectrum at about 100 GeV can also reproduce the measured $e^{+}+e^{-}$ spectrum} and, among the cosmic-ray propagation models that we consider, no reasonable break of the power-law dependence of the diffusion coefficient can modify the electron flux enough to reproduce the observed shape.

15 pages, 12 figures. The Astrophysical Journal, Volume 845, Number 2

References in corpus (19)

• Parameterization of Gamma, e^+/- and Neutrino Spectra Produced by p-p Interaction in Astronomical Environment
• Cosmic-ray electron+positron spectrum from 7 GeV to 2 TeV with the Fermi Large Area Telescope
• Galactic secondary positron flux at the Earth
• Cosmic-ray propagation with DRAGON2: I. numerical solver and astrophysical ingredients
• Galactic electrons and positrons at the Earth:new estimate of the primary and secondary fluxes
• Cosmic Ray Electrons, Positrons and the Synchrotron emission of the Galaxy: consistent analysis and implications
• Cosmic-ray protons, nuclei, electrons, and antiparticles under a two-halo scenario of diffusive propagation
• Quantitative study of the AMS-02 electron/positron spectra: implications for the pulsar and dark matter properties
• Observations of the shell-type SNR Cassiopeia A at TeV energies with VERITAS
• A new look at the cosmic ray positron fraction
• Non-linear diffusive acceleration of heavy nuclei in supernova remnant shocks
• Search for Cosmic-Ray Electron and Positron Anisotropies with Seven Years of Fermi Large Area Telescope Data
• Interpretation of the cosmic ray positron and antiproton fluxes
• The Connection Between the Positron Fraction Anomaly and the Spectral Features in Galactic Cosmic-Ray Hadrons
• Dipole anisotropy in cosmic electrons and positrons: inspection on local sources
• Spiral Arms as Cosmic Ray Source Distributions
• Direct constraints on diffusion models from cosmic-ray positron data: Excluding the Minimal model for dark matter searches
• Planck intermediate results. XLII. Large-scale Galactic magnetic fields
• What could we learn from a sharply falling positron fraction?

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