Implications of the Cosmic Ray Electron Spectrum and Anisotropy measured with Fermi-LAT

Abstract

The Fermi Large Area Telescope (LAT) collaboration recently released the updated results of the measurement of the cosmic ray electron (CRE) spectrum and published its first constraints on the CRE anisotropy. With respect to the previous Fermi-LAT results, the CRE spectrum measurement was extended down from 20 to 7 GeV, thus providing a better lever arm to discriminate theoretical models. Here we show that the new data strengthen the evidence for the presence of two distinct electron and positron spectral components. Furthermore, we show that under such hypothesis most relevant CRE and positron data sets are remarkably well reproduced. Consistent fits of cosmic-ray nuclei and antiproton data, which are crucial to validate the adopted propagation setup(s) and to fix the solar modulation potential, are obtained for the Kraichnan and plain-diffusion propagation setups, while the Kolmogorov one is disfavored. We then confirm that nearby pulsars are viable source candidates of the required $e^{\pm }$ extra-component. In that case, we show that the predicted CRE anisotropy is compatible with Fermi-LAT constraints and that a positive detection should be at hand of that observatory. Models assuming that only nearby supernova remnants contribute to the high energy tail of the observed CRE spectrum are in contrast with anisotropy limits.

arXiv comment23 pages, 22 figures. Accepted for publication in Astroparticle Physics. Some of the results presented in this paper have been derived with the DRAGON package which is now public at the website: http://www.desy.de/~maccione/DRAGON/

References in corpus (38)

• The ATNF Pulsar Catalogue
• Propagation of cosmic-ray nucleons in the Galaxy
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
• PAMELA results on the cosmic-ray antiproton flux from 60 MeV to 180 GeV in kinetic energy
• Pulsars as the Sources of High Energy Cosmic Ray Positrons
• Diffuse Galactic continuum gamma rays. A model compatible with EGRET data and cosmic-ray measurements
• Probing the ATIC peak in the cosmic-ray electron spectrum with H.E.S.S
• Measurements of the Cosmic-Ray Positron Fraction From 1 to 50 GeV
• Secondary antiprotons and propagation of cosmic rays in the Galaxy and heliosphere
• Cosmic Rays below Z=30 in a diffusion model: new constraints on propagation parameters
• Fermi LAT observations of cosmic-ray electrons from 7 GeV to 1 TeV
• Detection of 16 Gamma-Ray Pulsars Through Blind Frequency Searches Using the Fermi LAT
• Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact on Interstellar Turbulence and Cosmic Ray Transport
• Cosmic-Ray Nuclei, Antiprotons and Gamma-rays in the Galaxy: a New Diffusion Model
• The origin of the positron excess in cosmic rays
• GALPROP WebRun: an internet-based service for calculating galactic cosmic ray propagation and associated photon emissions
• On possible interpretations of the high energy electron-positron spectrum measured by the Fermi Large Area Telescope
• Fermi-LAT Discovery of Extended Gamma-ray Emission in the Direction of Supernova Remnant W51C
• The Most Likely Sources of High Energy Cosmic-Ray Electrons in Supernova Remnants
• Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment
• Constraints on Dark Matter Annihilation in Clusters of Galaxies with the Fermi Large Area Telescope
• Fermi Large Area Telescope Measurements of the Diffuse Gamma-Ray Emission at Intermediate Galactic Latitudes
• Dark matter interpretation of recent electron and positron data
• Inverse Compton Emission from Galactic Supernova Remnants: Effect of the Interstellar Radiation Field
• High Energy Positrons From Annihilating Dark Matter
• Electron acceleration in SNR and diffuse gamma-rays above 1 GeV
• Unified interpretation of cosmic-ray nuclei and antiproton recent measurements
• Inhomogeneity in the Supernova Remnant Distribution as the Origin of the PAMELA Anomaly
• The distance and radius of the neutron star PSR B0656+14
• Systematic uncertainties on the cosmic-ray transport parameters: Is it possible to reconcile B/C data with delta = 1/3 or delta = 1/2?
• Searches for Cosmic-Ray Electron Anisotropies with the Fermi Large Area Telescope
• Possible causes of a rise with energy of the cosmic ray positron fraction
• A revised Galactic supernova remnant catalogue
• The GALPROP Cosmic-Ray Propagation Code
• The Contribution of Fermi Gamma-Ray Pulsars to the local Flux of Cosmic-Ray Electrons and Positrons
• Positrons from pulsar winds
• The High Energy Cosmic Ray Electron Spectrum measured by Fermi Gamma-Ray Space Telescope: some possible interpretations

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