Pulsars versus Dark Matter Interpretation of ATIC/PAMELA

Abstract

In this paper, we study the flux of electrons and positrons injected by pulsars and by annihilating or decaying dark matter in the context of recent ATIC, PAMELA, Fermi, and HESS data. We review the flux from a single pulsar and derive the flux from a distribution of pulsars. We point out that the particle acceleration in the pulsar magnetosphere is insufficient to explain the observed excess of electrons and positrons with energy E ~ 1 TeV and one has to take into account an additional acceleration of electrons at the termination shock between the pulsar and its wind nebula. We show that at energies less than a few hundred GeV, the flux from a continuous distribution of pulsars provides a good approximation to the expected flux from pulsars in the Australia Telescope National Facility (ATNF) catalog. At higher energies, we demonstrate that the electron/positron flux measured at the Earth will be dominated by a few young nearby pulsars, and therefore the spectrum would contain bumplike features. We argue that the presence of such features at high energies would strongly suggest a pulsar origin of the anomalous contribution to electron and positron fluxes. The absence of features either points to a dark matter origin or constrains pulsar models in such a way that the fluctuations are suppressed. Also we derive that the features can be partially smeared due to spatial variation of the energy losses during propagation.

23 pages, 15 figures, 1 table; v2: minor corrections, references added; v3: 20 pages, 10 figures, 1 table, major changes in presentation, main conclusions unchanged; v4: minor corrections

References in corpus (14)

• Observation of an anomalous positron abundance in the cosmic radiation
• A Theory of Dark Matter
• The ATNF Pulsar Catalogue
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• On possible interpretations of the high energy electron-positron spectrum measured by the Fermi Large Area Telescope
• PAMELA data and leptonically decaying dark matter
• Observation of Pulsed Gamma-rays Above 25 GeV from the Crab Pulsar with MAGIC
• High-energy electron observations by PPB-BETS flight in Antarctica
• The PAMELA and ATIC Excesses From a Nearby Clump of Neutralino Dark Matter
• Discriminating different scenarios to account for the cosmic $e^{\pm }$ excess by synchrotron and inverse Compton radiation
• ATIC, PAMELA, HESS, Fermi and nearby Dark Matter subhalos
• Prospects for Detecting Neutrino Signals from Annihilating/Decaying Dark Matter to Account for the PAMELA and ATIC results
• A new estimate of the Galactic interstellar radiation field between 0.1 microns and 1000 microns
• On discrepancy between ATIC and Fermi data

Cited by in corpus (4)

• On possible interpretations of the high energy electron-positron spectrum measured by the Fermi Large Area Telescope
• ATIC, PAMELA, HESS, Fermi and nearby Dark Matter subhalos
• Galactic Signatures of Decaying Dark Matter
• On discrepancy between ATIC and Fermi data