On Possible Interpretations of the High Energy Electron-Positron Spectrum Measured by the Fermi Large Area Telescope

Grasso, D. ; Profumo, S. ; Strong, A.W. ; Baldini, L. ; Bellazzini, R. ; Bloom, E.D. ; Bregeon, J. ; Di Bernardo, G. ; Gaggero, D. ; Giglietto, N. ; Kamae, T. ; Latronico, L. ; Longo, F. ; Mazziotta, M.N. ; Moiseev, A.A. ; Morselli, A. ; Ormes, J.F. ; Pesce-Rollins, M. ; P

关键词: ACCURACY;    ANISOTROPY;    ANNIHILATION;    CUMULATIVE RADIATION EFFECTS;    DATA;    ENERGY;    NONLUMINOUS MATTER;    PARTICLES;    POSITRONS;    PULSARS;    TELESCOPES Astrophysics;    OTHER;   

DOI  :  10.2172/952979
RP-ID  :  SLAC-PUB-13617
PID  :  OSTI ID: 952979
Others  :  Other: arXiv:0905.0636
Others  :  TRN: US1000854

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来源: SciTech Connect

【 摘 要 】

The Fermi-LAT experiment recently reported high precision measurements of the spectrum of cosmic-ray electrons-plus-positrons (CRE) between 20 GeV and 1 TeV. The spectrum shows no prominent spectral features, and is significantly harder than that inferred from several previous experiments. Here we discuss several interpretations of the Fermi results based either on a single large scale Galactic CRE component or by invoking additional electron-positron primary sources, e.g. nearby pulsars or particle Dark Matter annihilation. We show that while the reported Fermi-LAT data alone can be interpreted in terms of a single component scenario, when combined with other complementary experimental results, specifically the CRE spectrum measured by H.E.S.S. and especially the positron fraction reported by PAMELA between 1 and 100 GeV, that class of models fails to provide a consistent interpretation. Rather, we find that several combinations of parameters, involving both the pulsar and dark matter scenarios, allow a consistent description of those results. We also briefly discuss the possibility of discriminating between the pulsar and dark matter interpretations by looking for a possible anisotropy in the CRE flux.