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. (C) 2009 Elsevier B.V. All rights reserved.

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, Nicola; Kamae, T.; Latronico, L.; Longo, F.; Mazziotta, M. N.; Moiseev, A. A.; Morselli, A.; Ormes, J. F.; Pesce Rollins, M.; Pohl, M.; Razzano, M.; Sgro, C.; Spandre, G.; Stephens, T. E.. - In: ASTROPARTICLE PHYSICS. - ISSN 0927-6505. - 32:2(2009), pp. 140-151. [10.1016/j.astropartphys.2009.07.003]

On possible interpretations of the high energy electron-positron spectrum measured by the Fermi Large Area Telescope

GIGLIETTO, Nicola;
2009-01-01

Abstract

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. (C) 2009 Elsevier B.V. All rights reserved.
2009
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, Nicola; Kamae, T.; Latronico, L.; Longo, F.; Mazziotta, M. N.; Moiseev, A. A.; Morselli, A.; Ormes, J. F.; Pesce Rollins, M.; Pohl, M.; Razzano, M.; Sgro, C.; Spandre, G.; Stephens, T. E.. - In: ASTROPARTICLE PHYSICS. - ISSN 0927-6505. - 32:2(2009), pp. 140-151. [10.1016/j.astropartphys.2009.07.003]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/84
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