Dark matter electron anisotropy: A universal upper limit

Enrico Borriello, Luca MacCione, Alessandro Cuoco

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

We study the dipole anisotropy in the arrival directions of high energy CR electrons and positrons (CRE) of dark matter (DM) origin. We show that this quantity is very weakly model dependent and offers a viable criterion to discriminate among CRE from DM or from local discrete sources, like e.g. pulsars. In particular, we find that the maximum anisotropy which DM can provide is to a very good approximation a universal quantity and, as a consequence, if a larger anisotropy is detected, this would constitute a strong evidence for the presence of astrophysical local discrete CRE sources, whose anisotropy, instead, can be naturally larger than the DM upper limit. We further find that the main source of anisotropy from DM is given by the fluctuation in the number density of DM sub-structures in the vicinity of the observer and we thus devote special attention to the study of the variance in the sub-structures realization implementing a dedicated Montecarlo simulation. Such scenarios will be probed in the next years by Fermi-LAT, providing new hints, or constraints, about the nature of DM.

Original languageEnglish (US)
Pages (from-to)537-546
Number of pages10
JournalAstroparticle Physics
Volume35
Issue number8
DOIs
StatePublished - Mar 2012
Externally publishedYes

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Keywords

  • Cosmic-ray anisotropy
  • Cosmic-ray electrons
  • Dark matter indirect searches

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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