Extracting the Size of the Cosmic Electron-Positron Anomaly
Abstract
We isolated the anomalous part of the cosmic electron-positron flux within a Bayesian likelihood analysis. Using 219 recent cosmic-ray spectral data points, we inferred the values of selected cosmic-ray propagation parameters. In the context of the propagation model coded in GalProp, we found a significant tension between the electron-positron related and the rest of the fluxes. Interpreting this tension as the presence of an anomalous component in the electron-positron related data, we calculated background predictions for PAMELA and Fermi-LAT based on the non-electron-positron related fluxes. We found a deviation between the data and the predicted background even when uncertainties, including systematics, were taken into account. We identified this deviation with the anomalous electron-positron contribution. We briefly compared this model-independent signal to some theoretical results predicting such an anomaly.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2012
- DOI:
- 10.1088/0004-637X/749/2/184
- arXiv:
- arXiv:1106.4138
- Bibcode:
- 2012ApJ...749..184A
- Keywords:
-
- astroparticle physics;
- cosmic rays;
- diffusion;
- Galaxy: general;
- ISM: general;
- methods: statistical;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Cosmology and Extragalactic Astrophysics;
- High Energy Physics - Phenomenology
- E-Print:
- 35 pages with 4 Figures and 2 Tables. References added, accepted for publication in ApJ