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ASTRA Proceedings An open-access journal for refereed proceedings in extraterrestrial research
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Volume 2
ASTRA Proc., 2, 1-3, 2015
https://doi.org/10.5194/ap-2-1-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
ASTRA Proc., 2, 1-3, 2015
https://doi.org/10.5194/ap-2-1-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

  31 Jul 2015

31 Jul 2015

The Local Bubble as a cosmic-ray isotropizer

I. Gebauer1, M. Weinreuter1, S. Kunz1, and D. Gaggero2,3 I. Gebauer et al.
  • 1Karlsruhe Institute of Technology, Institut für Experimentelle Kernphysik, 76131 Karlsruhe, Germany
  • 2SISSA, via Bonomea 265, 34136, Trieste, Italy
  • 3INFN, sezione di Trieste, via Valerio 2, 34127, Trieste, Italy

Abstract. The arrival directions of energetic positrons and electrons convey fundamental information on their origin. PAMELA, and more recently AMS, have measured an anomalous population of energetic positrons, which cannot be explained in standard cosmic ray propagation models. Two possible sources have been extensively discussed: astrophysical point sources, such as local pulsars, and dark matter. In the first case an anisotropy in the flux of energetic particles is expected. Reliable predictions of the level of anisotropy need to account for the Sun's peculiar environment: the Sun resides in the so-called Local Bubble, an underdense region, embedded in a dense wall of molecular clouds. This structure is expected to act as an efficient cosmic-ray isotropizer. Using realistic assumptions on the impact of the Local Bubble on cosmic-ray diffusion, we demonstrate that the Local Bubble can indeed dilute the directional information of energetic positrons and electrons.

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The Sun resides in the so-called Local Bubble, an underdense region, embedded in a dense wall of molecular clouds. This structure is expected to act as an efficient cosmic-ray isotropizer. Using realistic assumptions on the impact of the Local Bubble on cosmic-ray diffusion, we demonstrate that the Local Bubble can dilute the directional information of energetic positrons and electrons in cosmic rays.
The Sun resides in the so-called Local Bubble, an underdense region, embedded in a dense wall of...
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