Hamburg 2016 – wissenschaftliches Programm

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T: Fachverband Teilchenphysik

T 83: Kosmische Strahlung

T 83.6: Vortrag

Mittwoch, 2. März 2016, 18:05–18:20, VMP9 SR 30

Bubbles, Superbubbles and their impact on cosmic ray transport — •Matthias Weinreuter, Iris Gebauer, Wim de Boer, and Alexander Neumann — KIT, Karlsruhe

The Fermi-LAT data on diffuse gamma rays show variations in the gamma ray intensity, which are linked to either variations in the gas density or variations in the cosmic ray density. Such small scale variations are not modeled in current state-of-the-art models for galactic cosmic ray propagation. Inhomogeneities in the interstellar material can be formed by cavities like the so-called Local Bubble, an underdense region surrounding our Sun, which was created by several supernova explosions in the past. We show that the Local Bubble can have a strong impact on the cosmic ray energy spectra and density. In particular, it enhances cosmic ray scattering in the surrounding molecular cloud complexes and can significantly distort the cosmic ray arrival directions. We briefly discuss the consequences for pulsar searches in energetic positrons and electrons. By making simple assumptions on the level of inhomogeneity in the interstellar medium we investigate if the observed variations in the diffuse gamma ray emission can indeed be explained by cavities similar to the Local Bubble.