Anisotropies in cosmic rays and microwaves
by
LAPTh Auditorium
LAPTh Auditorium
The directions of charge particles in the interstellar medium are largely randomized by turbulent magnetic fields. Yet, diffusion theories predict a dipole component that encodes information about the distribution of young and nearby sources. A detection of this dipole has been of great interest for dark matter indirect searches and a target for experiments like AMS-02. Observationally, however, the picture is rather different : At PeV energies, the predicted dipole is almost two orders of magnitude larger than the measured one. Furthermore, fluctuations are observed on much smaller scales, while diffusion theories only predict a dipole. I will discuss intermittency effects and the importance of the orientation of the regular magnetic fields in solving these anisotropy problems.
Anisotropies in the arrival directions of primordial microwaves have become a testing ground for cosmological models. While the concordance model is extremely successful for small angular scales, on large scales there are a number of anomalies. I will discuss the role that foreground emission plays on large scales, due to the presence of huge cavities in the interstellar medium, so-called superbubbles. Given the strong coherent and turbulent magnetic fields of these structures, they are of great importance in modeling polarized foregrounds in searches for primordial B-modes.