High-energy neutrinos from cosmic ray interactions in the Local Bubble
Abstract
A surprisingly large flux of extraterrestrial high-energy neutrinos was discovered by the IceCube experiment. While the flux of muon neutrinos with energies E>100 TeV is consistent with the extragalactic gamma-ray background (EBL) determined by Fermi-LAT, the softer component of the cascade neutrino flux at E<100 TeV is larger than expected. Moreover, a gamma-ray excess at high Galactic latitudes at energies E>300 GeV was found in the data of Fermi-LAT. The gamma-ray excess at TeV energies and the neutrino excess at E<100 TeV may have a common Galactic origin. In this work, we study the possibility that both excesses are caused by interactions of cosmic rays (CRs) with energies up to PeV in the wall of the Local Bubble. Source of these CRs may be a recent nearby source like Vela. We show that such a scenario can explain the observed CR flux around the knee, while CR interactions in the bubble wall can generate a substantial fraction of the observed astrophysical high-energy neutrino flux below few × 100 TeV.