IceCube and HAWC constraints on very-high-energy emission from the Fermi bubbles

Abstract

The nature of the $\gamma$-ray emission from the \emph{Fermi} bubbles is unknown. Both hadronic and leptonic models have been formulated to explain the peculiar $\gamma$-ray signal observed by the Fermi-LAT between 0.1-500~GeV. If this emission continues above $\sim$30~TeV, hadronic models of the \emph{Fermi} bubbles would provide a significant contribution to the high-energy neutrino flux detected by the IceCube observatory. Even in models where leptonic $\gamma$-rays produce the \emph{Fermi} bubbles flux at GeV energies, a hadronic component may be observable at very high energies. The combination of IceCube and HAWC measurements have the ability to distinguish these scenarios through a comparison of the neutrino and $\gamma$-ray fluxes at a similar energy scale. We examine the most recent four-year dataset produced by the IceCube collaboration and find no evidence for neutrino emission originating from the \emph{Fermi} bubbles. In particular, we find that previously suggested excesses are consistent with the diffuse astrophysical background with a p-value of 0.22 (0.05 in an extreme scenario that all the IceCube events that overlap with the bubbles come from them). Moreover, we show that existing and upcoming HAWC observations provide independent constraints on any neutrino emission from the \emph{Fermi} bubbles, due to the close correlation between the $\gamma$-ray and neutrino fluxes in hadronic interactions. The combination of these results disfavors a significant contribution from the \emph{Fermi} bubbles to the IceCube neutrino flux.

9 pages, 4 figures, to appear in PRD

References in corpus (9)

• Giant Gamma-ray Bubbles from Fermi-LAT: AGN Activity or Bipolar Galactic Wind?
• The Spectrum and Morphology of the Fermi Bubbles
• The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays
• Simultaneous Acceleration of Protons and Electrons at Nonrelativistic Quasiparallel Collisionless Shocks
• Extended Anomalous Foreground Emission in the WMAP 3-Year Data
• A Galactic Halo Origin of the Neutrinos Detected by IceCube
• Search for Very High Energy Gamma Rays from the Northern $\text{Fermi}$ Bubble Region with HAWC
• A Hadronic-Leptonic Model for the Fermi Bubbles: Cosmic-Rays in the Galactic Halo and Radio Emission
• Multi-wavelength Emission from the Fermi Bubble I. Stochastic acceleration from Background Plasma

Cited by in corpus (11)

• A Combined Astrophysical and Dark Matter Interpretation of the IceCube HESE and Throughgoing Muon Events
• Can winds driven by active galactic nuclei account for the extragalactic gamma-ray and neutrino backgrounds?
• Unveiling the Origin of the Fermi Bubbles
• Constraints on the models of the origin of high-energy astrophysical neutrinos
• Constraints on very high energy gamma-ray emission from the Fermi Bubbles with future ground-based experiments
• Unveiling the Fermi Bubbles origin with MeV photon telescopes
• Fermi bubbles: high latitude X-ray supersonic shell
• Emission from hadronic and leptonic processes in galactic jet-driven bubbles
• Galactic Centre as an efficient source of cosmic rays
• Multi-messenger Implications of Sub-PeV Diffuse Galactic Gamma-Ray Emission
• Multi-wavelength emission from leptonic processes in ageing galaxy bubbles