Detection potential of the KM3NeT detector for high-energy neutrinos from the Fermi bubbles

Abstract

A recent analysis of the Fermi Large Area Telescope data provided evidence for a high-intensity emission of high-energy gamma rays with a E −2 spectrum from two large areas, spanning 50 • above and below the Galactic centre (the "Fermi bubbles"). A hadronic mechanism was proposed for this gamma-ray emission making the Fermi bubbles promising source candidates of high-energy neutrino emission. In this work Monte Carlo simulations regarding the detectability of high-energy neutrinos from the Fermi bubbles 4 with the future multi-km 3 neutrino telescope KM3NeT in the Mediterranean Sea are presented. Under the hypothesis that the gamma-ray emission is completely due to hadronic processes, the results indicate that neutrinos from the bubbles could be discovered in about one year of operation, for a neutrino spectrum with a cutoff at 100 TeV and a detector with about 6 km 3 of instrumented volume. The effect of a possible lower cutoff is also considered.

Neutrino events at IceCube and the Fermi bubbles

“…The FB signal will be strongly substantiated by a northern hemisphere detector like the future Km3Net [33], which will be at a nearly optimal location to look for tracklike events from the bubbles [31]. More than 300 events per decade are expected for E 0 ¼ 10 PeV.…”

“…For the same parameters, a significance of 3σ would be obtained with about seven years of running time. The time needed for discovery might be shorter with the use of detailed statistical analyses of the spatial correlation with the bubbles, and/or if a compatible excess is observed in track events at a detector in the Northern hemisphere [31,33]. For the most conservative spectrum, E 0 ¼ 1 PeV, the background is Fig.…”

“…In the baryonic hypothesis, the gamma ray flux from the bubbles should have a neutrino counterpart of similar magnitude [29,31], which should be detectable in muon tracks at a Km 3 detector in the northern hemisphere [31]. Dedicated experimental work on this is in progress [32,33], and an upper limit has been placed by the ANTARES collaboration (see Fig. 2) [32].…”

Recent results from the ANTARES neutrino telescope

“…Limits were placed on possible fluxes of neutrinos for various assumptions on the energy cut-off at the source. As stated in [15], these limits are close to the theoretical expectations, meaning that the hadronic origin of the observed gamma-rays from the FBs could be probed with the full ANTARES data set, or after one year of data taking with KM3NeT [16], the next generation neutrino telescope to be built in the Mediterranean Sea.…”

The KM3NeT deep-sea neutrino telescope

“…Assuming a hadronic mechanism for the gamma ray production from the Fermi bubbles, a high energy neutrino flux is also expected. If the gamma production is completely due to hadronic processes, the results of Monte Carlo simulations [6] indicate that a discovery is possible in about one year of KM3NeT operation.…”