On the relation between the neutrino flux from Centaurus A and the associated diffuse neutrino flux

TL;DR

This paper explores the relationship between neutrino flux from Centaurus A and the diffuse neutrino background, suggesting that if Cen A is a typical source, the diffuse flux should be significantly larger, impacting detection expectations.

Contribution

It introduces a method to relate Cen A's neutrino flux to the diffuse background, constraining source models based on observed UHECRs and neutrino flux ratios.

Findings

Diffuse neutrino flux is estimated to be 200-5000 times larger than Cen A's flux.

Some UHECR-related neutrino production models exceed current observational limits.

Detection of neutrinos from Cen A without diffuse flux implies an exceptionally efficient source.

Abstract

Based on recent results obtained by the Pierre Auger Observatory (PAO), it has been hypothesized that Centaurus A (Cen A) is a source of ultra-high-energy cosmic rays (UHECRs) and associated neutrinos. We point out that the diffuse neutrino flux may be used to constrain the source model if one assumes that the ratio between the UHECR and neutrino fluxes outputted by Cen A is representative for other sources. Under this assumption we investigate the relation between the neutrino flux from Cen A and the diffuse neutrino flux. Assuming furthermore that Cen A is the source of two UHECR events observed by PAO, we estimate the all-sky diffuse neutrino flux to be ~200-5000 times larger than the neutrino flux from Cen A. As a result, the diffuse neutrino fluxes associated with some of the recently proposed models of UHECR-related neutrino production in Cen A are above existing limits. Regardless of the underlying source model, our results indicate that the detection of neutrinos from Cen A without the accompanying diffuse flux would mean that Cen A is an exceptionally efficient neutrino source.