High-energy neutrino fluxes from AGN populations inferred from X-ray surveys

Abstract

High-energy neutrinos and photons are complementary messengers, probing violent astrophysical processes and structural evolution of the Universe. X-ray and neutrino observations jointly constrain conditions in active galactic nuclei (AGN) jets: their baryonic and leptonic contents, and particle production efficiency. Testing two standard neutrino production models for local source Cen A (Koers & Tinyakov 2008; Becker & Biermann 2009), we calculate the high-energy neutrino spectra of single AGN sources and derive the flux of high-energy neutrinos expected for the current epoch. Assuming that accretion determines both X-rays and particle creation, our parametric scaling relations predict neutrino yield in various AGN classes. We derive redshift-dependent number densities of each class, from Chandra and Swift/BAT X-ray luminosity functions (Silverman et al. 2008;Ajello et al. 2009). We integrate the neutrino spectrum expected from the cumulative history of AGN (correcting for cosmological and source effects, e.g. jet orientation and beaming). Both emission scenarios yield neutrino fluxes well above limits set by IceCube (by " 4-10 6ˆa t 1 PeV, depending on the assumed jet models for neutrino production). This implies that: (i) Cen A might not be a typical neutrino source as commonly assumed; (ii) both neutrino production models overestimate the efficiency; (iii) neutrino luminosity scales with accretion power differently among AGN classes and hence does not follow X-ray luminosity universally; (iv) some AGN are neutrino-quiet (e.g. below a power threshold for neutrino production); (v) neutrino and X-ray emission have different duty cycles (e.g. jets alternate between baryonic and leptonic flows); or (vi) some combination of the above.

R -parity violating supersymmetric explanation of the anomalous events at ANITA

“…According to Refs. [49][50][51][52][53], such a large flux could in principle come from a transient point source, such as blazar, supernova burst, gammaray burst, or starburst galaxy, in the northern sky. In Refs.…”

The High Energy View of FR0 Radio Galaxies

“…These relativistic protons can interact with the soft synchrotron radiation and produce electromagnetic cascades above several tens of TeV and be responsible for the neutrino production. FR 0s have been recently proposed as cosmic neutrino emitters because of their γ-ray emission [83,105].…”

Active Galactic Nuclei as High-Energy Neutrino Sources

“…Photohadronic production of high-energy neutrinos in jets of radio galaxies has been discussed in the literature. [64][65][66] However, as in the blazar case, predicted neutrino spectra are too hard to explain the IceCube data for a flat CR spectrum.…”