Leptohadronic parameters of 324 blazars

This amounts to 34% of all FSRQs in the latest Fermi catalog. We demonstrate that the optical and gigaelectronvolt gamma-ray broadband features are generally well described by electron emission, which helps for the location of the emission region relative to the central black hole to be constrained. For 33% of the blazars in our sample, a description of the observed X-ray spectrum benefits from an additional component from proton interactions, in agreement with recent studies of individual IceCube candidate blazars.

We show that, on average, blazars that are brighter in gigaelectronvolt gamma rays have a higher neutrino production efficiency but a lower best-fit baryonic loading. The predicted neutrino luminosity shows a positive correlation both with the observed flux of gigaelectronvolt gamma rays and with the predicted flux of megaelectronvolt gamma rays. We also estimate the diffuse neutrino flux from gamma-ray blazars by extrapolating the result to the Fermi population, and we show that it may be at the level of ~20% of the diffuse neutrino flux observed by IceCube, in agreement with current limits from stacking analyses.

We discuss the implications of our results for future neutrino searches and suggest promising sources for potential detections.