Hadronic Clues in Quasars Caught by Fermi-LAT

TL;DR

This study investigates whether hadronic processes can explain the high-energy gamma-ray emission from quasars observed by Fermi-LAT, assessing their potential contribution to neutrino fluxes detected by IceCube.

Contribution

It introduces a combined hadronic and leptonic modeling approach to analyze quasar spectral energy distributions, highlighting the necessity of hadronic processes for gamma-ray emission.

Findings

Hadronic processes are needed to explain Fermi-LAT quasar spectra.

Hadronic contribution to IceCube neutrinos is limited.

Multi-wavelength modeling supports mixed emission mechanisms.

Abstract

This work explores whether hadronic processes could be responsible for the high-energy emission seen in quasars identified by the Large Area Telescope (LAT) instrument aboard the Fermi satellite. In contrast to purely leptonic models, this work investigates whether hadronic mechanisms can explain the observed gamma-ray spectra by analyzing the spectral energy distributions (SEDs) of a chosen sample of FSRQs (Flat-Spectrum Radio Quasars). By incorporating both hadronic and leptonic components into their multi-wavelength modeling, we evaluate the model's feasibility to simultaneously describe the data collected by Fermi-LAT and neutrinos detected by IceCube. According to the results, a hadronic contribution would be required to explain the SED of quasars detected by Fermi-LAT. However, their contribution to the neutrino flux detected by IceCube remains understated.