3C 279 in Outburst in June 2015: A Broadband-SED Study Based on the INTEGRAL Detection

TL;DR

This study analyzes the broadband spectral energy distribution of blazar 3C 279 during its June 2015 outburst, using multiwavelength data to compare leptonic and lepto-hadronic emission models and their implications for jet physics.

Contribution

First simultaneous broadband SED modeling of 3C 279's outburst with detailed comparison of leptonic and lepto-hadronic models.

Findings

Leptonic model requires sub-equipartition magnetic fields.

Lepto-hadronic model achieves equipartition but implies near-Eddington jet power.

Both models fit the data equally well, but suggest different jet physical conditions.

Abstract

Blazars radiate from radio through gamma-ray frequencies thereby being ideal targets for multifrequency studies. Such studies allow constraining the properties of the emitting jet. 3C 279 is among the most notable blazars and therefore subject to extensive multifrequency campaigns. We report the results of a campaign ranging from near-IR to gamma-ray energies of an outburst of 3C 279 in June 2015. The overall spectral energy distribution from near-IR to gamma rays can be well represented by either a leptonic or a lepto-hadronic radiation transfer model. Even though the data are equally well represented by the two models, their inferred parameters challenge the physical conditions in the jet. In fact, the leptonic model requires parameters with a magnetic field far below equipartition with the relativistic particle energy density. On the contrary, equipartition may be achieved with the lepto-hadronic model, which however implies an extreme total jet power close to Eddington luminosity.