On the Origin of Gamma-ray Flares from Bright Fermi Blazars

TL;DR

This study investigates the origins of gamma-ray flares in bright blazars using a novel SED fitting method, revealing correlations between gamma-ray flux and spectral features, and proposing magnetic reconnection as a key mechanism.

Contribution

Introduces a new spectral energy distribution fitting technique to analyze gamma-ray flares in blazars, linking flare characteristics to electron spectral hardening and Doppler factor changes.

Findings

Gamma-ray flux correlates with SED peak separation and Compton dominance.

Spectral hardening and Doppler boosting can explain flare observations.

Magnetic reconnection may power the gamma-ray flares.

Abstract

The origin of gamma-ray flares observed from blazars is one of the major mysteries in jet physics. We have attempted to address this problem following a novel spectral energy distribution (SED) fitting technique that explored the flaring patterns identified in the broadband SEDs of two gamma-ray bright blazars 3C 279 (z=0.54) and 3C 454.3 (z=0.86), using near-simultaneous radio-to-gamma-ray observations. For both sources, the gamma-ray flux strongly correlates with the separation of the SED peaks and the Compton dominance. We propose that spectral hardening of the radiating electron population and/or enhancement of the Doppler factor can naturally explain these observations. In both cases, magnetic reconnection may play a pivotal role in powering the luminous gamma-ray flares.