Modelling the $\gamma$-ray variability of 3C 273

TL;DR

This paper models the gamma-ray variability of 3C 273 using a time-dependent SSC model, explaining outbursts through changes in electron injection rates and reproducing multi-wavelength spectra during different activity states.

Contribution

It introduces a time-dependent one-zone SSC model that accounts for electron acceleration and injection rate changes to explain gamma-ray outbursts in 3C 273.

Findings

Successfully reproduces gamma-ray outbursts with variable electron injection rates.

Explains multi-wavelength spectra during quiescent and active states.

Demonstrates the importance of time-dependent modeling for blazar variability.

Abstract

We investigate MeV-GeV $\gamma$-ray outbursts in 3C 273 in the frame of a time-dependent one-zone synchrotron self-Compton (SSC) model. In this model, electrons are accelerated to extra-relativistic energy through the stochastic particle acceleration and evolve with the time, nonthermal photons are produced by both synchrotron and inverse Compton scattering of synchrotron photons. Moreover, nonthermal photons during a quiescent are produced by the relativistic electrons in the steady state and those during a outburst are produced by the electrons whose injection rate is changed at some time interval. We apply the model to two exceptionally luminous $\gamma$-ray outbursts observed by the Fermi-LAT from 3C 273 in September, 2009 and obtain the multi-wavelength spectra during the quiescent and during the outburst states, respectively. Our results show that the time-dependent properties of outbursts can be reproduced by adopting the appropriate injection rate function of the electron population.