A model for delayed emission in a very-high energy gamma-ray flare in Markarian 501

TL;DR

This paper models the delayed high-energy gamma-ray emission in a flare from Markarian 501, predicting energy-dependent delays that can be tested with future simultaneous observations, based on a modified SSC model during particle acceleration.

Contribution

It introduces a modified SSC model during particle acceleration to explain energy-dependent photon delays in gamma-ray flares from blazars.

Findings

Predicts a 1-hour delay between 10 GeV and 100 GeV emissions.

Suggests delays can be tested with future GLAST and Cherenkov telescope observations.

Provides a theoretical framework for energy-dependent photon arrival times.

Abstract

Recently, the MAGIC collaboration reported evidence for a delay in the arrival times of photons of different energies during a gamma-ray flare from the blazar Markarian 501 on 2005 July 9. We apply a homogeneous synchrotron self-Compton (SSC) model under the assumption that the blob containing relativistic electrons was observed in its acceleration phase. This modified SSC model predicts the appearance of a gamma-ray flare first at lower energies and subsequently at higher energies. Based on the reported time delay of approx. 240 s between the flare observed at 190 GeV and 2.7 TeV, we predict a delay on the order of 1 h if observed between 10 GeV and 100 GeV. Such delay timescales can be tested in the future by simultaneous flare observations with the Gamma Ray Large Area Space Telescope (GLAST) and Cherenkov telescopes.