Impact of the Fluctuations in the Extragalactic Background Light on the
  $\gamma$-ray Attenuation of the Quasars
  This work investigates the impact of the extragalactic background light
fluctuations on very high energy $\gamma$-ray spectra from distant Quasars. We
calculate the extragalactic background light spectral energy distribution using
a model that extends those proposed by Razzaque et al. (2009ApJ.697.483R) and
Finke et al. (2010ApJ.712.238F). We introduce a model for fluctuations in the
extragalactic background light based on fluctuations in the star formation rate
density, since these two fluctuations can reasonably be expected to be
correlated. Fluctuations in the star formation rate are estimated from the
semi-analytical galaxy catalogue of Guo et al. (2013MNRAS.428.1351G), we use
his model to derive the resulting opacities for $\gamma$-rays from distant
sources. We determine the mean, lower and upper limits for the scatter of the
star formation rate density, which then allow us to compute corresponding
limits on the extragalactic background light spectrum. We then calculate the
impact of these fluctuations limits on the $\gamma$-ray optical depth. The
model predicts variations of up to $10\%$ between upper and lower limits for
the $\gamma$-ray opacity in the energy range less than $100$ GeV for nearby
sources. The impact is found to be smaller but still significant ($\lesssim
5\%$) for very high energy $\gamma$-rays from distant sources.
