We thank the anonymous referee for his/her constructive report and
helpful comments. We have followed his/her advice in almost all
points, except a few instances, as detailed below. We hope that 
he/she now finds our paper acceptable for publication in the 
HEASA 2015 proceedings.

3 a) The additional space is automatically generated by the PoS
LaTeX macros and is therefore beyond our control. It might be due
to the page setup, with a new section beginning on the next page.

5 f) Indeed, our statement here was misleading. We were focusing
on energies within the Fermi energy range, i.e., energies E ~ 1 GeV.
We have therefore simply replaced \gtrsim 1 GeV by \sim 1 GeV.

6 b) Unfortunately, the plotting routine that we use does not allow 
us to use Italic symbols in the axis labels. 

6 c) We have added an explanatory statement that the highest-energy
bins are very sparsely populated and any spectral features, such as
the empty bin that the referee referred to, are due to the limited
photon statistics. 

8 f) We have decided to leave the figure as is, since we are aiming
at a more general application to radio galaxies, for which we expect
large viewing angles (i.e., \mu ~ 0).

8 g) As we have now specified, also in response to the referee's 
point 7 a), the energy and time binnings were chosen rather arbitrarily,
as a compromise between time- and energy-resolution and photon statistics
in the energy bins that we are most interested in (i.e., in the Fermi
energy range). This led us to slightly different choices for the 
different test simulations.

8 h) We have decided to leave the figure as it is, as we would like 
to illustrate the change of the energy-dependence of the width with
changing R_{ext}. As the referee points out, due to the multi-dimensional
parameter space here, any choice of representation will have is deficiencies.
We feel that the current representation illustrates our point appropriately.

All other points were straightforward to address, and we believe that
no detailed responses are necessary.

Sincerely,

Parisa Roustazadeh 
on behalf of the authors.