  The nature of the putative torus and the outer geometry of active galactic
nuclei (AGN) are still rather unknown and the subject of active research.
Improving our understanding of them is crucial for developing a physical
picture for the structure of AGN. The main goal of this work is to investigate
the outer geometry of AGN by studying the observed hard X-ray spectrum of
obscured sources. We primarily aim at researching the reflected emission in
these sources. To that end, we analysed archived NuSTAR observations of a
sample of nearby AGN, whose X-ray emission has been found to be heavily
absorbed, with $10^{23}<N_\text{H}<2.5\cdot 10^{23}\text{ cm}^{-2}$; the upper
limit on $N_\text{H}$ was necessary due to the analysis we followed and the
data quality. Fitting their emission with both a phenomelogical and a physical
model, we investigated the relation between reflection and absorption. The
strength of reflected emission, as well as the equivalent width of the Fe
K$\alpha$ line, correlates with the absorption column density, which can be
explained with a clumpy torus origin for the reflection in these sources. The
shape of the observed correlation is found to be well reproduced when the
effects of a clumpy torus with a variable filling factor are simulated. A
similar increase in reflection seems to be featured even by sources with larger
absorption, reaching the Compton thick ($N_\text{H}>1.5\cdot 10^{24}\text{
cm}^{-2}$) regime.

Astrophysics of Galaxies;High Energy Astrophysical Phenomena