The viewing angle in AGN SED models, a data-driven analysis
  The validity of the unified active galactic nuclei (AGN) model has been
challenged in the last decade, especially when different types of AGNs are
considered to only differ in the viewing angle to the torus. We aim to assess
the importance of the viewing angle in classifying different types of Seyfert
galaxies in spectral energy distribution (SED) modelling. We retrieve
photometric data from publicly available astronomical databases: CDS and NED,
to model SEDs with X-CIGALE in a sample of 13 173 Seyfert galaxies located at
redshift range from $z=0$ to $z=3.5$, with a median redshift of $z\approx0.2$.
We assess whether the estimated viewing angle from the SED models reflects
different Seyfert classifications. Two AGN models with either a smooth or
clumpy torus structure are adopted in this paper. We find that the viewing
angle in Type-1 AGNs is better constrained than in Type-2 AGNs. Limiting the
viewing angles representing these two types of AGNs do not affect the physical
parameter estimates such as star-formation rate (SFR) or AGN fractional
contribution ($f_{\rm{AGN}}$). In addition, the viewing angle is not the most
discriminating physical parameter to differentiate Seyfert types. We suggest
that the observed and intrinsic AGN disc luminosity can: i) be used in $z<0.5$
studies to distinguish between Type-1 and Type-2 AGNs, and ii) explain the
probable evolutionary path between these AGN types. Finally, we propose the use
of X-CIGALE for AGN galaxy classification tasks. All data from the 13 173 SED
fits are available at https://doi.org/10.5281/zenodo.5221764
