The viewing angle in AGN SED models: a data-driven analysis
Monthly Notices of the Royal Astronomical Society, vol. 510, pp. 687–707
Abstract
ABSTRACT The validity of the unified active galactic nuclei (AGNs) 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 data bases: 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 3.5, with a median redshift of z ≈ 0.2. 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 does not affect the physical parameter estimates such as star formation rate (SFR) or AGN fractional contribution (fAGN). 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 Zenodo1.
Authors 5
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University of Groningen · Space Research Organisation Netherlands
Affiliation as printed
Kapteyn Astronomical Institute, University of Groningen, Landleven 12, NL-9747 AD Groningen, The Netherlands
SRON Netherlands Institute for Space Research, Landleven 12, NL-9747 AD Groningen, The Netherlands
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University of Groningen · Space Research Organisation Netherlands
Affiliation as printed
Kapteyn Astronomical Institute, University of Groningen, Landleven 12, NL-9747 AD Groningen, The Netherlands
SRON Netherlands Institute for Space Research, Landleven 12, NL-9747 AD Groningen, The Netherlands
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Centre National de la Recherche Scientifique · Aix-Marseille Université · National Centre for Nuclear Research
Affiliation as printed
Aix Marseille Univ. CNRS, CNES, LAM, F-13007 Marseille, France
National Centre for Nuclear Research, Pasteura 7, PL-02-093 Warsaw, Poland
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Affiliation as printed
School of Sciences, European University Cyprus, Diogenes Street, Engomi, 1516 Nicosia, Cyprus
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Affiliation as printed
Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843-4242, USA
George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A&M University, College Station, TX 77843-4242, USA
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