Towards a consistent framework of determining active galactic nucleus contribution fraction and host galaxy properties
Abstract
Decomposing active galactic nucleus (AGN) emission from host-galaxy light is essential for identifying AGN-dominated systems and accurately deriving host-galaxy physical properties. However, estimating AGN contributions from multi-wavelength photometry remains challenging due to inherent parameter degeneracies in spectral energy distribution (SED) fitting. In this work, we establish a unified framework for estimating AGN contribution fractions and host-galaxy properties by combining complementary diagnostics: SED decomposition with two independent fitting codes, CIGALE and GRAHSP, and deep-learning-based imaging decomposition. We apply this framework to galaxies in the COSMOS-Web field using multi-wavelength photometry from the ultraviolet to the far-infrared. We calculate the AGN contribution fraction in the JWST/NIRCam F150W filter and compare the SED-derived estimates with independent AGN fractions obtained from deep-learning image decomposition. Our results reveal significant degeneracies in current SED-fitting approaches based on empirical or theoretical AGN templates and demonstrate that incorporating independent morphological information can help break these degeneracies and improve the reliability of AGN and host-galaxy property estimates.
Authors 6
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Affiliation as printed
Kapteyn Astronomical Institute , University of Groningen , Postbus 800 , 9700 AV Groningen , The Netherlands
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University of Groningen · Space Research Organisation Netherlands
Affiliation as printed
Kapteyn Astronomical Institute , University of Groningen , Postbus 800 , 9700 AV Groningen , The Netherlands
SRON Netherlands Institute for Space Research , Landleven 12 , 9747 AD Groningen , The Netherlands
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Space Research Organisation Netherlands
Affiliation as printed
SRON Netherlands Institute for Space Research , Landleven 12 , 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 Université , CNRS , CNES , LAM , Marseille , France
National Centre for Nuclear Research , Pasteura 7 , 02-093 , Warsaw , Poland
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Astronomical Observatory of Capodimonte · National Institute for Astrophysics
Affiliation as printed
INAF -Osservatorio Astronomico di Capodimonte Salita Moiariello 16 , 80131 , Napoli , Italy
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