A New Hope for AGN SED fitting: X-ray spectral analysis of 12MGS AGN with the C2PO-Torus model
9 affiliations
- 1Department of Astronomy, University of Cape Town , Private Bag X3, Rondebosch 7701 ,
- 2Inter-University Institute for Data Intensive Astronomy, University of Cape Town , Private Bag X3, Rondebosch 7701 ,
- 3INAF – Istituto di Radioastronomia , via Piero Gobetti 101, I-40129 Bologna ,
- 4INAF – Osservatorio di Astrofisica e Scienza dello Spazio (OAS) , via Piero Gobetti 93/3, I-40129 Bologna ,
- 5Dipartimento di Fisica e Astronomia (DIFA) Augusto Righi, Università di Bologna , via Gobetti 93/2, I-40129 Bologna ,
- 6Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics , Clemson, SC 29634 ,
- 7INAF – Osservatorio Astronomico di Trieste , via Tiepolo 11, I-34131 Trieste ,
- 8IFPU, Institute for Fundamental Physics of the Universe , via Beirut 2, I-34014 Trieste ,
- 9INAF – Osservatorio Astrofisico di Arcetri , Largo E. Fermi 5, I-50125 Firenze ,
Abstract
In this paper, we present the results of comprehensive, broad-band X-ray spectral analysis of a subsample of 43 mid-infrared (IR) selected star-forming active galactic nuclei (AGN). We analysed archival NuSTAR, Chandra, and XMM–Newton data, and present the first pointed X-ray observation of IRASF03450+0055. We introduce a new physically based X-ray spectral model, C2PO-Torus, based on a two-phase clumpy torus geometry. It is designed to provide constraints on physical parameters of the torus that can be directly linked to the parameters of the AGN model SKIRTOR. This model will allow us to exploit the synergies between the X-ray and IR regimes, place stronger constraints on the torus properties, and improve spectral energy distribution (SED) fitting by providing priors for the SKIRTOR parameters. We compare the results from the C2PO-Torus fitting to those obtained from traditional models, finding that it is an extremely effective tool for fitting a wide variety of X-ray spectra. We observe that our sample closely follows the established L[O small III]− LX AGN relation, while presenting an IR and Radio excess with respect to the LX − L12 μ m and LX− L1.4 GHz AGN relations at low luminosities (L2−10 keV lt 1041.5 erg s−1). We believe that this excess is due to contamination from star formation related emission. We anticipate that the C2PO-Torus model will aid substantially in completing full-spectrum SED fitting of this sample, allowing us to properly disentangle the different emission components of these objects, which are local analogues of AGN at Cosmic Noon.
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BibTeX
@article{gilbert2026hope,
title = {{A New Hope for AGN SED fitting: X-ray spectral analysis of 12MGS AGN with the C2PO-Torus model}},
author = {Carys J E Gilbert and Lucia Marchetti and Luigi Barchiesi and Mattia Vaccari and Cristian Vignali and Stefano Marchesi and Francesca Pozzi and Francesco Salvestrini and Anna Feltre and Malebo Moloko and Carlotta Gruppioni},
journal = {Monthly Notices of the Royal Astronomical Society},
year = {2026},
month = oct,
doi = {10.1093/mnras/stag1873},
url = {https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1873/8859312},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - A New Hope for AGN SED fitting: X-ray spectral analysis of 12MGS AGN with the C2PO-Torus model
AU - Carys J E Gilbert
AU - Lucia Marchetti
AU - Luigi Barchiesi
AU - Mattia Vaccari
AU - Cristian Vignali
AU - Stefano Marchesi
AU - Francesca Pozzi
AU - Francesco Salvestrini
AU - Anna Feltre
AU - Malebo Moloko
AU - Carlotta Gruppioni
PY - 2026
DA - 2026/10/01
JO - Monthly Notices of the Royal Astronomical Society
DO - 10.1093/mnras/stag1873
UR - https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1873/8859312
AB - In this paper, we present the results of comprehensive, broad-band X-ray spectral analysis of a subsample of 43 mid-infrared (IR) selected star-forming active galactic nuclei (AGN). We analysed archival NuSTAR, Chandra, and XMM–Newton data, and present the first pointed X-ray observation of IRASF03450+0055. We introduce a new physically based X-ray spectral model, C2PO-Torus, based on a two-phase clumpy torus geometry. It is designed to provide constraints on physical parameters of the torus that can be directly linked to the parameters of the AGN model SKIRTOR. This model will allow us to exploit the synergies between the X-ray and IR regimes, place stronger constraints on the torus properties, and improve spectral energy distribution (SED) fitting by providing priors for the SKIRTOR parameters. We compare the results from the C2PO-Torus fitting to those obtained from traditional models, finding that it is an extremely effective tool for fitting a wide variety of X-ray spectra. We observe that our sample closely follows the established L_[O small III]− L_X AGN relation, while presenting an IR and Radio excess with respect to the L_X − L_12 μ m and L_X− L_1.4 GHz AGN relations at low luminosities (L_2−10 keV lt 10^41.5 erg s^−1). We believe that this excess is due to contamination from star formation related emission. We anticipate that the C2PO-Torus model will aid substantially in completing full-spectrum SED fitting of this sample, allowing us to properly disentangle the different emission components of these objects, which are local analogues of AGN at Cosmic Noon.
SN - 0035-8711
SN - 1365-2966
ER -