Supermassive Black Hole Winds in X-rays: SUBWAYS. VI. Interplay between the soft X-ray excess and ultrafast outflows
Year: 2026
Type: article
Abstract: We present the first systematic broadband and multiwavelength investigation of the interplay between the soft X-ray excess (SE), ultrafast outflows (UFOs), and warm absorbers (WAs) in 21 active galactic nuclei (AGNs; 0.1 łeq z łeq 0.4) from the SUBWAYS project. We combined simultaneous or quasi-simultaneous UV, optical, and X-ray photometry and spectroscopy of XMM- Newton (EPIC pn and OM), νstar, and Hubble Space Telescope. We investigated the presence and physical origin of the SE by modeling the data within the two-coronae paradigm, where a warm, optically thick corona (WC) produces the optical/UV--soft X-ray emission and a hot, optically thin corona generates the hard X-ray continuum. We also tested a hybrid model consisting of a relativistic reflection component in addition to the two-coronae emission. The optical/UV coverage allowed us to directly constrain the seed photon temperature of the Comptonization process, with values spanning 0.1--5.5 eV. The two-coronae model provides a consistent description of the broadband emission, with WC electron temperatures of kT_ ̊m e ≃ 0.1–0.9 keV and photon indices of Γ ≥ 2, which are consistent with previous studies. However, nine of the 21 AGNs require the hybrid configuration, indicating that the SE arises from a combination of processes whose relative contribution varies among sources. This is particularly evident in AGNs hosting UFOs, where four out of the seven observations favor the hybrid model. Compared with no-UFO sources, UFO hosts show lower WC electron temperatures, harder hot corona spectra, and positive hardness ratios. However, these trends should be interpreted cautiously given the limited sample size and their dependence on spectral parameters and instrumental response. The AGNs with and without WAs showed no significant differences. Finally, our correlation analysis revealed several links between WC, SE, AGN, and UFO properties, including correlations of the amplification factor with WC temperature, of the WC optical depth with the hardness ratio, and of the WC slope and optical depth with the UV luminosity, as well as a tentative anticorrelation between WC optical depth and UFO outflow velocity.
Source: Astronomy and Astrophysics
Authors: V. E. Gianolli, P-O. Petrucci, S. Bianchi, M. Brusa, G. Lanzuisi, G. A. Matzeu, M. Mehdipour, F. Ursini, N. Torres-Albà, E. Amenta, E. Behar, L. Borrelli, M. Cappi, A. Comastri, E. Costantini, M. Dadina, B. De Marco, A. De Rosa, M. Giustini, S. Kraemer, G. Kriss, Y. Krongold, A. L. Longinotti, S. Mathur, R. Middei, G. Miniutti, E. Nardini, S. Peluso, E. Piconcelli, G. Ponti, R. Serafinelli, F. Tombesi, A. Tortosa, C. Vignali, I. Cox, S. Marchesi, M. Parra, M. Ajello, T. Mukherjee, I. Pal, P. Patel, A. Pizzetti, D. Sengupta, R. Silver, X. Zhao
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: National Aeronautics and Space Administration, Space Telescope Science Institute, Centre National d’Etudes Spatiales, Israel Science Foundation, Centre National de la Recherche Scientifique, Istituto Nazionale di Astrofisica, Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México, European Regional Development Fund, Agencia Estatal de Investigación
OpenAlex ID: W7223156875