Delving into the depths of NGC 3783 with XRISM

I. Kinematic and ionization structure of the highly ionized outflows

¹ Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
² SRON Netherlands Institute for Space Research, Niels Bohrweg 4, 2333 CA Leiden, The Netherlands
³ Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, The Netherlands
⁴ Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
⁵ University of Maryland College Park, Department of Astronomy, College Park, MD 20742, USA
⁶ NASA Goddard Space Flight Center (GSFC), Greenbelt, MD 20771, USA
⁷ Center for Research and Exploration in Space Science and Technology, NASA GSFC (CRESST II), Greenbelt, MD 20771, USA
⁸ Department of Physics, Technion, Haifa 32000, Israel
⁹ MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
¹⁰ ESA European Space Astronomy Centre (ESAC), Camino Bajo del Castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain
¹¹ Department of Physics and Astronomy, James Madison University, Harrisonburg, VA 22807, USA
¹² ESA European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands
¹³ Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
¹⁴ Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109, USA
¹⁵ Science Research Education Unit, University of Teacher Education Fukuoka, Munakata, Fukuoka 811-4192, Japan
¹⁶ Astronomical Institute, Tohoku University, 6-3 Aramakiazaaoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan
¹⁷ Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Kanagawa 252-5210, Japan
¹⁸ Graduate School of Science and Engineering, Kagoshima University, Kagoshima 890-8580, Japan

^⋆ Corresponding author: missagh.mehdipour@gmail.com

Received: 22 May 2025
Accepted: 11 June 2025

Abstract

We present our study of the X-Ray Imaging and Spectroscopy Mission (XRISM) observation of the Seyfert-1 galaxy NGC 3783. XRISM’s Resolve microcalorimeter has enabled, for the first time, a detailed characterization of the highly ionized outflows in this active galactic nucleus. Our analysis constrains their outflow and turbulent velocities, along with their ionization parameter (ξ) and column density (N_H). The high-resolution Resolve spectrum reveals a distinct series of Fe absorption lines between 6.4 and 7.8 keV, ranging from Fe XVIII to Fe XXVI. At lower energies (1.8−3.3 keV), absorption features from Si, S, and Ar are also detected. Our spectroscopy and photoionization modeling of the time-averaged Resolve spectrum uncovers six outflow components, five of which exhibit relatively narrow absorption lines with outflow velocities ranging from 560 to 1170 km s⁻¹. In addition, a broad absorption feature is detected, which is consistent with Fe XXVI outflowing at 14 300 km s⁻¹ (0.05 c). The kinetic luminosity of this component is 0.8−3% of the bolometric luminosity. Our analysis of the Resolve spectrum shows that more highly ionized absorption lines are intrinsically broader than those of lower-ionization species, indicating that the turbulent velocity of the six outflow components (ranging from 0 to 3500 km s⁻¹) increases with ξ. Furthermore, we find that the column density (N_H) of the outflows generally declines with the ionization parameter up to log ξ = 3.2 but rises beyond this point, suggesting a complex ionization structure. The absorption profile of the Fe XXV resonance line is intriguingly similar to UV absorption lines (Lyα and C IV) observed by the Hubble Space Telescope, from which we infer that the outflows are clumpy in nature. Our XRISM/Resolve results from lower- and higher-ionization regimes support a “hybrid wind” scenario in which the observed outflows have multiple origins and driving mechanisms. We explore various interpretations of our findings within active galactic nucleus wind models.