XRISM/Resolve Reveals the Complex Iron Structure of NGC 7213: Evidence for Radial Stratification between Inner Disk and Broad-line Region

Abstract We present the first high-resolution X-ray spectrum of NGC 7213 obtained with XRISM/Resolve, supported by simultaneous XMM-Newton, NuSTAR, and SOAR optical data. The XRISM spectrum resolves the neutral Fe K α into two components: a narrow core ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">FWHM</mml:mi> <mml:mo>=</mml:mo> <mml:mn>65</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>220</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>240</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">km</mml:mi> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> ), consistent with emission at the dust sublimation radius, and a broader asymmetric line, best described by disklike emission from ∼100 R g . This disk component mirrors the profile of the double-peaked H α line observed in the optical. In addition, we detect broadened Fe xxv and Fe xxvi emission lines, whose inferred locations bridge the gap between the inner disk and the optical broad-line region. The weak narrow Fe K α equivalent width (EW = 32 ± 6 eV) and the absence of a Compton hump imply a low-covering-fraction, Compton-thin torus. Together, these results reveal a radially stratified structure in NGC 7213, spanning nearly 4 orders of magnitude in radius, and place the source in an intermediate-accretion state ( λ Edd = 0.1%–1%), where the inner disk and broad-line region remain, while the torus shows signs of dissipation.

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Journal
The Astrophysical Journal Letters
Published
2025-11-13
DOI
https://doi.org/10.3847/2041-8213/ae18c2
Citations
2
Primary Topic
Astrophysical Phenomena and Observations
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article
Field-Weighted Citation Impact
2.31
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article

XRISM/Resolve Reveals the Complex Iron Structure of NGC 7213: Evidence for Radial Stratification between Inner Disk and Broad-line Region

Fangzheng Shi, C. Pinto, E. Piconcelli, E. Bertola et al.
2 citations
The Astrophysical Journal Letters
Astrophysical Phenomena and Observations
2.31
article

XRISM/Resolve Reveals the Complex Iron Structure of NGC 7213: Evidence for Radial Stratification between Inner Disk and Broad-line Region

Fangzheng Shi, C. Pinto, E. Piconcelli, E. Bertola, F. Panessa, Oluwashina Adegoke, R. Ricci, G. Bruni, G. Lanzuisi, T. Kawamuro, A. Tortosa, Hirofumi Noda, Cláudio Ricci, G. Ponti, F. Ursini, E. Aydi, G. Matt, Satoshi Yamada, C. Vignali, Javier A. García, A. Luminari, Daniel Stern, Hironori Matsumoto, M. Dadina, Michael Eracleous, M. Laurenti, Francesco Tombesi, Ryota Tomaru, G. A. Matzeu, Hirokazu Odaka, F. Nicastro, V. Braito, Elias Kammoun, Yoshihiro Ueda, Teruaki Enoto, Joanna M. Piotrowska, A. Comastri, Peter Boorman, Andrea Marinucci, R. Middei, V. E. Gianolli, Fiona Harrison, Guglielmo Mastroserio, Roberto Serafinelli, E. Nardini, S. Yamada, Yuichi Terashima, A. Tanimoto, S. Bianchi, Shoji Ogawa, Koichi Murakami, Pierpaolo Condó
article en
2 citations

Abstract

Abstract We present the first high-resolution X-ray spectrum of NGC 7213 obtained with XRISM/Resolve, supported by simultaneous XMM-Newton, NuSTAR, and SOAR optical data. The XRISM spectrum resolves the neutral Fe K α into two components: a narrow core ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">FWHM</mml:mi> <mml:mo>=</mml:mo> <mml:mn>65</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>0</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>220</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>240</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:mi mathvariant="normal">km</mml:mi> <mml:mspace width="0.25em"/> <mml:msup> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:math> ), consistent with emission at the dust sublimation radius, and a broader asymmetric line, best described by disklike emission from ∼100 R g . This disk component mirrors the profile of the double-peaked H α line observed in the optical. In addition, we detect broadened Fe xxv and Fe xxvi emission lines, whose inferred locations bridge the gap between the inner disk and the optical broad-line region. The weak narrow Fe K α equivalent width (EW = 32 ± 6 eV) and the absence of a Compton hump imply a low-covering-fraction, Compton-thin torus. Together, these results reveal a radially stratified structure in NGC 7213, spanning nearly 4 orders of magnitude in radius, and place the source in an intermediate-accretion state ( λ Edd = 0.1%–1%), where the inner disk and broad-line region remain, while the torus shows signs of dissipation.

The Astrophysical Journal LettersVol. 994(1)
Kagoshima University (JP), University of Geneva (CH), University of Insubria (IT), University of Rome Tor Vergata (IT), Roma Tre University (IT), California Institute of Technology (US), Texas Tech University (US), Goddard Space Flight Center (US), Pennsylvania State University (US), Jet Propulsion Laboratory (US), Rikkyo University (JP), University of Trento (IT), Tohoku University (JP), Kyoto University (JP), Shanghai Astronomical Observatory (CN), Arcetri Astrophysical Observatory (IT), Astronomical Observatory of Rome (IT), Agenzia Spaziale Italiana (IT), Japan Aerospace Exploration Agency (JP), Istituto Universitario di Studi Superiori di Pavia (IT), Brera Astronomical Observatory (IT), Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna (IT), Max Planck Institute for Extraterrestrial Physics (DE), European Space Astronomy Centre (ES), Institute for Space Astrophysics and Planetology (IT), Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata (IT), Istituto di Radioastronomia di Bologna (IT), Institute of Space and Astronautical Science (JP), Istituto Nazionale di Fisica Nucleare, Sezione di Roma I (IT), Ehime University (JP), Clemson University (US), Catholic University of America (US), National Institute for Astrophysics (IT), Universidad Diego Portales (CL), University of Bologna (IT), The University of Osaka (JP)
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Astrophysical Phenomena and Observations
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