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

Résumé fourni par la source

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 ( FWHM = 65 0 − 220 + 240 km s − 1 ), 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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