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Abstract We present an analysis of the temperature structure of the Perseus cluster atmosphere using X-Ray Imaging and Spectroscopy Mission … (voir plus)(XRISM) Resolve observations. The average temperature rises from 3.3 keV near the nucleus of NGC 1275 to 8 keV at 10′ (210 kpc), which is consistent with Chandra and XMM measurements. The velocity and velocity dispersion profiles are broadly consistent with those in XRISM Collaboration et al. While the gas at altitudes beyond ∼60 kpc can be modeled as a single temperature plasma, we find evidence for more than one gas phase in the inner ∼60 kpc. The hotter gas component, traced primarily by the Fe He α line, has a velocity dispersion of ≲140 km s −1 . We detect a cooler, ∼1.87–2.43 keV, gas component with a velocity dispersion of ∼300–400 km s −1 , a bulk velocity of ∼21–213 km s −1 with respect to the central galaxy, and a mass of 8 × 10 9 –13 × 10 10 M ⊙ . These ranges reflect large systematic uncertainties associated with modeling spatial-spectral mixing and the bright central point source. Potential low energy gain variations may add additional uncertainties. The cooler component is identified by broad wings in prominent emission lines, most notably S Ly α and Fe He α . This cooler component’s Mach number ∼0.73–0.96 and nonthermal pressure fraction of ∼22.9%–33.7% are much higher than found for the hotter gas. The cooler gas may be associated with merging halos along the line of sight, which formed the cool, sloshing spiral and/or cooling gas being disturbed by the radio jets and lobes.
Abstract We analyze new high-spectral-resolution Spectromètre Imageur à Transformée de Fourier pour l’Etude en Long et en Large de raie… (voir plus)s d’Emission (SITELLE) observations ( R = λ /Δ λ = 7000) of the filamentary nebula surrounding NGC 1275, the central galaxy of the Perseus Cluster. We present here analysis of the [S ii ] λ 6716 and [S ii ] λ 6731 emission-line doublet, using its ratio to determine the electron density of the optically emitting filaments. We compare these measurements with electron densities derived from deep Chandra X-ray observations of the intracluster medium (ICM) to determine if any correlations in density can be found. We report the detection of a clear dichotomy between the outer filaments, displaying on average lower [S ii ] emission-line ratios of ∼1.1, and the inner filaments, displaying higher ratios of ∼1.3. These results indicate that most of the gaseous filaments lie close to the low-density threshold for the density measurement of ∼10 2 cm −3 . Using radial profiles, we find that the inner filaments have a roughly constant density, whereas the ICM density decreases with radius. In the outer filaments, we observe hints of local connections between the densities of the ICM and optical filaments, but no clear correlation seems to be observed overall. We also combined these density measurements with cold molecular CO gas observations to derive a relationship between temperature, density, and pressure for the multiphase environment surrounding NGC 1275. Finally, we investigated potential models to explain the observed density measurements and explored similar studies of filamentary nebulae around other central galaxies of cool-core galaxy clusters.
Abstract The Centaurus cluster is one of the most important archetypes of radio-mode active galactic nucleus (AGN) feedback, with its centra… (voir plus)l galaxy, NGC 4696, launching powerful jets that inflate X-ray cavities and regulate cooling and star formation. NGC 4696 lies within a spectacular multiphase nebula of filaments extending over tens of kiloparsecs and spanning 6 decades in temperature, from hot (10 8 K) X-ray-emitting plasma to cold molecular gas. Owing to its proximity, Hubble Space Telescope H α imaging reveals a striking S-shaped ionized-gas swirl within the black hole’s sphere of influence—the first such structure identified in a cluster core. Here we present the first JWST observations of NGC 4696 with NIRSpec, probing the inner 618 × 618 pc at 10 pc resolution. These data reveal that the ionized swirl is a rotating, multiphase circumnuclear disk (CND) physically and kinematically connected to the larger-scale filamentary network. This provides the long-sought missing link between kiloparsec-scale cooling flows and black hole accretion on 100 pc scales. Strikingly, the observed morphology and kinematics are reproduced by tailored magnetohydrodynamic simulations, in which fila
High-resolution X-ray spectroscopy with XRISM has revealed complex, non-monotonic velocity dispersion profiles in the Perseus cluster, point… (voir plus)ing to a complex interplay between at least two physical drivers of motions caused by dynamical processes within the intracluster medium (ICM). To further explore this conclusion, we perform a suite of idealized, controlled simulations targeting the relative roles of merger-induced sloshing and active galactic nucleus (AGN) feedback. Our models systematically isolate and combine these mechanisms to predict observable velocity profiles and X-ray line shapes, providing direct comparison to XRISM and Hitomi data. We find that neither sloshing nor AGN activity alone can reproduce the observed velocity dispersion profile; only their combined action matches the elevated dispersions both at the cluster core and outskirts. Power-spectrum analysis reveals distinct spatial signatures: sloshing generates large-scale coherent motions, while AGN feedback injects turbulence and broadens the velocity spectrum at small scales, especially in the core. By forward-modeling spectral line profiles, we show how these dynamics imprint unique observational signatures on X-ray emission. Our results underscore the necessity of accounting for both large-scale and small-scale drivers of gas motions in the ICM when interpreting high-resolution spectroscopic data, and provide guidance for the analysis of forthcoming XRISM observations.