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Abstract The hot plasma in galaxy clusters, the intracluster medium, is expected to be shaped by subsonic turbulent motions, which are key for heating, cooling, and transport mechanisms. The turbulent motions contribute to the nonthermal pressure, which, if not accounted for, consequently imparts a hydrostatic mass bias. Accessing information about turbulent motions is thus of major astrophysical and cosmological interest. Characteristics of turbulent motions can be indirectly accessed through surface brightness fluctuations. This study expands on our pilot investigations of surface brightness fluctuations in the Sunyaev–Zel’dovich and in X-ray data by examining, for the first time, a large sample of 60 clusters using both SPT-SZ and XMM-Newton data and spans the redshift range 0.2 < z < 1.5, thus constraining the respective pressure and density fluctuations within 0.6R₅₀₀. We deem density fluctuations to be of sufficient quality for 32 clusters, finding mild correlations between the peak of the amplitude spectra of density fluctuations and various dynamical parameters. We infer turbulent velocities from density fluctuations with an average Mach number ${\mathcal{M}}_{\text{3D}}=0.52\pm 0.14$, in agreement with numerical simulations. For clusters with inferred turbulent Mach numbers from fluctuations in both pressure, ${\mathcal{M}}_{\text{P}}$, and density, ${\mathcal{M}}_{\rho }$, we find broad agreement between ${\mathcal{M}}_{\text{P}}$and ${\mathcal{M}}_{\rho }$. Our results suggest either a bimodal or a skewed unimodal Mach number distribution, with the majority of clusters being turbulence-dominated (subsonic) while the remainder are shock-dominated (supersonic). 

Abstract We present joint South Pole Telescope and XMM-Newton observations of eight massive galaxy clusters (0.8–2 × 10¹⁵M_⊙) spanning a redshift range of 0.16–0.35. Employing a novel Sunyaev–Zel’dovich + X-ray fitting technique, we effectively constrain the thermodynamic properties of these clusters out to the virial radius. The resulting best-fit electron density, deprojected temperature, and deprojected pressure profiles are in good agreement with previous observations of massive clusters. For the majority of the cluster sample (five out of eight clusters), the entropy profiles exhibit a self-similar behavior near the virial radius. We further derive hydrostatic mass, gas mass, and gas fraction profiles for all clusters up to the virial radius. Comparing the enclosed gas fraction profiles with the universal gas fraction profile, we obtain nonthermal pressure fraction profiles for our cluster sample at  >0.5R₅₀₀, demonstrating a steeper increase betweenR₅₀₀andR₂₀₀that is consistent with the hydrodynamical simulations. Our analysis yields nonthermal pressure fraction ranges of 8%–28% (median: 15% ± 11%) atR₅₀₀and 21%–35% (median: 27% ± 12%) atR₂₀₀. Notably, weak-lensing mass measurements are available for only four clusters in our sample, and our recovered total cluster masses, after accounting for nonthermal pressure, are consistent with these measurements. 

Abstract We report the results from a study of two massive (M_500c> 6.0 × 10¹⁴M_⊙) strong-lensing clusters selected from the South Pole Telescope cluster survey for their large Einstein radius (R_E> 40″), SPT-CL J2325−4111 and SPT-CL J0049−2440. Ground-based and shallow Hubble Space Telescope (HST) imaging indicated extensive strong-lensing evidence in these fields, with giant arcs spanning 18″ and 31″, respectively, motivating further space-based imaging follow-up. Here, we present multiband HST imaging and ground-based Magellan spectroscopy of the fields, from which we compile detailed strong-lensing models. The lens models of SPT-CL J2325−4111 and SPT-CL J0049−2440 were optimized using nine and eight secure multiply imaged systems with a final image-plane rms of 0 $\stackrel{″}{.}$63 and 0 $\stackrel{″}{.}$73, respectively. From the lensing analysis, we measure a projected mass density within 500 kpc ofM(<500 kpc) = (7.30 ± 0.07) × 10¹⁴M_⊙and $M(<500\mathrm{kpc})=7.12_{-0.19}^{+0.16}\times 10^{14}$M_⊙for these two clusters, and subhalo mass ratios of 0.12 ± 0.01 and $0.21_{-0.05}^{+0.07}$, respectively. Both clusters produce a large area with high magnification (μ≥ 3) for a source atz= 9, ${\mathcal{A}}_{\left|\mu \right|\ge 3}^{\mathrm{lens}}=4.93_{-0.04}^{+0.03}$arcmin²and ${\mathcal{A}}_{\left|\mu \right|\ge 3}^{\mathrm{lens}}=3.64_{-0.10}^{+0.14}$arcmin², respectively, placing them in the top tier of strong-lensing clusters. We conclude that these clusters are spectacular sightlines for further observations that will reduce the systematic uncertainties due to cosmic variance. This paper provides the community with two additional well-calibrated cosmic telescopes, as strong as the Frontier Fields and suitable for studies of the highly magnified background Universe. 

Abstract The metallicity of galaxies, and its variation with galactocentric radius, provides key insights into the formation histories of galaxies and the physical processes driving their evolution. In this work, we analyze the radial metallicity gradients of star-forming galaxies in the EAGLE, Illustris, IllustrisTNG, and SIMBA cosmological simulations across broad mass (10^8.0M_⊙≤M_⋆ ≲ 10^12.0M_⊙) and redshift (0 ≤z≤ 8) ranges. We find that all simulations predict strong negative (i.e., radially decreasing) metallicity gradients at early cosmic times, likely due to their similar treatments of relatively smooth stellar feedback not providing sufficient mixing to quickly flatten gradients. The strongest redshift evolution occurs in galaxies with stellar masses of 10^10.0–10^11.0M_⊙, while galaxies with stellar mass < 10¹⁰M_⊙and >10¹¹M_⊙exhibit weaker redshift evolution. Our result of negative gradients at high redshift contrast with the many positive and flat gradients in the 1 < z < 4 observational literature. Atz > 6, the negative gradients observed with JWST and the Atacama Large Millimeter/submillimeter Array are flatter than those in simulations, albeit with closer agreement than at lower redshift. Overall, we suggest that these smooth stellar feedback galaxy simulations may not sufficiently mix their metal content radially, and that either stronger stellar feedback or additional subgrid turbulent metal diffusion models may be required to better reproduce observed metallicity gradients. 

Abstract We report the detection of the [Oiii] auroral line in 42 galaxies within the redshift range of 3 <z< 10. These galaxies were selected from publicly available JWST data releases, including the JADES and PRIMAL surveys, and observed using both the low-resolution PRISM/CLEAR configuration and medium-resolution gratings. The measured electron temperatures in the high-ionization regions of these galaxies range fromT_e([Oiii]) = 12,000 to 24,000 K, consistent with temperatures observed in local metal-poor galaxies and previous JWST studies. In 10 galaxies, we also detect the [Oii] auroral line, allowing us to determine electron temperatures in the low-ionization regions, which range betweenT_e([Oii]) = 10,830 and 20,000 K. The directT_e-based metallicities of our sample span from 12 + log(O/H) = 7.2 to 8.4, indicating these high-redshift galaxies are relatively metal-poor. By combining our sample with 25 galaxies from the literature, we expand the data set to a total of 67 galaxies within 3 <z< 10, effectively more than doubling the previous sample size for directT_e-based metallicity studies. This larger data set allows us to derive empirical metallicity calibration relations based exclusively on high-redshift galaxies, using six key line ratios: R3, R2, R23, Ne3O2, O32, and O3N2. Notably, we derive a novel metallicity calibration relation for the first time using high-redshiftT_e-based metallicities: $\hat{R}$= 0.18log R2 + 0.98log R3. This new calibration significantly reduces the scatter in high-redshift galaxies compared to the $\hat{R}$relation previously calibrated for low-redshift galaxies. 

We describe the 2023 release of the spectral synthesis code Cloudy. Since the previous major release, migrations of our online services motivated us to adopt git as our version control system. This change alone led us to adopt an annual release scheme, accompanied by a short release paper, the present being the inaugural. Significant changes to our atomic and molecular data have improved the accuracy of Cloudy predictions: we have upgraded our instance of the Chianti database from version 7 to 10; our H- and He-like collisional rates to improved theoretical values; our molecular data to the most recent LAMDA database, and several chemical reaction rates to their most recent UDfA and KiDA values. Finally, we describe our progress on upgrading Cloudy's capabilities to meet the requirements of the X-ray microcalorimeters aboard the upcoming XRISM and Athena missions, and outline future developments that will make Cloudy of use to the X-ray community. 

ABSTRACT We report results from deep Suzaku and mostly snapshot Chandra observations of four nearby galaxy groups: MKW4, Antlia, RXJ1159+5531, and ESO3060170. Their peak temperatures vary over 2–3 keV, making them the smallest systems with gas properties constrained to their viral radii. The average Fe abundance in the outskirts (R > 0.25R200) of their intragroup medium is $$Z_{\rm Fe}=0.309\pm 0.018\, Z_\odot$$ with χ2 = 14 for 12 degrees of freedom, which is remarkably uniform and strikingly similar to that of massive galaxy clusters, and is fully consistent with the numerical predictions from the IllustrisTNG cosmological simulation. Our results support an early-enrichment scenario among galactic systems over an order of magnitude in mass, even before their formation. When integrated out to R200, we start to see a tension between the measured Fe content in intracluster medium and what is expected from supernovae yields. We further constrain their O, Mg, Si, S, and Ni abundances. The abundance ratios of those elements relative to Fe are consistent with the predictions (if available) from IllustrisTNG. Their Type Ia supernovae fraction varies between 14 per cent and 21 per cent. A pure core-collapsed supernovae enrichment at group outskirts can be ruled out. Their cumulative iron-mass-to-light ratios within R200 are half that of the Perseus cluster, which may imply that galaxy groups do not retain all of their enriched gas due to their shallower gravitational potential wells, or that groups and clusters may have different star formation histories.