The elements in the Universe are synthesized primarily in stars and supernovae, where nuclear fusion favours the production of even-Z elements. In contrast, odd-Z elements are less abundant and their yields are highly dependent on detailed stellar physics, making theoretical predictions of their cosmic abundance uncertain. In particular, the origin of odd-Z elements such as phosphorus (P), chlorine (Cl) and potassium (K), which are important for planet formation and life, is poorly understood. While the abundances of these elements in Milky Way stars are close to solar values, supernova explosion models systematically underestimate their production by up to an order of magnitude, indicating that key mechanisms for odd-Z nucleosynthesis are currently missing from theoretical models. Here we report the observation of P, Cl and K in the Cassiopeia A supernova remnant using high-resolution X-ray spectroscopy with X-Ray Imaging and Spectroscopy Mission data, with the detection of K at above the 6 sigma level being the most significant finding. Supernova explosion models of normal massive stars cannot explain the element abundance pattern, especially the high abundances of Cl and K, while models that include stellar rotation, binary interactions or shell mergers agree closely with the observations. Our observations suggest that such stellar activity plays an important role in supplying these elements to the Universe.

AC 114 is a historically significant galaxy cluster, being one of the first strong lensing clusters detected from the ground in the early 1990s, prior to the launch of the Hubble Space Telescope (HST). Despite this early prominence, no detailed lensing analyses were carried out for more than 15 years. We studied this cluster using James Webb Space Telescope (JWST) imaging obtained as part of the Strong LensIng and Cluster Evolution (SLICE) programme, complemented by archival HST and X-ray observations. JWST data reveal ten new multiply imaged systems and enabled the identification of conjugate substructures in several of the 16 systems, significantly increasing the number of strong lensing constraints. Using these data, we constructed a parametric mass model with LENSTOOL and extended it by explicitly incorporating the Chandra data in a combined strong lensing+X-ray fit, following the methodology recently introduced by us. Our best-fit model reproduces the multiple images with an RMS of 0.4″ while simultaneously matching the X-ray data. The dark matter distribution is unimodal and centred on the brightest cluster galaxy, with a large core radius of 83 ± 5 kpc, consistent with values reported in other strong lensing clusters. The strong lensing constraints require the inclusion of an external shear component whose position angle points unambiguously towards a nearby (∼1 Mpc), well-defined mass concentration at the same redshift in the north-west, for which we propose the name AC 114b. The spatial coverage of the XMM-Newton data encompasses the whole structure, allowing us to probe the X-ray properties of the companion cluster and the thermodynamics of AC 114. This provided further evidence of a major merger, in line with previous signatures seen in Chandra, radio, and optical spectroscopic data. Our results shed new light on the merging scenario, revealing a major merger caught in a late post-collisional phase, where AC 114 is the dominant system and AC 114 b has likely been stripped of its hot gas. Our analysis highlights the power of combining strong lensing constraints with X-ray data to disentangle the dark matter and gas components and to investigate the dynamical processes driving cluster mergers. Our lens model and associated products are available for download at the Strong Lensing Cluster Atlas Data Base, which is hosted at Laboratoire d’Astrophysique de Marseille.

Galaxies with intense star formation often host multiphase, galaxy-scale winds powered by supernovae and fast stellar winds. These are strong enough to disrupt the star-forming interstellar medium, and they chemically enrich the surrounding circumgalactic medium. However, their launching mechanism remains unknown. Here we show that thermal gas pressure is sufficient to drive the multiphase wind in the prototypical starburst galaxy M82. Using a high energy-resolution (ΔE = 4.5 eV) XRISM Resolve spectrum, including detections of FeXXV 6.7 keV, ArXVII 3.1 keV, and SXVI 2.6 keV, we measure the temperature (T = 2.3^+0.5_-0.2× 10^7 K) and mass (M ≈ 6 ± 2 × 10^5 M_⊙) of the hot gas in the starburst and provide the first direct measurement of its line-of-sight velocity dispersion (σ= 595^+464_-128 km s^-1). These values are consistent with a freely-expanding wind exceeding the galactic escape velocity. The size of the FeXXV-emitting region suggests a hot gas outflow rate of Ṁ≈ 4 M_⊙ yr^-1, carrying a total energy of Ė≈ 2 × 10^42 erg s^-1. This is sufficient to drive the molecular, atomic, and ionized outflows while transporting up to ≈ 2 M_⊙ yr^-1 of hot gas to the intergalactic medium. The estimated supernova rate implies that ≈ 60

We present a cosmological analysis of the X-ray-selected galaxy cluster sample from the XXL survey, employing a simulation-based inference (SBI) framework to jointly constrain cosmological parameters and X-ray scaling relations through forward modeling of cluster counts, X-ray observables, and weak-lensing measurements. Our analysis combines X-ray data from the XMM-XXL survey with shear measurements from the three-year shape catalog of the Hyper Suprime-Cam Subaru Strategic Program. The analysis focuses on the XXL C1 sample, comprising 171 clusters for abundance modeling, a subset of 86 clusters located within the XXL-N region for lensing-based mass calibration, and 162 clusters with X-ray temperature and luminosity measurements used to constrain scaling relations. Using the density-estimation likelihood-free inference (DELFI) algorithm, we construct a forward model with 12 parameters that incorporates the XXL selection function and cluster population modeling and accounts for key systematic effects including cluster miscentering, photometric redshift bias, and mass-dependent weak-lensing bias. Our SBI analysis yields a constraint on the cosmological parameter S_8 ≡ σ_8 (Ω_m/0.3)^0.5 = 0.867 ± 0.063, with an additional 3

The supermassive binary system, eta Carinae, is experiencing enormous wind-driven mass loss at a rate unparalleled in the rest of the Galaxy. Their wind-wind collision (WWC) continuously produces shock heated, X-ray-emitting plasmas. The XRISM X-ray observatory observed the system in 2023 and 2024 when the X-ray emission began to increase toward periastron passage in 2025. This paper reports unprecedentedly high-resolution X-ray spectra in the Fe K alpha band between 6.2 and 7.1 keV, obtained with the Resolve X-ray microcalorimeter. The hydrogen-like (Ly alpha) and helium-like (He alpha) lines reveal three velocity components. Two of them are broadened with maximum velocities of 2000-3000 km s-1, likely originating from the postshock companion wind. The other is relatively narrow, with a Gaussian broadening of only similar to 290 km s-1 in 1 sigma, which may originate from the postshock companion wind at the WWC stagnation point or penetrating the primary wind. The Fe fluorescent lines exhibit a moderate blueshift and broadening with velocities at 100-200 km s-1, consistent with the primary wind's velocity field. The spectra also confirm a Compton shoulder of the He alpha line complex for the first time. Both fluorescing and scattering spectral profiles indicate that the binary system is seen from the companion side during these observations. The flux ratio of the Compton-scattering emission to the fluorescent line suggests substantial hydrogen depletion of the primary wind, expected from CNO-cycled hydrogen nuclear fusion gas.

Under the standard model of hierarchical structure formation, the overall geometry of galaxy clusters is better described by a triaxial ellipse than by a sphere. As a result, the application of spherically symmetric models can result in significant biases, with masses derived from weak-lensing observations being particularly sensitive. These biases can be mitigated by fitting a triaxial model, but this requires deep multi-probe data along with a set of physically motivated models to describe them. We present a multi-probe triaxial analysis method based on the data available for galaxy clusters in the Cluster Heritage project with XMM-Newton - Mass Assembly and Thermodynamics at Endpoint of structure formation (CHEX-MATE), which includes X-ray data from XMM-Newton, Sunyaev-Zel'dovich effect maps from Planck and ACT, and weak-lensing data from Subaru. This work builds upon our previous development of a gas-only X-ray and Sunyaev-Zel'dovich triaxial fitting formalism in Paper I. After verifying our approach using mock observations of model clusters with known properties, we applied it to the CHEX-MATE galaxy cluster PSZ2 G313.33+61.13 (Abell 1689). We found that the cluster is elongated along the line of sight relative to the plane of sky by a factor of & Rscr;(LP) = 1.20 +/- 0.04. As a result, the weak-lensing mass obtained from our triaxial fit, M-200c = (13.88(-1.43)(+1.73)) & times; 10(14)M(circle dot ) , is significantly lower than the value of (17.77(-1.75)(+2.00))& times;10(14)M(circle dot )obtained from a spherically symmetric fit that otherwise employed the same method. Our triaxial fit finds a concentration ofc(200c)=8.66(-1.70)(+2.08), consistent with the spherically symmetric value of 9.99+2.26-1.78, which suggests that the unexpectedly high concentration in Abell 1689 is not due to triaxiality and orientation. We also measured the nonthermal pressure fraction at radii between 0.18-1.37 Mpc and found a minimum of approximately 20% at intermediate radii, increasing to near 30% at the smallest and largest radii, and with a typical measurement precision of +/- 5%.

We present high-resolution X-ray spectroscopy of the merging galaxy cluster A3667 with XRISM/Resolve. Two observations, targeting the cluster X-ray core and the prototypical cold front, were performed with exposures of 105 and 276 ks, respectively. We find that the gas in the core is blueshifted by v(z) similar to -200 km s(-1) relative to the brightest cluster galaxy, while the low-entropy gas inside the cold front is redshifted by v(z) similar to 200 km s(-1). As one moves further off-center across the front, the line-of-sight (LoS) velocity changes significantly, by Delta v(z)=535-154+167 km s(-1), back to the value similar to that in the core. There are no significant LoS velocity gradients perpendicular to the cluster symmetry axis. These features suggest that the gas forming the cold front is flowing in the plane oriented along the LoS, supporting an offset merger scenario in which the main cluster has passed in front of the subcluster and induced rotation of the core gas in the plane perpendicular to the sky. The region just inside the front exhibits the largest LoS velocity dispersion seen across two pointings, sigma(z) similar to 420 km s(-1), which can be interpreted as a developing turbulence or a projection of the LoS velocity shear within the front. The large LoS velocity jump across the cold front, combined with the lack of Kelvin-Helmholtz instability on the surface of the front, suggests some mechanism to suppress it. For example, a magnetic field with B > 5 mu G is required if the cold front is stabilized by magnetic draping.

The intracluster medium (ICM) is rich in chemical elements, produced by core-collapse (SNIcc) and Type Ia supernovae (SNIa) over the last $\sim$12 Gyr. Whereas cluster outskirts are uniformly enriched with Fe at $\sim$0.3 solar - strongly suggesting that the gas had been pre-enriched during or before the assembly of galaxies into clusters, the Fe abundance is known to centrally increase in the core of relaxed clusters. The origin of these central Fe peaks however, as well as the apparent presence of mysterious drops previously reported in the very centre of a number of systems, remain to be clarified. In this paper, we address these two questions by measuring the spatial distribution of Fe and its relative Si/Fe, S/Fe, Ar/Fe, Ca/Fe, Cr/Fe, Mn/Fe, and Ni/Fe ratios in the X-ray bright, nearby Perseus cluster. We take advantage of the unprecedented spectral resolution ($\sim$5 eV) offered by the Resolve microcalorimeter on board XRISM, which observed four distinct pointings of Perseus out to $\sim$250 kpc ($\sim$0.2$r_{500}$) during its Performance Verification phase. Although the presence of an X-ray bright AGN challenges a precise quantification of absolute abundances in the very core, our baseline analysis rules out a strong drop with $>$2$σ$ confidence, at variance with previous CCD measurements. In addition, we find a remarkable spatial uniformity of X/Fe ratios, supporting the idea of negligible late SNIa enrichment from the brightest cluster galaxy NGC 1275. We also compare the overall chemical composition of the Perseus ICM with SNcc and SNIa nucleosynthesis yield models, finding that the co-existence of two separate SNIa enrichment channels is not needed to reproduce the ICM ratios satisfactorily.

AC 114 is a historically significant galaxy cluster, being one of the first strong lensing clusters detected from the ground in the early 1990s, prior to the launch of the Hubble Space Telescope (HST). Despite this early prominence, no detailed lensing analyses were carried out for more than 15 years. We studied this cluster using James Webb Space Telescope (JWST) imaging obtained as part of the Strong LensIng and Cluster Evolution (SLICE) programme, complemented by archival HST and X-ray observations. JWST data reveal ten new multiply imaged systems and enabled the identification of conjugate substructures in several of the 16 systems, significantly increasing the number of strong lensing constraints. Using these data, we constructed a parametric mass model with LENSTOOL and extended it by explicitly incorporating the Chandra data in a combined strong lensing+X-ray fit, following the methodology recently introduced by us. Our best-fit model reproduces the multiple images with an RMS of 0.4 '' while simultaneously matching the X-ray data. The dark matter distribution is unimodal and centred on the brightest cluster galaxy, with a large core radius of 83 +/- 5 kpc, consistent with values reported in other strong lensing clusters. The strong lensing constraints require the inclusion of an external shear component whose position angle points unambiguously towards a nearby (similar to 1 Mpc), well-defined mass concentration at the same redshift in the north-west, for which we propose the name AC 114b. The spatial coverage of the XMM-Newton data encompasses the whole structure, allowing us to probe the X-ray properties of the companion cluster and the thermodynamics of AC 114. This provided further evidence of a major merger, in line with previous signatures seen in Chandra, radio, and optical spectroscopic data. Our results shed new light on the merging scenario, revealing a major merger caught in a late post-collisional phase, where AC 114 is the dominant system and AC 114 b has likely been stripped of its hot gas. Our analysis highlights the power of combining strong lensing constraints with X-ray data to disentangle the dark matter and gas components and to investigate the dynamical processes driving cluster mergers. Our lens model and associated products are available for download at the Strong Lensing Cluster Atlas Data Base, which is hosted at Laboratoire d'Astrophysique de Marseille.

The Cluster HEritage project with XMM-Newton - Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE) is a programme to study a minimally biased sample of 118 galaxy clusters detected by Planck through the Sunyaev-Zeldovich effect. Accurate and precise mass measurements are required to exploit CHEX-MATE as an astrophysical laboratory and a calibration sample for cosmological probes in the era of large surveys. We measured masses based on the galaxy dynamics, which are highly complementary to weak-lensing or X-ray estimates. We analysed the sample with a uniform pipeline that is stable both for poorly sampled or rich clusters -using spectroscopic redshifts from public (NED, SDSS, and DESI) or private archives and dedicated observational programmes. We modelled the halo mass density and the anisotropy profile. Membership is confirmed with a cleaning procedure in phase space. We derived masses from measured velocity dispersions under the assumed model. We measured dynamical masses for 101 CHEX-MATE clusters with at least ten confirmed members within the virial radius r200c. Estimated redshifts and velocity dispersions agree with literature values when available. Validation with weak-lensing masses shows agreement within 8 +/- 16 (stat.) +/- 5 (sys.)%, and confirms dynamical masses as an unbiased proxy. Comparison with Planck masses shows them to be biased low by 34 +/- 3 (stat.) +/- 5 (sys.)%. A follow-up spectroscopic campaign is underway to cover the full CHEX-MATE sample.

The XRISM Resolve microcalorimeter array measured the velocities of hot intracluster gas at two positions in the Coma galaxy cluster: 3 ′ × 3 ′ squares at the center and at 6 ′ (170 kpc) to the south. We find the line-of-sight velocity dispersions in those regions to be σ z = 208 ± 12 km s −1 and 202 ± 24 km s −1 , respectively. The central value corresponds to a 3D Mach number of M = 0.24 ± 0.015 and a ratio of the kinetic pressure of small-scale motions to thermal pressure in the intracluster plasma of only 3.1% ± 0.4%, at the lower end of predictions from cosmological simulations for merging clusters like Coma, and similar to that observed in the cool core of the relaxed cluster A2029. Meanwhile, the gas in both regions exhibits high line-of-sight velocity differences from the mean velocity of the cluster galaxies, Δ v z = 450 ± 15 km s −1 and 730 ± 30 km s −1 , respectively. A small contribution from an additional gas velocity component, consistent with the cluster optical mean, is detected along a sight line near the cluster center. The combination of the observed velocity dispersions and bulk velocities is not described by a Kolmogorov velocity power spectrum of steady-state turbulence; instead, the data imply a much steeper effective slope (i.e., relatively more power at larger linear scales). This may indicate either a very large dissipation scale, resulting in the suppression of small-scale motions, or a transient dynamic state of the cluster, where large-scale gas flows generated by an ongoing merger have not yet cascaded down to small scales.

W49B is a unique Galactic supernova remnant with centrally peaked, “bar”-like ejecta distribution, which was once considered evidence for a hypernova origin that resulted in a bipolar ejection of the stellar core. However, chemical abundance measurements contradict this interpretation. Closely connected to the morphology of the ejecta is its velocity distribution, which provides critical details for understanding the explosion mechanism. We report the first ever observational constraint on the kinematics of the ejecta in W49B using the Resolve microcalorimeter spectrometer on the X-ray Imaging and Spectroscopy Mission (XRISM). Using XRISM/Resolve, we measured the line-of-sight velocity traced by the Fe He α emission, which is the brightest feature in the Resolve spectrum, to vary by ±300 km s ^−1 with a smooth east-to-west gradient of a few tens of kilometers per second per parsec along the major axis. Similar trends in the line-of-sight velocity structure were found for other Fe-group elements Cr and Mn, traced by the He α emission, and also for intermediate-mass elements Si, S, Ar, and Ca, traced by the Ly α emission. The discovery of the east–west gradient in the line-of-sight velocity, together with the absence of a twin-peaked line profile or enhanced broadening in the central region, clearly rejects the equatorially expanding disk model. In contrast, the observed velocity structure suggests bipolar flows reminiscent of a bipolar explosion scenario. An alternative scenario would be a collimation of the ejecta by an elongated cavity sculpted by bipolar stellar winds.

We present results from XRISM/Resolve observations of the core of the galaxy cluster Abell 2319, focusing on its kinematic properties. The intracluster medium (ICM) exhibits temperatures of approximately 8 keV across the core, with a prominent cold front and a high-temperature region (-11 keV) in the north-west. The average gas velocity in the 3' x 4' region around the brightest cluster galaxy (BCG) covered by two Resolve pointings is consistent with that of the BCG to within 40 km s(-1) and we found modest average velocity dispersion of 230-250 km s(-1) . On the other hand, spatially resolved spectroscopy reveals interesting variations. A blueshift of up to similar to 230 km s(-1) is observed around the east edge of the cold front, where the gas with the lowest specific entropy is found. The region further south inside the cold front shows only a small velocity difference from the BCG; however, its velocity dispersion is enhanced to -400 km s(-1), implying the development of turbulence. These characteristics indicate that we are observing sloshing motion with some inclination angle following BCG and that gas phases with different specific entropy participate in sloshing with their own velocities, as expected from simulations. No significant evidence for a high-redshift ICM component associated with the subcluster Abell 2319B was found in the region covered by the current Resolve pointings. These results highlight the importance of sloshing and turbulence in shaping the internal structure of Abell 2319. Further deep observations are necessary to better understand the mixing and turbulent processes within the cluster.

Context. Accurate X-ray spectroscopic measurements are fundamental for deriving basic physical parameters of the most abundant baryon components in the Universe. The plethora of X-ray observatories currently operational enables a panchromatic view of the high-energy emission of celestial sources. However, uncertainties in the energy-dependent calibration of the instrument transfer functions (e.g. the effective area, energy redistribution, or gain) can limit - and historically, did limit - the accuracy of X-ray spectroscopic measurements. Aims. We revised the status of the cross-calibration among the scientific payload on board four operation missions: Chandra, NuSTAR, XMM-Newton, and the recently launched XRISM. XRISM carries the micro-calorimeter Resolve, which yields the best energy resolution at energies >= 2 keV. For this purpose, we used the data from a 10-day-long observational campaign targeting the nearby active galactic nucleus NGC 3783, carried out in July 2024. Methods. We present a novel model-independent method for assessing the cross-calibration status that is based on a multi-node spline of the spectra with the highest-resolving power (XRISM/Resolve in our campaign). We also estimated the impact of the intrinsic variability of NGC 3783 on the cross-calibration status due to the different time coverages of participating observatories and performed an empirical reassessment of the Resolve throughput at low energies. Results. Based on this analysis, we derived a set of energy-dependent correction factors of the observed responses, enabling a statistically robust analysis of the whole spectral dataset. They will be employed in subsequent papers describing the astrophysical results of the campaign.

Context. The baryon fraction of galaxy clusters, expressed as the ratio between the mass in baryons (including both stars and cold or hot gas) and the total mass, is a powerful tool to provide information on the cosmological parameters, while the hot-gas fraction provides indications on the physics of the intracluster plasma and its interplay with the processes that drive galaxy formation. Aims. Using cosmological hydrodynamical simulations of about 300 simulated massive galaxy clusters with a median mass M-500 approximate to 7 x 10(14) M-circle dot at z = 0, we model the relations between total mass and either baryon fraction or the hot gas fractions at overdensities Delta = 2500, 500, and 200 with respect to the cosmic critical density, and their evolution from z similar to 0 to z similar to 1.3. Methods. We utilized the simulated galaxy clusters from the Three Hundred project, which include star formation and feedback from both supernovae and active galactic nuclei. We fit the simulation results for such scaling relations against three analytic forms (linear, quadratic, and logarithmic in a logarithmic plane) and three forms for the redshift dependence, and we considered as a variable both the inverse of the cosmic scale factor, (1 + z), and the Hubble expansion rate, E(z). Results. We show that power-law dependencies on cluster mass poorly describe the investigated relations. A power law fails to simultaneously capture the flattening of the total baryon and gas fractions at high masses, their drop at low masses, and the transition between these two regimes. The other two functional forms provide a more accurate description of the curvature in mass scaling. The fractions measured within smaller radii exhibit a stronger evolution than those measured within larger radii. Conclusions. From the analysis of these simulations, we evince that as long as we include systems in the mass range herein investigated, the baryon or gas fraction can be accurately related to the total mass through either a parabola or a logarithm in the logarithmic plane. The trends are common to all modern hydro simulations, although the amplitude of the drop at low masses might differ. Being able to observationally determine the gas fraction in groups will thus provide constraints on the baryonic physics.

We present XRISM Resolve observations of the core of the hot, relaxed galaxy cluster Abell 2029 (A2029). We find that the line-of-sight bulk velocity of the intracluster medium (ICM) within the central 180 kpc is at rest with respect to the brightest cluster galaxy, with a 3 σ upper limit of ∣ v bulk ∣ < 100 km s −1 . We robustly measure the field-integrated ICM velocity dispersion to be σ v = 169 ± 10 km s −1 , obtaining similar results for both single-temperature and two-temperature plasma models to account for the cluster cool core. This result, if ascribed to isotropic turbulence, implies a subsonic ICM with Mach number M 3 D ≈ 0.22 and a nonthermal pressure fraction of 2.6 ± 0.3%. The turbulent velocity is similar to what was measured in the core of the Perseus cluster by Hitomi, but here in a more massive cluster with an ICM temperature of 7 keV, the limit on the nonthermal pressure fraction is even more stringent. Our result is consistent with expectations from simulations of relaxed clusters, but it is on the low end of the predicted distribution, indicating that A2029 is an exceptionally relaxed cluster with no significant impacts from either a recent minor merger or active galactic nucleus activity.

Context. Cluster cosmology can benefit from combining multi-wavelength studies. In turn, these studies benefit from a characterisation of the correlation coefficients among different mass-observable relations. Aims. In this work, we aim to provide information on the scatter, skewness, and covariance of various mass-observable relations in galaxy clusters in cosmological hydrodynamic simulations. This information will help future analyses improve the general approach to accretion histories and projection effects, as well as to model mass-observable relations for cosmology studies. Methods. We identified galaxy clusters in Magneticum Box2b simulations with masses of M-200c > 10(14) M-circle dot at redshifts of z = 0.24 and z = 0.90. Our analysis included Euclid-derived properties such as richness, stellar mass, lensing mass, and concentration. Additionally, we investigated complementary multi-wavelength data, including X-ray luminosity, integrated Compton-y parameter, gas mass, and temperature. We then examined the impact of projection effects on mass-observable residuals and correlations. Results. We find that at intermediate redshift (z = 0.24), projection effects have the greatest impact of lensing concentration, richness, and gas mass in terms of the scatter and skewness of the log-residuals of scaling relations. The contribution of projection effects can be significant enough to boost a spurious hot- versus cold-baryon correlations and consequently hide underlying correlations due to halo accretion histories. At high redshift (z = 0.9), the richness has a much lower scatter (of log-residuals), while the quantity that is most impacted by projection effects is the lensing mass. The lensing concentration reconstruction, in particular, is affected by deviations of the reduced-shear profile shape from that derived using a Navarro-Frenk-White (NFW) profile; the amount of interlopers in the line of sight, on the other hand, is not as important.

We analysed the kinematical properties of the CHEX-MATE galaxy cluster sample. Our study is based on the radial velocities retrieved from the SDSS DR18, DESI, and NED spectroscopic databases and new data obtained with the 10.4 m GTC and ESO-NTT telescopes. We derived cluster mass profiles for 75 clusters using the MG-MAMPOSST procedure, which recovers the gravitational potential and the anisotropy profiles from line-of-sight velocities and projected positions of galaxy members. The standard Navarro-Frenk-White (NFW) model and the Burkert model, with flatter cores than the NFW, both adequately fit the kinematic data, with only a marginal statistical preference for one model over the other. An estimation of the mass bias (1-B1) = M500SZ/M500M ( 1 - B 1 ) = M 500 SZ / M 500 M $ (1-B_1) = M<<^>>{\mathrm{SZ}}_{500}/M<<^>>{M}_{500} $ was performed via a comparison with Sunyaev-Zel'dovich-X-ray-calibrated mass estimates, resulting in a value of 0.54 +/- 0.11 when four evidently disturbed clusters are removed from the sample. We assessed the dynamical state of the clusters by inferring the Anderson-Darling coefficient (A2) and the fraction of galaxies in substructures (fsub). Except for a few cases, we find relatively low values for A2, which suggests that CHEX-MATE clusters are not too far from relaxation. Moreover, no significant trends emerge between A2 and fsub, nor between the log-masses estimated by MG-MAMPOSST and those based on the Sunyaev-Zel'dovich effect calibrated through X-rays measurements. We studied the concentration-mass relation for the sample; despite the large scatter, we observe signs of an increasing trend for high-mass clusters, in agreement with recent theoretical expectations. Finally, our analysis of the radial anisotropy profiles of member galaxies - stacked in five bins of mass and redshift - reveals that orbits tend to be isotropic at the centre and more radial towards the edge, as found in previous studies. A slight trend of increasing radial orbits at r200 is observed in clusters with larger velocity dispersions.

We stack 3.75 Megaseconds of early XRISM Resolve observations of ten galaxy clusters to search for unidentified spectral lines in the E= 2.5-15 keV band (rest frame), including the E=3.5 keV line reported in earlier, low spectral resolution studies of cluster samples. Such an emission line may originate from the decay of the sterile neutrino, a warm dark matter (DM) candidate. No unidentified lines are detected in our stacked cluster spectrum, with the 3σ upper limit on the m_ s∼ 7.1 keV DM particle decay rate (which corresponds to a E=3.55 keV emission line) of Γ∼ 1.0 × 10^-27 s^-1. This upper limit is 3-4 times lower than the one derived by Hitomi Collaboration et al. (2017) from the Perseus observation, but still 5 times higher than the XMM-Newton detection reported by Bulbul et al. (2014) in the stacked cluster sample. XRISM Resolve, with its high spectral resolution but a small field of view, may reach the sensitivity needed to test the XMM-Newton cluster sample detection by combining several years worth of future cluster observations.

This study presents highly precise measurements of the cross-correlation between volume-limited galaxy samples from the DESI Legacy Survey catalog and X-ray-selected galaxy clusters from eROSITA, which allows for a detailed analysis across redshift and color. Two key findings emerge. First, the cluster-galaxy cross-correlation, when split into quiescent and star-forming galaxies, contains significant information about the infall, feedback, and quenching processes of blue-cloud galaxies in massive environments. These results align well with existing galaxy evolution models for higher stellar masses (log(10)(M*[M-circle dot]) > 10.75), although the red fraction may be slightly underestimated in the intermediate mass range (10.25 < log(10)(M*[M-circle dot]) < 10.75). Second, the integral of the cross-correlation within 500 kpc enables a model-independent measurement of the red sequence and its scatter in clusters, providing a robust alternative to existing red-sequence calibration methods, without requiring spectroscopic redshifts or classifications of galaxies. Similar analyses on upcoming photometric surveys like Euclid and Rubin/LSST and spectroscopic samples such as 4MOST and DESI should lead to a significant increase in the signal-to-noise ratio, particularly at small separations.