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.

The X-ray source around supermassive black holes in active galactic nuclei (AGN) has been dubbed the corona by analogy to the solar (and stellar) corona. Both stellar and AGN coronae are orders of magnitude hotter than their counterpart optical source; the stellar photosphere and accretion disk respectively. Both coronae vary on short time scales down to seconds. The coronal activity in the Sun is well imaged and its activity has been shown to be driven by magnetic energy converted into heat through the process of magnetic reconnection. While it has been theorized that AGN corona are also magnetically driven, the driving mechanism of AGN coronal activity has not been directly observed. A smoking gun of magnetic reconnection is when a coronal flare’s temporal evolution in hard and soft X-rays follows the Neupert Effect. These flares result in both a solar coronal mass ejection, and energetic particles streaming down along magnetic field lines to the photosphere. Here, we report the detection of the Neupert Effect in an AGN corona, providing the first direct evidence for magnetic reconnection in AGN. Our measurements indicate a magnetic field loop height of up to 30 gravitational radii, and a distance of about 400 gravitational radii between the corona and the UV emitting accretion disk. The present findings thus enable the application of solar coronal physics to the less accessible AGN corona.

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

The X-ray source in AGN is commonly referred to as the corona by analogy to stellar coronae. The similarities between the two suggest that the heating mechanism of AGN coronae is magnetic reconnection – as in cool stars – but this has not yet been directly observed. This work presents the first observational evidence for a magnetic reconnection flare in an AGN corona. We report on a flare in NGC 3783, which was observed with XRISM/Xtend and XMM-Newton/EPIC-PN exhibiting distinct temporal evolution in soft (<2.0keV) and hard (>2.0keV) X-rays. An Ultra-Fast Outflow (UFO) was detected during the event. The flare features the Neupert effect – a temporal signature of the hard light curve correlating with the time derivative of the soft light curve, which shows that the flare is powered by magnetic reconnection, The Neupert effect is widely observed in the Sun, with Coronal Mass Ejections (CMEs) playing a role analogous to the UFO. We derive an upper limit of 30 R_g on the height of the magnetic loop from which the flare originates. Using the UFO's measured properties to characterize the magnetic field, we obtain B > 1.3 × 10^4G for the field annihilated during the flare from total energy considerations, and B ≈ 500G for the momentary magnetic field during reconnection from a dynamical consideration.

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.

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.

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.

Context. Ionized outflows in active galactic nuclei are thought to influence the evolution of their host galaxies and supermassive black holes. Taking distance into account is important when deriving the kinetic power of the outflows as a cosmic feedback channel. However, the distance between the outflows and the central engine is poorly constrained. The density of the outflows is an essential parameter for estimating this distance. NGC 5548 exhibits a variety of spectroscopic features in its archival spectra, which can be used for density analysis.Aims. We used the variability in the absorption lines from the archival spectra to obtain a density constraint and then estimate the distance to the outflows.Methods. We used the archival observations of NGC 5548 taken with Chandra in January 2002 to search for variations in the absorption lines.Results. We find that the Mg XII Ly alpha and the O VIII Ly beta absorption lines vary significantly on the similar to 144 ks and similar to 162 ks timescales during the different observation periods. Based on the variability timescales and the physical properties of the variable components that dominated these two absorption lines, we derived a lower limit on the density of the variable warm absorber components in the range similar to 7.2-9.0 x 10(11) m(-3), and an upper limit on their distance from the central source in the range similar to 0.2-0.5 pc.

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.

We present our study of the XRISM observation of the Seyfert-1 galaxy NGC 3783. XRISM's Resolve microcalorimeter has enabled, for the first time, a detailed characterization of the highly ionized outflows in this active galactic nucleus. Our analysis constrains their outflow and turbulent velocities, along with their ionization parameter (ξ) and column density (N_ H). The high-resolution Resolve spectrum reveals a distinct series of Fe absorption lines between 6.4 and 7.8 keV, ranging from Fe XVIII to Fe XXVI. At lower energies, absorption features from Si, S, and Ar are also detected. Our spectroscopy and photoionization modeling of the time-averaged Resolve spectrum uncovers six outflow components, five of which exhibit relatively narrow absorption lines with outflow velocities ranging from 560 to 1170 km/s. In addition, a broad absorption feature is detected, which is consistent with Fe XXVI outflowing at 14,300 km/s (0.05 c). The kinetic luminosity of this component is 0.8-3

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.

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.

Black hole accretion in active galactic nuclei (AGN) is coupled to the evolution of their host galaxies. Outflowing winds in AGN can play an important role in this evolution through the resulting feedback mechanism. Multi-wavelength spectroscopy is key for probing the intertwined physics of inflows and outflows in AGN. However, with the current spectrometers, crucial properties of the ionized outflows are poorly understood, such as their coupling to accretion rate, their launching mechanism, and their kinetic power. We discuss the need for simultaneous X-ray and UV high-resolution spectroscopy for tackling outstanding questions on these outflows in AGN. The instrumental requirements for achieving the scientific objectives are addressed. We demonstrate that these requirements would be facilitated by the proposed Arcus Probe mission concept. The multi-wavelength spectroscopy and timing by Arcus would enable us to establish the kinematics and ionization structure of the entire ionized outflow, extending from the vicinity of the accretion disk to the outskirts of the host galaxy. Arcus would provide key diagnostics on the origin, driving mechanism, and energetics of the outflows, which are useful benchmarks for testing various theoretical models of outflows and understanding their impact in AGN. (c) 2024 Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI:10.1117/1.JATIS.11.1.011008]

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.

We reanalyse the Chandra/HETGS observations of NGC 3783 from the campaign in the year 2001 and identify significant spectral variations in the Fe unresolved transition array (UTA) over timescales of weeks to months. These changes correlate with a 1.4- to two-fold increase in the ionising continuum and exceed 10 sigma significance. The variations primarily originate from a low-ionisation state (log xi = 1.65) component of the warm absorber. Time-dependent photoionisation modelling confirmed the sensitivity of this low-ionisation component to continuum variations within the Fe UTA band. Local fitting indicated a lower density limit of > 10(12.3) m(-3) at a 3 sigma statistical uncertainty, with the component located within 0.27 pc. Our findings suggest that this low-ionisation component is a potential failed wind candidate.

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.

The X-Ray Imaging and Spectroscopy Mission (XRISM) is a joint mission between the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) in collaboration with the European Space Agency (ESA). In addition to the three space agencies, universities and research institutes from Japan, North America, and Europe have joined to contribute to developing satellite and onboard instruments, data-processing software, and the scientific observation program. XRISM is the successor to the ASTRO-H (Hitomi) mission, which ended prematurely in 2016. Its primary science goal is to examine astrophysical problems with precise, high-resolution X-ray spectroscopy. XRISM promises to discover new horizons in X-ray astronomy. It carries a 6 x 6 pixelized X-ray microcalorimeter on the focal plane of an X-ray mirror assembly (Resolve) and a co-aligned X-ray CCD camera (Xtend) that covers the same energy band over a large field of view. XRISM utilizes the Hitomi heritage, but all designs were reviewed. The attitude and orbit control system was improved in hardware and software. The spacecraft was launched from the JAXA Tanegashima Space Center on 2023 September 6 (UTC). During the in-orbit commissioning phase, the onboard components were activated. Although the gate valve protecting the Resolve sensor with a thin beryllium X-ray entrance window was not yet opened, scientific observation started in 2024 February with the planned performance verification observation program. The nominal observation program commenced with the following guest observation program beginning in 2024 September.

We stack 3.75 Ms of early XRISM Resolve observations of 10 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 3 σ upper limit on the m s ∼ 7.1 keV DM particle decay rate (which corresponds to an 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 from the Perseus observation but still 5 times higher than the XMM-Newton detection reported by E. Bulbul et al. in the stacked cluster sample. XRISM Resolve, with its high spectral resolution but 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.

The Athena mission entered a redefinition phase in July 2022, driven by the imperative to reduce the mission cost at completion for the European Space Agency below an acceptable target, while maintaining the flagship nature of its science return. This notably called for a complete redesign of the X-ray Integral Field Unit (X-IFU) cryogenic architecture towards a simpler active cooling chain. Passive cooling via successive radiative panels at spacecraft level is now used to provide a 50 K thermal environment to an X-IFU owned cryostat. 4.5 K cooling is achieved via a single remote active cryocooler unit, while a multi-stage Adiabatic Demagnetization Refrigerator ensures heat lift down to the 50 mK required by the detectors. Amidst these changes, the core concept of the readout chain remains robust, employing Transition Edge Sensor microcalorimeters and a SQUID-based Time-Division Multiplexing scheme. Noteworthy is the introduction of a slower pixel. This enables an increase in the multiplexing factor (from 34 to 48) without compromising the instrument energy resolution, hence keeping significant system margins to the new 4 eV resolution requirement. This allows reducing the number of channels by more than a factor two, and thus the resource demands on the system, while keeping a 4' field of view (compared to 5' before). In this article, we will give an overview of this new architecture, before detailing its anticipated performances. Finally, we will present the new X-IFU schedule, with its short term focus on demonstration activities towards a mission adoption in early 2027.

In this paper we introduce the clus model, which has been newly implemented in the X-ray spectral fitting software package SPEX. Based on 3D radial profiles of the gas density, temperature, and metal abundance as well as the turbulent, inflow, and outflow velocities, the clus model creates spectra for a chosen projected region on the sky. Additionally, it can also take into account the resonant scattering. We show a few applications of the clus model on simulated spectra of the massive elliptical galaxy NGC 4636; galaxy clusters A383, A2029, A1795, and A262; and the Perseus cluster. We quantify the effect of projection as well as the resonant scattering on inferred profiles of the iron abundance and temperature, assuming a resolution similar to Chandra ACIS-S and XRISM Resolve. Our results show that depending on the mass of the object as well as the projected distance from its core, neither a single-temperature or double-temperature model nor the Gaussian-shaped differential emission measure model can accurately describe the input emission measure distribution of these massive objects. The largest effect of projection as well as resonant scattering was observed for projected profiles of iron abundance of NGC 4636, which is where we could reproduce the observed iron abundance drop in its innermost few kiloparsecs. Furthermore, we find that projection effects also influence the best-fit temperature, and the magnitude of this effect varies depending on the underlying hydrodynamical profiles of individual objects. In the core, the projection effects are the largest for A1795 and NGC 4636, while in the outskirts, the largest difference between 2D and 3D temperature profiles is for Perseus and A1795, regardless of the instrumental resolution. These findings might potentially have an impact on cross-calibration studies between different instruments as well as on the precision cosmology.