The South Pole Telescope (SPT) is a 10-meter millimeter-wavelength telescope located at the geographic South Pole, one of the world’s premier sites for millimeter-wave observations. The SPT has been used to conduct several generations of wide-field high resolution cosmic microwave background (CMB) surveys including the 2500-square-degree SPT-SZ survey, the SPTpol 500d and ECS surveys, and the...
The abundance of massive halos (and of the galaxy clusters they host) has long been recognized as an extremely promising probe of the large-scale structure of the universe. Over the past decade, tremendous progress was made, notably thanks to the availability of high-resolution surveys of the Cosmic Microwave Background (CMB), of high-quality measurements of gravitational lensing, and of...
The Simons Observatory is a ground-based cosmic microwave background (CMB) experiment being built on Cerro Toco in the Atacama Desert in Chile that promises to provide breakthrough discoveries in fundamental physics, cosmology, and astrophysics. I will review the design of the project, its science goals and schedule, and I will give a brief description of some of the analysis pipelines that...
Galaxy clusters are a powerful cosmological probe, being able to describe the latest evolution of large scale structure.
In recent years, cluster catalogs of thousands of objects have been detected in the mm wavelengths, through the thermal Sunyaev-Zeldovich effect.
In this talk I will show the results for the first combined analysis of clusters detected by the Planck satellite and the...
We report a high-precision detection of the cross-correlation of the thermal Sunyaev-Zel'dovich (tSZ) effect and gravitational lensing of the cosmic microwave background (CMB) using data from the Planck 2018 legacy release. This is only the second reported detection of this cross-correlation to date, following early work using the Planck nominal mission data (Hill & Spergel 2014). In our...
The Cosmic Microwave data at very small scales are known to probe not only primordial CMB fluctuations but also many extragalactic components such as tSZ, kSZ, CIB, points sources.
I will show how to use the cosmological dependent SZ signatures (tSZ and kSZ) at small scales coherently with the large scales and the cosmology framework in Planck and SPT experiments to retrieve both...
Class_sz is at the core of several pipelines for parameter inference in the Atacama Cosmology Telescope and the Simons Observatory. It enables a fast and accurate evaluation of SZ observables, such as the SZ power spectrum, cluster number counts and kinetic SZ cross-correlations, as well as cross and auto-correlations between a wide range of large-scale structure tracers, including CMB and...
Measuring the distribution of gas pressure in galaxy clusters is a key ingredient of cluster science, both from a cosmological and an astrophysical standpoint. Millimeter-wave observations offer highly valuable datasets for these measurements thanks to the thermal Sunyaev-Zeldovich (tSZ) effect, a spectral distorsion of the CMB with an amplitude directly proportional to the line of...
Three galaxy clusters selected from the XXL X-ray survey at high redshift and low mass (z ~ 1 and M500 ~ 1-2 x 10^14 Msun) were observed with NIKA2 to image their Sunyaev-Zel'dovich effect (SZE) signal. They all present an SZE morphology, together with the comparison with X-ray and optical data, that indicates dynamical activity related to merging events. Despite their disturbed intracluster...
It is broadly accepted that CO is a reliable tracer of molecular H in massive IR ($L_{\rm IR}\ \ge\ 10^9\ L_{\odot}$) galaxies, and that there are clear correlations between $L_{\rm IR}$ and $L'_{\rm CO}$ that are qualitatively independent of environment and even redshift. We present two tales on the search for $^{12}$CO emission from dusty star-forming galaxies in both field (Lockman Hole, z...
There are several new projects to survey the sky with millimetre eyes, the biggest being Simons Observatory and CMB-S4, in the Southern Hemisphere. The NIKA2 collaboration has acquired a knowledge sufficient to build a large focal plane KID camera for a 15-m antenna. This would allow covering the whole Northern Hemisphere in a couple of years at subarcminute resolution and with milliJansky...
CONCERTO (CarbON CII line in post-rEionization and ReionizaTiOn) is a low-resolution spectrometer with an instantaneous field-of-view of 18.6 arcmin, operating in the 130–310 GHz transparent atmospheric window. It is installed on the 12-meter Atacama Pathfinder Experiment (APEX) telescope at 5 100 m above sea level.
The Fourier transform spectrometer (FTS) contains two focal planes hosting a...
The leading theory to understand the initial conditions of the Big Bang is inflation, which predicts the existence of a primordial background of gravitational waves that must have left its imprint in the CMB polarization: the so-called B-modes. The main difficulty in measuring the B-mode polarization comes not just from its sheer faintness, but from the fact that many other objects in the...
Wide, deep, blind continuum surveys at submillimetre/millimetre (submm/mm) wavelengths are required to provide a full inventory of the dusty, distant Universe. However, conducting such surveys to the necessary depth, with sub-arcsec angular resolution, is prohibitively time-consuming, even for the most advanced submm/mm telescopes. In this talk, I will report the most recent results from the...
As demonstrated by Planck, ACT, and SPT, the abundance of tSZ-detected galaxy clusters across mass and redshift is a powerful cosmological probe. The upcoming Simons Observatory (SO) will lead to the detection of about 20 000 clusters, an order of magnitude more objects than what previous experiments found, thereby providing an unprecedented constraining potential. However, in order for this...
We use high sensitivity, beam-matched APEX, ALMA, and ACA (sub)-mm observations to study the state of the cold molecular gas in a sample of ~40 local ultra luminous infrared galaxies (ULIRGs), hence probing mostly galaxy mergers characterized by strong starburst and AGN activity. We aim to understand how such energetic feedback processes affect the kinematics and excitation of the molecular...
An all-sky map of the thermal Sunyaev-Zeldovich (SZ) effect has been publicly released by the Planck Collaboration in 2015, using a Needlet Internal Linear Combination (NILC) component separation method on Planck PR2 data. The quality of the Planck data has improved since then. The Planck PR4 data release provides full-sky maps in LFI and HFI frequency bands with improved systematics and...
Over the last year, we have witnessed a mad dash as the community tries to confirm candidate z>10 galaxies identified through HST and JWST photometry. Multiple ALMA DDT observations have been conducted, targeting the [OIII] 88 micron (and [CII] 158 micron) emission of these candidates, with the aim of securing their redshifts. But, at the time of this abstract submission, none of these...
Galaxy clusters are a powerful cosmological probe: they track the latest evolution of large scale structure and are therefore fundamental for testing the cosmological model in the recent Universe. To compare the observations of galaxy clusters with the theoretical prediction and thus constrain the cosmological parameters of the underlying model, a precise knowledge of clusters’ masses and...
Despite recent discoveries of quasar feedback in action through outflows and jets, the amount of energy that the active nucleus is capable of injecting into the extended interstellar medium of the host galaxy remains unknown. The most mysterious component of quasar feedback is the lowest density, hot volume-filling gas. Though there are tentative detections of this component via its thermal...
Assuming spherical symmetry, joint X-ray and millimetre observations of galaxy cluster atmospheres allow us to measure intra-cluster distances. Using XMM-Newton and Planck observations of CHEX-MATE galaxy clusters, we investigate the relationship between X-ray and X-ray+mm inferences of cluster temperature profiles. The average ratio between X-ray and X-ray+mm temperatures,...
Since the first (sub)mm observations, it has been clear that the cosmic census of high-z galaxies based on deep optical/NIR surveys is quite far from complete. The "darkest galaxies", in which significant amounts of dust absorb the stellar emission, are missed by these surveys, even though their contribution to the cosmic Star Formation Rate Density and to the evolution of massive galaxies is...
Strong lensing galaxy clusters provide a powerful observational test of Cold Dark Matter (CDM) structure predictions derived from simulation. Specifically, the shape and relative alignments of the dark matter halo, stars, and hot intracluster gas tells us the extent to which theoretical structure predictions hold for clusters in various dynamical states. We measure the position angles,...
Galaxies in voids have experienced a different environment than non-void galaxies during their entire existence. Their properties are possibly different from non-void galaxies, however, systematic studies have been missing for a long time. The Legacy Survey CAVITY (Calar Alto Void Treasury Integral-field Survey) aims to fill this gap. It will observe about 300 carefully selected void galaxies...
One of the main challenges of the next generation of cosmic microwave background (CMB) experiments is probing the primordial gravitational waves signal that have left an imprint in the curly pattern (a.k.a B -modes) of the CMB polarization. This very weak signal, if detected, will probe the existence of the inflation era and open the path to a physics beyond the standard model.
This goal has...
In our previews works, deep learning techniques have succeeded in estimating galaxy cluster masses in observations of Sunyaev Zel'dovich maps, e.g. in the Planck PSZ2 catalog and mass radial profiles from SZ mock maps. In the next step, we explore inferring 2D mass density from mock observations of SZ, X-ray and stars using THE THREE HUNDRED (The300) cosmological simulation. In order to do...
The MIllimeter Sardinia radio Telescope Receiver based on Array of Lumped elements kids (MISTRAL) is a millimetric total power camera operating at 90 GHz installed at the Sardinia Radio Telescope (SRT). MISTRAL provides a wide 4’ field of view, sampled at a resolution of 12’’ with ~400 Kinetic Inductance Detectors. After technical and scientific commissioning (planned for 2023), MISTRAL will...
In Sunyaev Zeldovich (SZ) cluster cosmology, one of the main parameter of interest is cluster mass. It is needed to constrain cosmological parameters through the cluster number count. As the mass is not an observable, a scaling relation is needed to link cluster masses to the integrated Compton parameters Y, i.e the SZ observable.
Current cosmological results use the Planck scaling...
We present the results of a study on the feasibility of upgrading the existing ALMA Band 9 receivers (602-720 GHz). In the current configuration, each receiver is a dual channel heterodyne system capable of detecting orthogonally polarized signals through the use of a wire grid and a compact arrangement of mirrors. The main goals of the study are the upgrade of the mixer architecture from...
In this talk, I will present the Baryon Pasting project, which aims to develop a physically-motivated, computationally efficient model for large multi-wavelength cosmological surveys (including microwave, X-ray and optical skies). I will discuss the current status, challenges, and future prospects of forward-modeling multi-wavelength cosmological surveys and enabling cross-survey,...
Galaxy cluster-based cosmology is at a crossroads, with the current and next-generation surveys delivering deep sky surveys and large cluster catalogs. In this framework, the use of simulations to calibrate systematics in cosmological analyses is crucial. As a large proportion of cosmological simulations are gravity-only (effectively only evolving dark matter particles), the exploitation of...
The Cluster HEritage project with XMM-Newton – Mass Assembly and Thermodynamics at the Endpoint of structure formation (CHEX-MATE)
is a three-mega-second Multi-Year Heritage Programme to obtain X-ray observations of a minimally-biased, signal-to-noise-limited sample of 118 galaxy clusters detected by Planck through the Sunyaev–Zeldovich effect. The program aims to study the ultimate products...
The X-ray spectrum of extragalactic sources, such as galaxy clusters, is affected by the photo-absorption of various components of the Galactic InterStellar Medium (ISM). The resulting spectral distortion contributes to the systematics of cluster temperature measurements. It essentially depends on the total (atomic+molecular) Galactic hydrogen density column, N_H, which remains challenging to...
The gas mass fraction in galaxy clusters is a convenient probe to use in cosmological studies, as it can help derive constraints on a collection of cosmological parameters.
It is however subject to various effects from the baryonic physics inside galaxy clusters, which may bias the obtained cosmological constraints.
Among different aspects of the baryonic physics, in this presentation I...
Over the past decade, the kinetic SZ effect has emerged as a probe of the distribution of baryons and the large-scale velocity field in the late Universe. Of the several ways to detect it, the so-called Projected-Fields kSZ estimator has the promising characteristic of not being limited to spectroscopic samples of galaxies. The original theoretical formulation of this estimator included...
The Sunyaev-Zel’dovich Effect—the Doppler boost of low-energy Cosmic Microwave Background photons scattering off free electrons—is an excellent probe of ionized gas residing in distant galaxies. Its two constituents are the kinematic SZ effect (kSZ), where electrons have a non-zero line-of-sight (LOS) velocity and which probes the electron line-of-sight momentum, and the thermal SZ effect...
Extracting the kinematic Sunyaev-Zel'dovich (kSZ) effect—the Compton scattering of CMB photons off moving electrons—requires cleaning of other sky components. In this work, we use large-scale structure (LSS) tracers that are correlated with both the cosmic infrared background (CIB) and thermal Sunyaev-Zel'dovich (tSZ) signal, but whose two-point correlations with the kSZ signal vanish on small...
In recent years there have been an increasing amount of studies on the overdensities of galaxies in the distant Universe, even beyond a redshift of z>4. However, how these so-called protoclusters evolve from a structure stretching several hundreds of Mpc to a bonafide galaxy cluster and how these distant clusters of galaxies differ from local ones are still open questions in modern...
The South Pole Telescope (SPT) is observing the cosmic microwave background (CMB) anisotropies with arcminute resolution using its state-of-the-art camera (SPT-3G). Upcoming constraints on cosmological constraints from power spectrum analyses with the 2019/2020 data will be at least as tight as Planck’s ones, while remaining independent from the satellite experiment, thus allowing to test the...
Local primordial non-Gaussianity, parametrized by $f_{NL}^{\mathrm{loc}}$, induces a characteristic scale dependence in the large-scale bias of halos. This scale dependence is a promising path to constrain multi-field inflation theories, which predict non-zero $f_{NL}^{\mathrm{loc}}$. We use the cosmic infrared background (CIB), measured by $\textit{Planck}$, which is sourced by thermal...
Until now, direct observations of the intracluster medium (ICM) have been limited only to mature clusters in the latter three-quarters of the history of the Universe, and we have been lacking a direct view of the hot, thermalised cluster atmosphere beyond z~2, the epoch when the first massive clusters formed. Probing the thermal evolution of cosmic structures through z~2 — the epoch when...
The Three Hundreds project consists of a 324 regions sample simulated with full-physics hydrodynamical re-simulations. They have been produced starting from the dark-matter-only MultiDark Simulations [MDPL2 8], which consists in a 1 h$^{-1}$ Gpc cube containing 3840$^3$ dark matter (DM) particles with a mass of $1.5 \times 10^9$ h$^{-1}$ M$_\odot$ each (LR DMONLY). This produces 324...
Galaxy mergers are known to be one of the major paths through which galaxies evolve across cosmic time, therefore it is absolutely necessary to study such systems at different redshifts to further our understanding of galaxy evolution. Significant progress has been made in the last decades thanks to HST, although a remaining challenge is the presence of obscuring dust, which can make one or...
Filaments connecting galaxy clusters in the Cosmic Web are thought to quantify, or to simply have an impact on several intrinsic and observational properties of the halos. From the gas filamentary structure of the 324 simulated regions of The Three Hundred project extracted with the DisPerSE filament finder at z=0, we estimate the connectivity, the number of filaments to which clusters are...
I will present a morphological analysis of a set of spiral galaxies from the NIKA2 Guaranteed Time Large Program, IMEGIN, by fitting simultaneously a single Sérsic model on broadband images, from UV to millimeter (mm) wavelengths, using the multiband modelling code GALFITM. With the recently acquired NIKA2 1.2- and 2-mm observations, it is possible to extend such a morphological analysis to...
Supernova (SN) explosions are important for galaxy evolution because they enrich the interstellar medium with heavy elements and provide feedback which can halt further star formation. These effects depend on what stellar progenitors explode as a given SN type. Type Ic SNe (without hydrogen or helium lines in their spectra) can either be a binary system of ~10 solar mass stars or a very...
We develop a machine learning algorithm that infers the radial profiles of total and gas mass of galaxy clusters given thermal Sunyaev-Zeldovich (SZ) effect maps. The architecture is composed of a combination of an autoencoder and a random forest. The first is used to extract the information from the maps, while the second performs the final estimation of the radial mass profiles. This ML...
Interstellar dust (ISD) grains are solid particles made of heavy elements (e.g., O, C, Si, Mg, Fe) available in the Interstellar Medium (ISM), with sizes ranging typically from 0.3 nm to 0.3 $\mu$m, and rather uniformly mixed with the gas. Although accounting just for 1% of the ISM mass, they have a radical impact on galaxy emission, since they scatter and absorb starlight, and re-radiate at...
The Balloon-borne Large Aperture Submillimeter Telescope Observatory (BLAST Observatory) is a proposed NASA super-pressure balloon mission. BLAST Observatory will include a 1.8 m off-axis primary mirror and observe at 175, 250, and 350 microns simultaneously, with a total of 8274 polarization-sensitive microwave kinetic inductance detectors (MKIDs) cooled to 100 mK. The telescope will be...
Here I will describe progress with AtLAST, a wide field of view (1-2 degree), 50-meter aperture single dish telescope that will be located at over 5000 meters above sea level, high in the Atacama Desert. AtLAST will accommodate a vast range of large (2 to 4.5 meter diameter) instruments operating from 30 GHz to 1 THz in a cabin that enables expedient switching between receivers. AtLAST will...
The central molecular zone (CMZ) of our Galaxy hosts an extreme interstellar environment analogous to that found in typical starburst galaxies in the distant Universe. In order to understand dust properties in such environments, we have conducted a survey of the CMZ with the AzTEC/Large Millimeter Telescope (LMT) in the 1.1 mm continuum. This survey has been analyzed together with...
Understanding the evolution of dust properties in molecular clouds is important for tracing the star formation process through submm observations. We aim at constraining the evolution of dust grains from star-forming filaments to prestellar and protostellar cores to T Tauri stars. Using the NIKA2 continuum camera on the IRAM 30~m telescope, we observed the Taurus B211/B213 filament in the...
An accurate mass calibration of galaxy clusters is a crucial step towards precise constraints on the cosmological parameters $\sigma_8$ and $\Omega_m$ from clusters. In the millimeter, via the Sunyaev-Zel'dovich (SZ) effect, and X-rays domains, cluster masses can be estimated assuming hydrostatic equilibrium, but several physical and observational effects can alter this calculation. One of...
Cosmic Microwave Background experiments need to measure instrumental systematics very accurately to achieve their scientific goals. As a result of that, it is necessary to properly characterize these telescopes. However, natural sources cannot be used to calibrate all the properties of the instrument but we need to complement these with artificial sources. For this reason, we developed the...
I will present a nodal approach to recovering the fundamental properties of galaxy clusters like pressure, density, and temperature. The method involves constructing piecewise functions that describe the quantities of galaxy clusters through a set of control points, which are inferred using a non-parametric Bayesian analysis. I will show an application of this method to the analysis of Planck...
Kinetic inductance detectors carry the promise of a truly scalable detector solution, providing a practical path to filling the large and densely populated focal planes envisioned for future far-infrared and millimeter-wave instruments. At the same time, this detector technology shows promise in meeting the ambitious sensitivity and dynamic range specifications required to achieve the next...
The total mass of a cluster is one of its most fundamental properties. Measurements of the galaxy cluster mass often relies upon assuming hydrostatic equilibrium. However, this is often invalidated as the intracluster medium (ICM) is continuously disturbed by mergers, feedback processes, and motions of galaxies. These processes generate gas motions that contribute nonthermal pressure;...
The Q\&U Bolometric Interferometer for Cosmology (QUBIC) is the first bolometric interferometer to measure the primordial B-mode polarization of the Cosmic Microwave Background (CMB).
Bolometric interferometry is a novel technique that combines the sensitivity of bolometric detectors with the control of systematic effects that is typical of interferometry, which are both key features in...
TolTEC is a polarization-sensitive camera at millimeter wavelengths with unprecedented sensitivity at 5-11 arcsecond resolution in three photometric bands. TolTEC achieved first-light on the 50 meter Large Millimeter Telescope in July 2022 just prior to a planned summer telescope maintenance shutdown, and began commissioning observations when the telescope resumed observations in December...
The Zernike polynomials has been recently used to model 2D projection maps of galaxy clusters to recover their morphological features. The study of the morphology of clusters maps is, in fact, a well suited approach used to infer, from real data, the dynamical state of those systems. After the validation of the Zernike polynomials as suitable tools to constrain galaxy clusters morphologies,...
Galaxy clusters trace the highest peaks in the density of the Universe. Therefore, their abundance is a powerful probe to constrain cosmological parameters, expansion of the Universe and give information on the growth of structures. However, since the density of galaxies is significantly higher, these latter may appear to overlap on the line of sight and have their respective fluxes blended....
The thermal Sunyaev-Zel’dovich effect refers to a spectral distortion in the cosmic microwave background (CMB) due to the inverse-Compton scattering of CMB photons off free, energetic electrons present in the Universe. It is primarily sourced by the electrons in the intracluster medium with smaller contributions from the intergalactic medium and the epoch of reionization. The amplitude of its...
Weak gravitational lensing is a powerful tool to probe the matter distribution around massive galaxy clusters. In general, such effect can be measured by estimating the averaged tangential shear of background galaxies in circular annuli around the lens center. In addition to the average tangential shear, valuable information on the underlying dark matter distribution can be extracted by using...
The measurement of the Cosmic Microwave Background spectrum made by COBE/FIRAS in the 1990s showed that the CMB spectral energy distribution is close to a perfect blackbody. However, the CMB spectrum contains tiny departures from a perfect blackbody to $\Delta I/I \simeq 10^{-5}$, referred to as spectral distortions. CMB spectral distortions encode information about the full thermal history of...
In the quest for the faint primordial B-modes of the Cosmic Microwave
Background, three are the key features for any present or future experiment: an utmost sensitivity, excellent control over instrumental systematic effects and over Galactic foreground contamination.
Bolometric Interferometry (BI) is a novel technique that matches them all by combining the sensitivity from bolometric...
Accurate reconstruction of galaxy cluster masses is key to use this population of objects as cosmological probe. In this work we present a study on the hydrostatic to lensing mass scaling relation for a sample of 53 clusters, with redshifts from z = 0.05 to 1.07, for which masses have been reconstructed homogeneously. Masses for each individual cluster have been measured from reconstructed...
We present a detailed study of the surface brightness profiles derived from a representative sample of 118 clusters selected via the Sunyaev-Zel'Dovich effect. These profiles represent an ideal tool to investigate the properties of the hot plasma filling the cluster volume. Studies of these profiles have been hampered by selection biases and faintness of the emission in the outskirts. We...
At temperatures above ~5 keV, the non-relativistic approximation used to derive the classical thermal Sunyaev-Zel'dovich effect spectrum begins to fail. When relativistic effects are included, the spectrum becomes temperature-dependent. This leads to both a problem and an opportunity: a problem, because when the temperature dependence is not accounted for the Compton-y estimate is biased;...
I will discuss how current (with XMM-Newton) and future X-ray observations (with XRISM and Athena) will be able to characterize the non-thermal pressure support in galaxy clusters, and how we can convert it in an estimate of the hydrostatic mass bias, also for a cosmological purpose.
A new window into the growth and evolution of large-scale structure
has opened up with the recent observations of the thermal and kinetic
Sunyaev-Zel’dovich (SZ) effects. I will review recent observations of
the SZ signals and highlight their expected rapid growth over the next
decade with upcoming cosmic microwave background experiments, like
Simons Observatory and CMB-S4. I will present...
Observing galaxies in millimeter continuum emission is vital to study the physical properties of the dusty interstellar medium as it provides constraints on the low-frequency end of the dust spectral energy distribution (SED). We present observations of NGC2146 (starburst spiral) and NGC2976 (peculiar dwarf) with the NIKA2 camera on the IRAM-30m telescope, as part of the IMEGIN guaranteed time...
High resolution observations of nearby galaxies at mm wavelengths allow us to study emission from interstellar medium in great detail. In the framework of the IMEGIN Large program, the NIKA2 camera on the IRAM 30-m telescope is used to map 22 nearby galaxies at 1.15 and 2 mm and at resolutions of 11.1" and 17.6", respectively. At these wavelengths we are able to trace the emission from very...
In this talk we report upon results the intracluster medium (ICM) of two galaxy clusters at the time the first objects start to emerge from the cosmic web, z~2. Results are derived from new high resolution, deep SZ and X-ray data providing us with the measurement of the two most distant resolved pressure profiles. IDCSJ1426 cluster at z=1.75 has a core whose properties has likely reached the...
The strong gravitational lensing regime provides a unique probe of structure formation in the Universe. There has been significant effort to identify and characterize strong lensing clusters selected in the X-ray and optical wavelengths; here we extend such studies to a large sample of strong lensing clusters identified by the Sunyaev Zel'dovich (SZ) effect in >5,000 square degrees of South...
The Doppler boosting of cosmic microwave background (CMB) photons due to scattering off free electrons produces the Kinematic Sunyaev-Zeldovich (kSZ) effect. It offers a unique way to probe the epoch of reionisation. However, the kSZ signal is sub-dominant to other astrophysical signals, in particular the emission from dusty star forming galaxies that form the diffuse component of the cosmic...
Cosmological constraints from galaxy clusters are currently limited by the precision of mass estimation. Non-thermal pressure support is suspected to be the primary culprit in biasing mass estimations from the intracluster medium (ICM). Moreover, (quasi-)turbulent gas motions are thought to be the dominant source of non-thermal pressure, in which case high resolution X-ray spectrographs on...
