We study the connection between morphology and dynamical state of the simulated galaxy clusters in $z\in[0,1.031]$ from THE THREE HUNDRED Project. We quantify cluster dynamical state using a combination of dynamical indicators from theoretical measures and compare this combined parameter, $χ$, with the results from morphological classifications. The dynamical state of the cluster sample shows a continuous distribution from dynamically relaxed, more abundant at lower redshift, to hybrid and disturbed. The dynamical state presents a clear dependence on the radius, with internal regions more relaxed than outskirts. The morphology from multi-wavelength mock observation of clusters in X-ray, optical, and Sunyaev-Zel'dovich (SZ) effect images, is quantified by $M$ -- a combination of six parameters for X-ray and SZ maps and the offsets between the optical position of the Brightest Central Galaxy (BCG) and the X-ray/SZ centroids. All the morphological parameters are highly correlated with each other, while they show a moderately strong correlation with the dynamical $χ$ parameter. The X-ray or SZ peaks are less affected by the dynamical state than centroids, which results in reliable tracers of the cluster density peak. The principal source of contamination in the relaxed cluster fraction, inferred from morphological parameters, is due to dynamically hybrid clusters. Compared to individual parameters, which consider only one aspect of cluster property (e.g. only clumping or asymmetry), the combined morphological and dynamical parameters ($M$ and $χ$) collect more information and provide a single and more accurate estimation of the cluster dynamical state.
The knowledge of the dynamical state of galaxy clusters allows to alleviate systematics when observational data from these objects are applied in cosmological studies. Evidence of correlation between the state and the morphology of the clusters is well studied. The morphology can be inferred by images of the surface brightness in the X-ray band and of the thermal component of the Sunyaev-Zel'dovich (tSZ) effect in the millimetre range. For this purpose, we apply, for the first time, the Zernike polynomial decomposition, a common analytic approach mostly used in adaptive optics to recover aberr…
The study of galaxies has changed dramatically over the past few decades with the advent of large-scale astronomical surveys. These large collaborative efforts have made available high-quality imaging and spectroscopy of hundreds of thousands of systems, providing a body of observations which has significantly enhanced our understanding not only of cosmology and large-scale structure in the universe but also of the astrophysics of galaxy formation and evolution. Throughout these changes, one thing that has remained constant is the role of galaxy morphology as a clue to understanding galaxies. …
We look at the morphology of fast and slow rotator early-type galaxies. Edge-on fast rotators are lenticular galaxies. They appear like spiral galaxies with the gas and dust removed, and in some cases are flat ellipticals with disky isophotes. Fast rotators are often barred and span the same full range of bulge fractions as spiral galaxies. The slow rotators are rounder and are generally consistent with being genuine, namely spheroidal-like, elliptical galaxies. We propose a revision to the tuning-fork diagram by Hubble as it gives a misleading description of ETGs. We study for the first time …
Several methods are used to evaluate, from observational data, the dynamical state of galaxy clusters. Among them, the morphological analysis of cluster images is well suited for this purpose. We report a new approach to the morphology, which consists in analytically modelling the images with a set of orthogonal functions, the Zernike polynomials (ZPs). We validated the method on mock high-resolution Compton parameter maps of synthetic galaxy clusters from THE THREE HUNDRED project. To classify the maps for their morphology we defined a single parameter, $\mathcal{C}$, by combining the contrib…
Gradient pattern analysis (GPA) is a well-established technique for measuring gradient bilateral asymmetries of a square numerical lattice. This paper introduces an improved version of GPA designed for galaxy morphometry. We show the performance of the new method on a selected sample of 54,896 objects from the SDSS-DR7 in common with Galaxy Zoo 1 catalog. The results suggest that the second gradient moment, G2, has the potential to dramatically improve over more conventional morphometric parameters. It separates early from late type galaxies better (\sim 90\%) than the CAS system (C \sim 79\%,…
Hydrostatic equilibrium (HE) is often used in observations to estimate galaxy clusters masses. We use a set of almost 300 simulated clusters from The Three Hundred Project, to estimate the cluster HE mass and the bias deriving from it. We study the dependence of the bias on several dynamical state indicators across a redshift range from 0.07 to 1.3, finding no dependence between them. Moreover, we focus our attention on the evolution of the HE bias during the merger phase, where the bias even reaches negative values due to an overestimation of the mass with HE.
Using 324 numerically modelled galaxy clusters we investigate the radial and galaxy-halo alignment of dark matter subhaloes and satellite galaxies orbiting within and around them. We find that radial alignment depends on distance to the centre of the galaxy cluster but appears independent of the dynamical state of the central host cluster. Furthermore, we cannot find a relation between radial alignment of the halo or galaxy shape with its own mass. We report that backsplash galaxies, i.e. objects that have already passed through the cluster radius but are now located in the outskirts, show a s…
Using 324 numerically modelled galaxy clusters as provided by THE THREE HUNDRED project, we study the evolution of the kinematic properties of the stellar component of haloes on first infall. We select objects with M$_{\textrm{star}}>5\times10^{10} h^{-1}M_{\odot}$ within $3R_{200}$ of the main cluster halo at $z=0$ and follow their progenitors. We find that although haloes are stripped of their dark matter and gas after entering the main cluster halo, there is practically no change in their stellar kinematics. For the vast majority of our `galaxies' -- defined as the central stellar component…
We perform a systematic study of the recently discovered fundamental plane of galaxy clusters (CFP) using ~250 simulated clusters from The Three Hundred project, focusing on the stability of the plane against different temperature definitions and its dependence on the dynamical relaxation state of clusters. The CFP is characterised by $T\propto M_\mathrm{s}^α\,r_\mathrm{s}^β$, defined with the gas temperature ($T$) and the characteristic halo scale radius and mass ($r_\mathrm{s}$ and $M_\mathrm{s}$) assuming a Navarro-Frenk-White halo description. We explore two definitions of weighted tempera…
We analyse the gas content evolution of infalling haloes in cluster environments from THE THREE HUNDRED project, a collection of 324 numerically modelled galaxy clusters. The haloes in our sample were selected within $5R_{200}$ of the main cluster halo at $z=0$ and have total halo mass $M_{200}\geq10^{11} h^{-1} M_{\odot}$. We track their main progenitors and study their gas evolution since their crossing into the infall region, which we define as $1-4R_{200}$. Studying the radial trends of our populations using both the full phase space information and a line-of-sight projection, we confirm t…
Galaxy clusters have a triaxial matter distribution. The weak-lensing signal, an important part in cosmological studies, measures the projected mass of all matter along the line-of-sight, and therefore changes with the orientation of the cluster. Studies suggest that the shape of the brightest cluster galaxy (BCG) in the centre of the cluster traces the underlying halo shape, enabling a method to account for projection effects. We use 324 simulated clusters at four redshifts between 0.1 and 0.6 from `The Three Hundred Project' to quantify correlations between the orientation and shape of the B…
We develop a machine learning algorithm to infer the 3D cumulative radial profiles of total and gas mass in galaxy clusters from thermal Sunyaev-Zel'dovich effect maps. We generate around 73,000 mock images along various lines of sight using 2,522 simulated clusters from the \thethreehundred{} project at redshift $z< 0.12$ and train a model that combines an autoencoder and a random forest. Without making any prior assumptions about the hydrostatic equilibrium of the clusters, the model is capable of reconstructing the total mass profile as well as the gas mass profile, which is responsible for…
The Three Hundred Project: Validating $H_0$ inference from mock X-ray and millimetre analyses of galaxy clusters
Università di Roma ‘Tor Vergata’（罗马托尔维加塔大学）；INFN, Sezione di Roma ‘Tor Vergata’（罗马托尔维加塔意大利国家核物理研究所）；INAF - Osservatorio Astronomico di Trieste（的里雅斯特天文台意大利国家天体物理研究所）；IFPU, Institute for Fundamental Physics of the Universe（宇宙基础物理研究所）；University of Michigan（密歇根大学）；Universidad Autónoma de Madrid（马德里自治大学）；Sapienza Università di Roma（罗马智慧大学）
We introduce the "Bluedisk" project, a large program at the Westerbork Synthesis Radio Telescope (WSRT) that has mapped the HI in a sample of 23 nearby galaxies with unusually high HI mass fractions, along with a similar-sized sample of control galaxies matched in stellar mass, size, inclination and redshift. This paper presents the sample selection, observational set-up, data reduction strategy, and a first analysis of the sizes and structural properties of the HI disks. We find that the HI-rich galaxies lie on the same HI mass versus HI size relation as normal spiral galaxies, extending it t…
We present the Atlas3D HI survey of 166 nearby early-type galaxies (ETGs) down to M(HI)~10^7 M_sun. We detect HI in ~40% of all ETGs outside the Virgo cluster and in ~10% of all ETGs inside it. This demonstrates that it is common for non-cluster ETGs to host HI. The HI morphology varies from regular discs/rings (the majority of the detections) to unsettled gas distributions. The former are either small discs (M(HI)<10^8 M_sun) confined within the stellar body and sharing the same kinematics of the stars, or large discs/rings (M(HI) up to 5x10^9 M_sun) extending to tens of kpc from the host gal…
Dark matter-only simulations are able to produce the cosmic structure of a $Λ$CDM universe, at a much lower computational cost than more physically motivated hydrodynamical simulations. However, it is not clear how well smaller substructure is reproduced by dark matter-only simulations. To investigate this, we directly compare the substructure of galaxy clusters and of surrounding galaxy groups in hydrodynamical and dark matter-only simulations. We utilise TheThreeHundred project, a suite of 324 simulations of galaxy clusters that have been simulated with hydrodynamics, and in dark matter-only…
We perform high-resolution (15-30 pc) adaptive mesh simulations to study the impact of momentum-driven AGN feedback in cool-core clusters, focusing in this paper on the formation of cold clumps. The feedback is jet-driven with an energy determined by the amount of cold gas within 500 pc of the SMBH. When the intra-cluster medium (ICM) in the core of the cluster becomes marginally stable to radiative cooling, with the thermal instability to the free-fall timescale ratio t_{TI}/t_{ff} < 3-10, cold clumps of gas start to form along the propagation direction of the AGN jets. By tracing the particl…
We investigate the relation between the projected morphology (b/a) and the velocity dispersion (sigma_v) of groups of galaxies using two recently compiled group catalogs, one based on the 2MASS redshift survey and the other on the SDSS Data Release 5 galaxy catalog. We find that the sigma_v of groups is strongly correlated with the group projected b/a and size, with elongated and larger groups having a lower sigma_v. Such a correlation could be attributed to the dynamical evolution of groups, with groups in the initial stages of formation, having small sigma_v, a large size and an elongated sh…
The AGORA High-resolution Galaxy Simulations Comparison Project. XI: Solving the Non-Spherical Morphology and Evolution of Dark Matter Halos with Haskap Pie
University of Illinois Urbana-Champaign（伊利诺伊大学厄巴纳-香槟分校）；Lund University（隆德大学）；Seoul National University（首尔大学）；Osaka University（大阪大学）
Accurate and precise measurements of masses of galaxy clusters are key to derive robust constraints on cosmological parameters. Rising evidence from observations, however, confirms that X-ray masses, obtained under the assumption of hydrostatic equilibrium, might be underestimated, as previously predicted by cosmological simulations. We analyse more than 300 simulated massive clusters, from `The Three Hundred Project', and investigate the connection between mass bias and several diagnostics extracted from synthetic X-ray images of these simulated clusters. We find that the azimuthal scatter me…
Using the data set of The Three Hundred project, i.e. a suite of 324 hydrodynamical resimulations of cluster-sized haloes, we study galaxy cluster mergers and their effect on colour and luminosity changes of their brightest cluster galaxies (BCG). We track the main progenitor of each halo at z=0 and search for merger situations based on its mass accretion history, defining mergers as very rapid increases in the halo mass. Based upon the evolution of the dynamical state of the cluster we define a pre- and post-merger phase. We create a list of all these events and statistically study their mass…
In light of recent findings from the kinematic morphology-density relation, we investigate whether the same trends exist in the original morphology density relation, using the same data as Dressler. In addition to Dressler's canonical relations, we find that further refinements are possible when considering the average local projected density of galaxies in a cluster. Firstly, the distribution of ellipticals in a cluster depends on the relative local density of galaxies in that cluster: equivalent rises in the elliptical fraction occur at higher local densities for clusters with higher average…
For decades, the nuclear starburst has taken all the limelight in M82 with very little discussion on M82 as a galaxy. The situation is changing over the last decade, with the publication of some important results on the morphology and stellar content of its disk and halo. In this review, we discuss these recent findings in the framework of M82 as a galaxy. It is known for almost half a century that M82 as a galaxy doesn't follow the trends expected for normal galaxies that had prompted the morphologists to introduce a separate morphological type under the name Irr II or amorphous. It is now be…
The Three Hundred project: cosmic web identification from 2D gas and Compton-$y$ maps of galaxy clusters outskirts
Sapienza Università di Roma（罗马第一大学）；Universidad Autónoma de Madrid（马德里自治大学）；Centro de Investigación Avanzada en Física Fundamental (CIAFF)（基础物理高级研究中心）；University of Edinburgh（爱丁堡大学）；Universidad Rey Juan Carlos（雷乌斯·胡安·卡洛斯国王大学）；Università degli Studi di Napoli Federico II（那不勒斯费德里科二世大学）
The results from a large field Far-Infrared (FIR) and sub-millimeter (sub-mm) survey of our neighbor galaxy M31 are presented. We have obtained Herschel images of a ~5.5x2.5 degree area centered on Andromeda. Using 21 cm atomic hydrogen maps, we are able to disentangle genuine emission from M31 from that for foreground Galactic cirrus, allowing us to recognize dusty structures out to ~31 kpc from the center. We first characterize the FIR and sub-mm morphology and then, by de-projecting Herschel maps and running an ad--hoc source extraction algorithm, we reconstruct the intrinsic morphology and…
We present sub-mm continuum and heterodyne data of the interacting galaxy NGC 3627, obtained with the HHT and APEX. We find significant changes in the molecular line ratios over small scales in the southeastern part of this galaxy. The kinematics of the CO(2-1) line, as well as the morphology in the 870um continuum emission, suggest a continuation of the western spiral arm on the east side of the galaxy's central area. This continued spiral arm crosses the normal eastern spiral arm in an area which shows an unusual magnetic field configuration. This spiral arm crossing, independently of if it'…
The Three Hundred project: Low Gas Fraction Galaxy Clusters properties and their environment
Sapienza Università di Roma（罗马第一大学）；INAF-Osservatorio Astronomico di Roma（罗马天文台）；Universidad Autónoma de Madrid（马德里自治大学）；Università degli Studi di Napoli "Federico II"（那不勒斯费德里科二世大学）；Université Paris-Saclay（巴黎萨克雷大学）；INAF–Osservatorio Astronomico di Brera（布雷拉天文台）
Gamma-rays provide a powerful insight into the non-thermal universe and perhaps a unique probe for new physics beyond the standard model. Current experiments are already giving results in the physics of acceleration of cosmic rays in supernova remnants, pulsar and active galactic nuclei with almost a hundred sources detected at very-high-energies so far. Despite its relatively recent appearance, very high-energy gamma-ray astronomy has proven to have reached a mature technology with fast assembling, relatively cheap and reliable telescopes. The goal of future installation is to increase the se…
Close pairs of galaxies have been broadly studied in the literature as a way to understand galaxy interactions and mergers. In observations they are usually defined by setting a maximum separation in the sky and in velocity along the line of sight, and finding galaxies within these ranges. However, when observing the sky, projection effects can affect the results, by creating spurious pairs that are not close in physical distance. In this work we mimic these observational techniques to find pairs in The Three Hundred simulations of clusters of galaxies. The galaxies' 3D coordinates are project…
Hybrid morphology radio sources are a rare type of radio galaxy that display different Fanaroff-Riley classes on opposite sides of their nuclei. To enhance the statistical analysis of hybrid morphology radio sources, we embarked on a large-scale search of these sources within the international citizen science project, Radio Galaxy Zoo (RGZ). Here, we present 25 new candidate hybrid morphology radio galaxies. Our selected candidates are moderate power radio galaxies (L_median = 4.7x10^{24} W/(Hz sr) at redshifts 0.14<z<1.0. Hosts of nine candidates have spectroscopic observations, of which six …
The Lumina Project: Morphology of Ionized Bubbles and Neutral Islands
Massachusetts Institute of Technology（麻省理工学院）；The University of Texas at Dallas（德克萨斯大学达拉斯分校）；Philipps Universität Marburg（马尔堡菲利普斯大学）；Max Planck Institute for Astrophysics（马克斯·普朗克天体物理研究所）；York University（约克大学）
Halo mass, star formation, and morphology in galaxies: A morphology-dependent connection between halo environment and star formation activity
Instituto de Fisica de Cantabria (CSIC-Universidad de Cantabria)（坎塔布里亚物理研究所（西班牙科学研究中心-坎塔布里亚大学））；University of Southampton（南安普顿大学）；National Observatory of Athens（雅典国家天文台）
