In this work we have studied the relationship between the kinematics and shapes of Early Type Galaxies (ETGs) in rich clusters. In particular we were interested to extend the kinematic morphology density relation to the richest clusters. We obtained data from FLAMES/GIRAFFE to probe the stellar kinematics of a sample of 30 ETGs in the massive cluster Abell 1689 at z = 0.183, to classify them as Slow Rotators (SRs) or Fast Rotators (Frs). To date, this is the highest redshift cluster studied in this way. We simulated FLAMES/GIRAFFE observations of the local SAURON galaxies to account for the bias introduced compared to the ATLAS3D sample, which we used as a local comparison. We find that the luminosity function of SRs in Abell 1689 is the same as that in ATLAS^3D, down to the faintest objects probed (M_K ≈ -23). The number fraction of SRs over the ETG population in Abell 1689 is f_SR = 0.15 +/- 0.03, consistent with the value found in the Virgo Cluster. However, within the cluster, f_SR rises sharply with the projected number density of galaxies, rising from f_SR = 0.01 in the least dense bin to f_SR = 0.58 in the densest bin. We conclude that the fraction of SRs is not determined by the local number density of galaxies, but rather by the physical location within the cluster. This might be due to dynamical processes which cause SRs (on average more massive) to sink in the gravitational potential of the cluster. Next we explore the distribution of projected ellipticity &epsilon; in galaxies belonging to a sample of clusters from SDSS (z </~ 0.1) and the CLASH survey (z ≈ 0.2). We were interested to establish whether the fraction of galaxies flatter than &epsilon; = 0.4 (a proxy for FRs) varies from cluster to cluster. We find some significant variations. We go on to probe the projected shape as a function of projected cluster-centric radius. In both samples we find that on average galaxies have progressively rounder projected shapes at lower cluster-centric projected distance. In the SDSS sample we show that this trend exists above and beyond the trend for brighter galaxies to be more common near the centre of clusters (bright galaxies are on average rounder). In order to disentangle the trend for SRs (which are rounder) to be more common near the centre of clusters, we isolate a subsample of FRs only, by considering only galaxies with &epsilon; > 0.4. We find that even the intrinsically flat FRs are on average rounder at lower projected cluster-centric distance. We conclude that the observed trend is due either to the dynamic heating of the stellar discs being strongest near the centre of clusters, or due to an anti-correlation of the bulge fractions with the cluster-centric distance.

Dans le modèle standard de cosmologie ΛCDM, environ 72% de la densité d'énergie totale de l'Univers se présente sous la forme d'énergie sombre qui causerait la présente accélération de l'Univers. Parmi les sondes cosmologiques couramment utilisées, l'effet de lentille gravitationnel forte dans les amas est une technique prometteuse fournissant des contraintes orthogonales sur les paramètres cosmologiques. Le programme HFF a permis une amélioration significative de l'estimation de la distribution de masse des amas. Cependant, la modélisation de l'effet de lentille forte dans les amas semble ne pas atteindre la résolution angulaire des observations HST. Cette thèse fournit une meilleure compréhension de l'impact des erreurs systématiques dans la modélisation paramétrique de l'effet de lentille forte dans les amas de galaxies et, donc, sur la détermination des paramètres cosmologiques. Premièrement, j'ai analysé deux amas de galaxies simulés, ayant les mêmes caractéristiques que les amas du programme HFF, Ares et Hera. J'ai utilisé plusieurs estimateurs afin d'évaluer la qualité de nos reconstructions obtenues, permettant de quantifier l'impact des erreurs systématiques dues, au choix des profils de densité et configurations et, ensuite, de la disponibilité d'images multiples dans la détermination de paramètres cosmologiques. Deuxièmement, en utilisant deux amas de galaxies, j'ai testé quatre modèles cosmologiques pour lesquels l'équation d'état de l'énergie sombre, w(z), est paramétrisée en fonction du redshift. J'ai réalisé plusieurs modélisations pour quantifier l'impact des erreurs systématiques liées à la position des images multiples sur les paramètres cosmologiques. / In the standard cosmological model ΛCDM, about 70% of the energy density of the Universe is in the form of a dark energy that would cause the current acceleration of the Universe. Among the extensively used cosmological probes, using strong lensing features in galaxy clusters is a promising technique yielding orthogonal constraints on cosmological parameters. The program HFF has led to a significant improvement of cluster mass estimates. However, strong lensing modelling appears to be still unable to match the HST observations angular resolution.This thesis provides a better understanding of how systematic errors impact the retrieval of cosmological parameters in order to use strong lensing clusters as reliable cosmological probes. Firstly, I have analyzed two simulated HFF-like clusters, Ares and Hera, I use several estimators to assess the goodness of our reconstructions by comparing our multiple models, with the input models. This allows to quantify the impact of systematic errors arising from the choice of different density profiles and configurations and, secondly, from the availability of constraints in the parametric modelling of strong lensing clusters and therefore on the retrieval of cosmological parameters. Secondly, I probe four cosmological models in which the equation of state of dark energy, w(z), is parameterized as a function of redshift using strong lensing features in two galaxy clusters. To quantify how the cosmological constraints are biased due to systematic effects in the strong lensing modelling, I carry out several modelling attempts considering different uncertainties for the multiple images positions.

Les amas de galaxies sont des structures massives composées à plus de 80% de matière noire. Leur coeur peut atteindre une densité de masse critique qui en déformant l'espace-temps fait converger les rayons lumineux vers l'observateur. Grâce à des relevés photométriques profonds de l'amas Abell 2744, de nombreux systèmes multiples ont été découverts. Identifier ces systèmes reste un défi, j'ai donc développé une méthode robuste basée sur les propriétés photométriques conservées par l'effet de lentille gravitationnelle qui permet de les détecter automatiquement. Le meilleur moyen de prouver que des images proviennent de la même galaxie reste la mesure de leur distance(redshifts) grâce à leur spectre. En analysant les données collectées par le spectrographe à intégrale de champ MUSE j'ai mesuré un grand nombre de sources (514) dont 83 d'entre elles sont des images multiples. Bénéficiant de cette large couverture spectrale, j'ai créé un modèle paramétrique de masse parmi les plus contraints à ce jour. La sensibilité atteinte par le modèle permet de sonder l'influence de structures périphériques (jusqu'à une distance de 700kpc), révélant ainsi des erreurs systématiques sur la mesure de la masse due à la paramétrisation du modèle (6%). Comparé aux précédentes études, on voit une diminution de 10% de la masse dans un rayon 100 kpc montrant ainsi en partie le gain offert par la spectroscopie. Ce gain, bien que négligeable sur la mesure de l'amplification, s'est avéré pouvoir contraindre la balance en masse entre les différentes composantes de notre modèle, dépassant par endroits 2 fois l'incertitude statistique / Clusters of galaxies are large and massive structures containing more than 80% of dark matter. In the cluster core, the mass density can reach a critical threshold making the curvature of space-time large enough to bend light path and then allow multiple convergence of images from the same sources to appear on the observer field of view. Thanks to deep photometric coverage of Abell 2744, a lot of multiply-imaged systems were discovered. Nevertheless, finding them remain a challenge and based on the preserved photometric properties by lensing, I developed a robust method to automatically find them. However, measuring the redshifts for each multiple images remains the best way to surely associate them. The deep coverage of the integral field spectrograph MUSE allowed me to identify a large number of sources ( 514 ) among them 83 were multiple images. Thanks to this large spectroscopic coverage, I built one of the most constrained parametric mass model for lensing cluster to date. The sensitivity raised by this model allow me to probe the influence of outskirts substructures ( at 700 kpc distance ), revealing systematic sources of uncertainties related to the mass model parametrisation ( 6% ). Compared to previous studies, I notice a 10% lower mass in the center ( within 100kpc ) showing one of the benefit of large spectroscopic constraints. This benefit, is smaller on the amplification estimation but shows a significant discrepancy between different mass counterparts in the models, up to 2 times the statistical uncertainties

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-10-18T17:24:51Z No. of bitstreams: 1 LEONARDO RIBEIRO COLAÇO – DISSERTAÇÃO (PPGFísica) 2016.pdf: 3372949 bytes, checksum: 8387f15d435a4dd929618ecca701927e (MD5) / Made available in DSpace on 2018-10-18T17:24:51Z (GMT). No. of bitstreams: 1 LEONARDO RIBEIRO COLAÇO – DISSERTAÇÃO (PPGFísica) 2016.pdf: 3372949 bytes, checksum: 8387f15d435a4dd929618ecca701927e (MD5) Previous issue date: 2018 / Capes / As teorias cosmológicas mais comumente aceitas são baseadas no pressuposto de que as constantes fundamentais da natureza, como a constante gravitacional G, a constante de estrutura fina α, entre outras, são de fato constantes. Sendo assim, a suposição de que essas constantes não variam no espaço-tempo é apenas uma hipótese, precisando então ser comprovada a partir de dados experimentais. Neste trabalho, propomos um novo método, independente de modelo cosmológico, capaz de investigar uma possível variação como redshift da constante de estrutura fina, α=е2 /hc, onde é a carga elementar, h é a constante de Planck dividida por 2 π e c é a velocidade da luz. Para tal fim, mostramos também que a técnica combinada do Efeito Sunyaev-Zel'dovich (ESZ) como Brilho Superficial em raios-X (SX) para se medir Distância de Diâmetro Angular (DDA) dos Aglomerados de Galáxias (AG) é dependente da constante de estrutura fina. Mais precisamente,se = 0 (z), argumentamos que os dados atuais dessa técnica fornecem DobsA (z) = 2(z)DA(z), onde DA(z) é a verdadeira DDA para o aglomerado de galáxias e (z) é o campo escalar Dilaton que governa uma possível variação em α. Considerando uma amostra de 25 medidas de DobsA (z), feitas por De Filippis et al. (2005),via ESZ/SX na faixa de redshift 0; 023 < zAG < 0; 784 e estimando medidas de DA(z) do assim chamado Union 2.1 Compilation de Super nova e tipoIa (SNeIa), onde o redshift das SNeIa foram cuidadosamente selecionados para coincidir como redshift do aglomerado de galáxias associado com a maior diferença de redshift obedece a jzAG 􀀀 zSNej < 0; 005. Portanto, foi possível atribuir algumas restrições sobre uma possível variação de α para uma classe de Modelos Dilaton Run away, (z) =1􀀀 ln (1+ z). Nossas análises mostraram que = 􀀀0; 037 0; 157 em 1 , ou seja, nossas análises são compatíveis com uma não variação da constante de estrutura fina. / The most common accepted cosmological theories are base don the assumption that the fundamental constants of nature, suchas the gravitational constant G, the new structure constant α, and others, are infact constant. Thus, the assumption that these constants do not vary with time or space is only a hypothesis, then it needs to be confirmed from experimental data. In this paper, we propose a new method, independent of cosmological models, which is cap able to investigate a possible variation with redshift of the new structure constant, α = e2=hc, where e is the elementary charge, h is Planck's constant over 2π and c is the speed of light. For that purpose, we also show that the combined technique between Sunyaev-Zel'doviche effect (SZE) and X-ray surface brightness (SX) to measure Angular Diameter Distance (ADD) of Galaxy Clusters (GC), dependents on the new structure constant. More precisely, if α = α0 (z) we argue that the current data of this technique gives DobsA (z) = 2(z)DA(z), where DA(z) is the true ADD for galaxy clustersand (z) is the dilatons calareld that governs a possible variation of α. We considere da sample of 25 measurements of Dobs A (z), made by De Filipp is e tal. (2005),via ESZ/SX in the range of redshift 0:023 < zGC < 0:784 and we also estimated DA(z) from the so-called Union 2.1 Super novaeIa(SNEIa) Compilation,where the SNeIa redshifts were carefully selected to match the one soft he as sociated galaxy cluster with the larger redshiftd iαe rencefollows jzGC 􀀀� zSNej < 0:005. There for e,it was possible to put some constraints on a possible variation of α for a class of Dilaton Run a way Model, (z) =1 􀀀� ln (1+ z). We obtained = 􀀀�0; 037 0; 157 in1 , i.e.,our analysis is compatible with an on variation of the new structure constant.

No description available.

Les amas des galaxies sont l’une des plus grandes structures liées gravitationnellement de l’univers. Leur dynamique est complexe et bien que plusieurs études multi-longueur d’onde ont été effectuées depuis la fin du 20ème siècle, il persiste plusieurs incertitudes sur les subtilités de leur dynamique. À ce jour, le consensus scientifique est que les trous noirs supermassifs actifs au centre des amas ont un impact important sur l’évolution de ces structures. Le trou noir central agit comme centre gravitationnel, mais lorsque ce trou noir est actif, son rôle ne se limite pas seulement à son impact gravitationnel. D’une part, les trous noirs actifs ont un rôle crucial dans l’émission thermique des amas. En effet, les jets radio influencent l’émission rayons-X des amas en poussant mécaniquement le milieu intra-amas qui émet en rayons-X via l’émission Bremsstrahlung. Ce phénomène engendre la formation de cavités rayons-X qui constituent une preuve de la rétroaction énergétique du trou noir sur l’ensemble de l’amas. Un tel phénomène est nécessaire afin d’expliquer les résultats observationnels qui témoignent d’un refroidissement moins important que prédit théoriquement au centre des amas à cœur froid. D’autre part, il existe de plus en plus d’études qui supportent l’hypothèse que les trous noirs actifs ont un rôle dans la (ré-)accélération de particules relativistes responsables de l’émission synchrotron au cœur des amas à cœur froid. Ces structures appelées mini-halos sont typiquement diffuses en radio et donc difficiles à détecter. Dans ce mémoire, nous étudierons en détail l’émission radio de l’amas de galaxies massif à cœur froid MS 0735.6+7421 (z = 0.216). Cet amas est unique puisqu’il possède les jets radio les plus énergétiques détectés au centre d’un amas à cœur froid. Il s’agit donc d’un exemple de trou noir actif parmi les plus extrêmes connus. Cet objet constitue ainsi une cible parfaite afin d’étudier le lien qui unit la rétroaction du trou noir actif central et l’émission synchrotron au centre des amas à cœur froid. Pour réaliser cette étude, nous avons effectué une analyse radio exhaustive de MS 0735.6+7421 à l’aide de données acquises sur le Karl G. Jansky Very Large Array. Cette analyse a permis de détecter une nouvelle structure radio diffuse jamais détectée auparavant. Cette nouvelle structure possède une puissance radio à 1.4 GHz qui concorde avec celles des mini-halos les plus lumineux. Le résultat principal de notre étude supporte donc l’hypothèse selon laquelle il existe un lien fondamental entre la rétroaction du trou noir actif central et la formation de mini-halos au centre des amas à cœur froid. / Galaxy clusters are one of the largest gravitationally bound structures in the universe. They exhibit complex dynamics and even though several multi-wavelength studies have been conducted since the end of the 20th century, there are still a lot of uncertainties concerning their evolution. To this day, the scientific consensus is that the active supermassive black hole at the center of the cluster has a profound impact on the cluster’s evolution. Indeed, the central supermassive black hole has a substantial gravitational impact, but when the black hole actively accretes material, its role goes beyond its gravitational influence. Active supermassive black holes have a crucial role in terms of the thermal emission in clusters. Indeed, the radio jets influence the X-ray emission of clusters by mechanically pushing the intracluster medium which emits in X-ray via Bremsstrahlung emission. This leads to the formation of X-ray cavities which are proof of the energetic feedback of the central supermassive black hole on the cluster. Such a phenomenon is required to reconcile the observational results that report less cooling at the center of cool core clusters than what is theoretically predicted. Moreover, there are more and more studies that support the hypothesis that active supermassive black holes have a crucial role in the (re-)acceleration of seed particles responsible for synchrotron emission at the center of cool core clusters. These structures are named mini-halos and are usually difficult to detect because they are diffuse. In this Master’s thesis, we will study the radio emission of the massive cool core galaxy cluster MS 0735.6+7421 (z = 0.216). This cluster is unique because it exhibits the most powerful radio jets ever detected at the center of a cool core cluster. It thus contains one of the most powerful active supermassive black holes known. This object is a perfect target to study the link between active black hole feedback and synchrotron emission in cool core clusters. To conduct this study, we performed a radio analysis of MS 0735.6+7421 with new data obtained with the Karl G. Jansky Very Large Array. This analysis led to the discovery of an extended diffuse radio structure. This newly detected structure has a radio power at 1.4 GHz that matches the most luminous mini-halos known in the literature. The principal result of our study argues in favor of the hypothesis that there is a fundamental link between active black hole feedback and the formation of mini-halos at the center of cool core clusters.