Search

Galaxies live in very different types of environment. Those different environments are relics from the evolution of the Universe since the Big Bang. This network of structures observed via large scale surveys is called Cosmic Web. Within this web, galaxies can be isolated, in a filament, in a group, or in a cluster. When part of a cluster of galaxies, their morphologies, gas content (cold and hot), and star formation activities is seen to be affected by other galaxies, or by the gas inside the cluster. However, the long-term effects of the local environment on galaxy evolution remain unclear. Also, it has been observed that a pre-processing is happening long before the galaxies enter the cluster cores, which could explain the build-up of the passive galaxy sequence, where galaxies have quenched star formation. The aim of this thesis is to see if and how the cold molecular gas reservoir of galaxies is modified when star formation activity is decreasing and if there is a link with the position of the galaxy in the CW around the cluster. We gathered unprecedented observations: the first and largest survey of the molecular gas content of galaxies in and around the same cluster environment at intermediate redshifts. These Atacama Large Millimeter Array observations are part of a larger survey called Spatially Extended ESO Distant Cluster Survey. We are focusing on two clusters at a redshift of 0.5, which benefit from previous deep photometric and spectroscopic observations. This will allow us to derive accurate stellar masses and star formation rates, in order to compare those galaxies to other surveys of the cold gas content of galaxies, either in the field or inside different clusters. We unveiled a new population of galaxies with normal star formation rates but less cold molecular gas than other galaxies at the same stellar mass. This could be an indication that the gas reservoir responsible for the star formation changes either in mass or properties, before the star formation is affected. We also noticed that galaxies with the lowest cold-molecular-gas-to-stellar-mass ratios are preferentially either in the cluster core or in overdensities away from the cluster, confirming the existence of a pre-processing in overdensities surrounding the cluster. But active galaxies inside or close to the cluster, do not always have depleted CO reservoir. This thesis opens up new prospects on the study of the cold gas content of galaxies at intermediate redshift. It showed the necessity to observe galaxies that are in a transition regime between star forming and passive, in order to understand how star formation is suppressed around clusters. Those results could be extended to much larger samples, with the help of the upcoming new generation of instruments such as the Square Kilometer Array.

Galaxies form and evolve in different environments, shaped by the distribution of dark matter halos. The evolution of galaxies in low-density environments significantly differs from those in dense structures, where environmental drivers reduce the gas content quenching their star formation capacity earlier than their isolated counterparts. The goal of this work is to study the TFR for galaxies at intermediate z groups. This relation provides key information on the dynamical support, and on formation and evolutionary state of galaxies. The advent of powerful IFS instruments like MUSE, allows to perform spatially resolved studies at intermediate redshifts (z). This research is based on the exploitation of an unique sample of 12 dense galaxy groups selected in the COSMOS field, from the GTO MUSE gAlaxy Groups In Cosmos (MAGIC) Survey, at 0.3 < z < 0.8. The kinematics was extracted using the [OII] λλ3726,3729 Å doublet. A bulge-disk decomposition and a 2D kinematic modeling were applied to recover the maximum rotation velocity at 2.2 disk scale lengths (R_2.2), the intrinsic velocity dispersion (σ) and the dynamical mass. I performed a rigorous sample selection in setting limits on the spatial resolution and on the signal-to-noise ratio (SNR). I compared my results with previous studies in different environments finding our method reduces the outliers in the TFR. I found the stellar and baryonic mass fractions increase with stellar mass. I also found a clear offset of the TFR zero-point between different environments implying that at fixed stellar mass, galaxies in dense environments rotate faster than in low-density environments. The evolution of the TFR in dense environments could be due to a combination of quenching of star formation and contraction of the baryonic content., Las galaxias se forman y evolucionan en entornos diferentes, moldeados por la distribución de los halos de materia oscura. La evolución de las galaxias en entornos de baja densidad difiere significativamente de las que se encuentran en estructuras densas, donde los factores ambientales reducen el contenido de gas disminuyendo su capacidad de formación estelar antes que sus homólogas aisladas. El objetivo de este trabajo es estudiar la Relación Tully Fisher (RTF) para galaxias en grupos a corrimientos al rojo (z) intermedios. Esta relación proporciona información clave sobre el soporte dinámico y el estado de formación y evolución de las galaxias. La llegada de potentes espectrógrafos de campo integral (IFS) como MUSE, permite realizar estudios espacialmente resueltos a z intermedios. Esta investigación se basa en la explotación de una muestra única de 12 grupos densos de galaxias densas seleccionadas en el campo COSMOS, procedentes del GTO MUSE gAlaxy Groups In Cosmos (MAGIC) Survey, a 0.3 < z < 0.8. La cinemática se extrajo utilizando el doblete [OII] λλ3726,3729 Å. Se aplicó una descomposición bulbo-disco y un modelado cinemático 2D para recuperar la velocidad máxima de rotación a 2,2 radios de escala del disco (R_2,2), la dispersión de velocidad intrínseca (σ) y la masa dinámica. Llevé a cabo una rigurosa selección de la muestra al establecer los límites para la resolución espacial y la relación señal a ruido (SNR). Comparé mis resultados con estudios anteriores en diferentes entornos encontrando que nuestro método reduce los valores atípicos en la RTF. Encontré que las fracciones de masa estelar y bariónica aumentan con la masa estelar. También se observa un claro desplazamiento del punto cero de la RTF en diferentes ambientes, lo que implica que a una masa estelar fija, las galaxias en entornos densos giran más rápido que en entornos de baja densidad. La evolución de la RTF en entornos densos podría deberse a una combinación de apagado de la formación estelar y contracción del contenido bariónico., Les galaxies se forment et évoluent dans différents environnements, façonnées par la distribution des halos de matière noire. L'évolution des galaxies dans les environnements à faible densité (EFD) diffère considérablement de celles des structures denses (SD), où les facteurs environnementaux réduisent la teneur en gaz en éteignant leur capacité de formation stellaire plus tôt que leurs homologues isolées. Le but de ce travail est d'étudier la Relation Tully Fisher (RTF) des galaxies en groupes à décalages spectraux vers le rouge (z) intermédiaires. Cette relation fournit des informations clés sur le support dynamique, ainsi que sur la formation et l'état évolutif des galaxies. L'avènement des spectrographes à champ intégral (IFS) comme MUSE, permet d'effectuer des études spatialement résolues à z intermédiaires. Cette recherche est basée sur l'exploitation d'un échantillon unique de 12 groupes de galaxies sélectionnés du sondage GTO MUSE gAlaxy Groups In Cosmos (MAGIC), à 0,3 < z < 0,8. La cinématique a été extraite à l'aide du doublet [OII] λλ3726,3729 Å . Une décomposition bulbe-disque et une modélisation cinématique 2D ont été appliquées pour récupérer la vitesse de rotation maximale à 2.2 fois la longueur de l'échelle du disque (R_2.2), la dispersion des vitesses (σ) intrinsèque et la masse dynamique. J'ai effectué une sélection d'échantillons en fixant des limites sur la résolution spatiale et sur le rapport signal sur bruit (S/B), notre méthode réduit le nombre de galaxies dominées par σ. J'ai trouvé que les fractions de masse stellaire et baryonique augmentent avec la masse stellaire, et un décalage du point zéro (z_0) de la RTF entre différents environnements qui implique que les galaxies dans des structures denses tournent plus vite que dans des environnements à faible densité. L'évolution du RTF en milieu dense pourrait être due à une combinaison d'extinction de la formation stellaire et la contraction du contenu baryonique.

Galaxies form and evolve in different environments, shaped by the distribution of dark matter halos. The evolution of galaxies in low-density environments significantly differs from those in dense structures, where environmental drivers reduce the gas content quenching their star formation capacity earlier than their isolated counterparts. The goal of this work is to study the TFR for galaxies at intermediate z groups. This relation provides key information on the dynamical support, and on formation and evolutionary state of galaxies. The advent of powerful IFS instruments like MUSE, allows to perform spatially resolved studies at intermediate redshifts (z). This research is based on the exploitation of an unique sample of 12 dense galaxy groups selected in the COSMOS field, from the GTO MUSE gAlaxy Groups In Cosmos (MAGIC) Survey, at 0.3 < z < 0.8. The kinematics was extracted using the [OII] λλ3726,3729 Å doublet. A bulge-disk decomposition and a 2D kinematic modeling were applied to recover the maximum rotation velocity at 2.2 disk scale lengths (R_2.2), the intrinsic velocity dispersion (σ) and the dynamical mass. I performed a rigorous sample selection in setting limits on the spatial resolution and on the signal-to-noise ratio (SNR). I compared my results with previous studies in different environments finding our method reduces the outliers in the TFR. I found the stellar and baryonic mass fractions increase with stellar mass. I also found a clear offset of the TFR zero-point between different environments implying that at fixed stellar mass, galaxies in dense environments rotate faster than in low-density environments. The evolution of the TFR in dense environments could be due to a combination of quenching of star formation and contraction of the baryonic content.; Las galaxias se forman y evolucionan en entornos diferentes, moldeados por la distribución de los halos de materia oscura. La evolución de las galaxias en entornos de baja densidad difiere significativamente de las que se encuentran en estructuras densas, donde los factores ambientales reducen el contenido de gas disminuyendo su capacidad de formación estelar antes que sus homólogas aisladas. El objetivo de este trabajo es estudiar la Relación Tully Fisher (RTF) para galaxias en grupos a corrimientos al rojo (z) intermedios. Esta relación proporciona información clave sobre el soporte dinámico y el estado de formación y evolución de las galaxias. La llegada de potentes espectrógrafos de campo integral (IFS) como MUSE, permite realizar estudios espacialmente resueltos a z intermedios. Esta investigación se basa en la explotación de una muestra única de 12 grupos densos de galaxias densas seleccionadas en el campo COSMOS, procedentes del GTO MUSE gAlaxy Groups In Cosmos (MAGIC) Survey, a 0.3 < z < 0.8. La cinemática se extrajo utilizando el doblete [OII] λλ3726,3729 Å. Se aplicó una descomposición bulbo-disco y un modelado cinemático 2D para recuperar la velocidad máxima de rotación a 2,2 radios de escala del disco (R_2,2), la dispersión de velocidad intrínseca (σ) y la masa dinámica. Llevé a cabo una rigurosa selección de la muestra al establecer los límites para la resolución espacial y la relación señal a ruido (SNR). Comparé mis resultados con estudios anteriores en diferentes entornos encontrando que nuestro método reduce los valores atípicos en la RTF. Encontré que las fracciones de masa estelar y bariónica aumentan con la masa estelar. También se observa un claro desplazamiento del punto cero de la RTF en diferentes ambientes, lo que implica que a una masa estelar fija, las galaxias en entornos densos giran más rápido que en entornos de baja densidad. La evolución de la RTF en entornos densos podría deberse a una combinación de apagado de la formación estelar y contracción del contenido bariónico.; Les galaxies se forment et évoluent dans différents environnements, façonnées par la distribution des halos de matière noire. L'évolution des galaxies dans les environnements à faible densité (EFD) diffère considérablement de celles des structures denses (SD), où les facteurs environnementaux réduisent la teneur en gaz en éteignant leur capacité de formation stellaire plus tôt que leurs homologues isolées. Le but de ce travail est d'étudier la Relation Tully Fisher (RTF) des galaxies en groupes à décalages spectraux vers le rouge (z) intermédiaires. Cette relation fournit des informations clés sur le support dynamique, ainsi que sur la formation et l'état évolutif des galaxies. L'avènement des spectrographes à champ intégral (IFS) comme MUSE, permet d'effectuer des études spatialement résolues à z intermédiaires. Cette recherche est basée sur l'exploitation d'un échantillon unique de 12 groupes de galaxies sélectionnés du sondage GTO MUSE gAlaxy Groups In Cosmos (MAGIC), à 0,3 < z < 0,8. La cinématique a été extraite à l'aide du doublet [OII] λλ3726,3729 Å . Une décomposition bulbe-disque et une modélisation cinématique 2D ont été appliquées pour récupérer la vitesse de rotation maximale à 2.2 fois la longueur de l'échelle du disque (R_2.2), la dispersion des vitesses (σ) intrinsèque et la masse dynamique. J'ai effectué une sélection d'échantillons en fixant des limites sur la résolution spatiale et sur le rapport signal sur bruit (S/B), notre méthode réduit le nombre de galaxies dominées par σ. J'ai trouvé que les fractions de masse stellaire et baryonique augmentent avec la masse stellaire, et un décalage du point zéro (z_0) de la RTF entre différents environnements qui implique que les galaxies dans des structures denses tournent plus vite que dans des environnements à faible densité. L'évolution du RTF en milieu dense pourrait être due à une combinaison d'extinction de la formation stellaire et la contraction du contenu baryonique.

We study the star formation histories (SFHs) and mass-weighted ages of 331 UVJ-selected quiescent galaxies in 11 galaxy clusters and in the field at 11 has been driven by different physical processes than those at play at z=0., Comment: accepted Sept 7 2020, MNRAS

Theory predicts that galaxies are not randomly distributed in the Universe. They form a complex network of filamentary structures, the Cosmic Web, divided in clusters, groups, filaments and walls. This picture has been confirmed by the large galaxy redshift surveys. Galaxy properties like morphology and star formation rates are strongly influenced by their environment. The most radical transformations are observed in galaxy clusters, located at the intersection of filaments. Nevertheless, the location where the environment starts to play a role and the main physical phenomenon responsible for these changes are still unknown. The aim of this thesis is to determine where and how galaxies are affected by the environment, at local and global scales. We gathered high quality photometry in the 5 optical bands $u$, $g$, $r$, $i$ and $z$ with MegaCam on the Canada-France-Hawaii Telescope for 3 medium mass galaxy clusters at intermediate redshift, with a spatial extent on the sky plane reaching 8 to 13 times the cluster virial radii. These clusters were selected to represent as much as possible progenitors of clusters in the local Universe. The core of these clusters have rich ancillary data from the ESO Distant Cluster Survey. The redshift and mass ranges of these clusters, combined to the wide field of the observations make this study unique. We computed photometric redshifts to map the galaxy distribution around the clusters. We were able to identify overdense regions forming groups and filaments, unveiling for the first time the large scale structures in such details for this type of clusters. We studied the fraction of galaxies in the red sequence in different environments, namely in the field, filaments and groups. We find that significant quenching processes are already at work in filaments, even at large cluster-centric distances. We also show that the local neighborhood of galaxies has a stronger impact on galaxy colors than the global environment. An optical spectroscopic follow-up with the VIsible MultiObject Spectrograph on the Very Large Telescope confirms our photometric results. In particular, the fraction of galaxies with detected \otwo emission line is smaller with increasing density. We also find that the star formation rate, determined from [OII], is in average weaker in groups and clusters than in lower density environments. This thesis opens new perspectives to study the way galaxies populate the Cosmic Web. Combined to weak-lensing analysis and cosmological simulations, it will allow a deeper understanding of the structure formation and their baryonic content. It is a first step before extending the results to much larger samples, with the help of the upcoming all-sky cosmological surveys such as Euclid or the Square Kilometer Array.

We present the modeling of SINFONI integral field dynamics of 18 star forming galaxies at z ~ 2 from Halpha line emission. The galaxies are selected from the larger sample of the SINS survey, based on the prominence of ordered rotational motions with respect to more complex merger induced dynamics. The quality of the data allows us to carefully select systems with kinematics dominated by rotation, and to model the gas dynamics across the whole galaxy using suitable exponential disk models. We obtain a good correlation between the dynamical mass and the stellar mass, finding that large gas fractions Mgas~M*) are required to explain the difference between the two quantities. We use the derived stellar mass and maximum rotational velocity Vmax from the modeling to construct for the first time the stellar mass Tully-Fisher relation at z ~ 2.2. The relation obtained shows a slope similar to what is observed at lower redshift, but we detect an evolution of the zero point. We find that at z ~ 2.2 there is an offset in log(M*) for a given rotational velocity of 0.41+-0.11 with respect to the local Universe. This result is consistent with the predictions of the latest N-body/hydrodynamical simulations of disk formation and evolution, which invoke gas accretion onto the forming disk in filaments and cooling flows. This scenario is in agreement with other dynamical evidence from SINS, where gas accretion from the halo is required to reproduce the observed properties of a large fraction of the z ~ 2 galaxies., Comment: 10 pages, 6 figures, submitted to ApJ