Cosmological constraints from galaxy clusters rely on accurate measurements of the mass and internal structure of clusters. An important source of systematic uncertainty in cluster mass and structure measurements is the secure selection of background galaxies that are gravitationally lensed by clusters. This issue has been shown to be particular severe for faint blue galaxies. We therefore explore the selection of faint blue background galaxies, by reference to photometric redshift catalogues derived from the Cosmological Evolution Survey (COSMOS) and our own observations of massive galaxy clusters at z similar or equal to 0.2. We show that methods relying on photometric redshifts of galaxies in/behind clusters based on observations through five filters, and on deep 30-band COSMOS photometric redshifts are both inadequate to identify safely faint blue background galaxies with the same 1 per cent contamination level that we have achieved with red galaxies. This is due to the small number of filters used by the former, and absence of massive galaxy clusters at redshifts of interest in the latter. Nevertheless, our least contaminated blue galaxy sample yields stacked weak-lensing results consistent with our previously published results based on red galaxies, and we show that the stacked clustercentric number density profile of these faint blue galaxies is consistent with expectations from consideration of the lens magnification signal of the clusters. Indeed, the observed number density of blue background galaxies changes by similar to 10-30 per cent across the radial range over which other surveys assume it to be flat.

As galáxias espirais continuam desafiando as teorias que buscam explicar como o universo se tornou o que observamos hoje. Em especial, no contexto hierárquico de formação de estruturas, é difícil entender como as galáxias podem ser tão parecidas entre si, obedecendo a relações de escala tão estritas, apesar de suas diferentes histórias evolutivas. A fim de esclarecer algumas dessas perguntas, o projeto GHASP observou 203 galáxias na linha H-alfa, através de interferometria Fabry-Perot, construindo uma base de dados homogênea e de alta qualidade para estudos cinemáticos do universo local. Neste trabalho, buscamos complementar os resultados consolidados do GHASP, apresentando um estudo fotométrico para 173 destas galáxias na banda Rc. Os dados, provenientes de observações no telescópio de 1,2m do Observatório de Haute-Provence ou do projeto SDSS, foram cuidadosamente tratados com ferramentas de redução IRAF adaptados para a automação dos processos. Através do ajuste de elipses sobre as galáxias, foram obtidos perfis de brilho calibrados e magnitudes totais para as galáxias da amostra. A decomposição da luz destes perfis foi estudada através de um modelo exponencial para o disco e uma função de Sérsic para o bojo. Os resultados da decomposição bojo-disco foram utilizados para o estudo de relações de escala e correlações entre os diversos parâmetros medidos. Algumas das mais significativas correlações são detalhadas, como a relação entre os parâmetros de escala de bojo e disco, que reforçam o cenário de evolução secular das galáxias disco. Finalmente, com o auxílio dos resultados cinemáticos da literatura, apresentamos, pela primeira vez, a relação Tully-Fisher para a amostra do GHASP, na banda Rc. / The spiral galaxies still challenge the theories that try to explain how the universe has turned into what we see today. In particular, in the context of the hierarchical structure formation, it is difficult to understand how galaxies can be so similar, obeying such strict scaling relations, in spite of their distinct evolutionary histories. In order to clarify some of these questions, the GHASP project has observed 203 galaxies in the H-alpha line, through Fabry-Perot interferometry, and has built a homogeneous and high quality database for kinematical studies in the local universe. In the present work, we seek to supplement the GHASP project results, presenting a photometric study for 173 of those galaxies in the Rc band. The data, taken with the 1.2m telescope at Haute-Provence Observatory or extracted from the SDSS database, was carefully treated with customized IRAF routines for the automation of most of the jobs. By fitting ellipses over the galaxies, calibrated surface brightness profiles and total magnitudes were obtained for galaxies in the sample. Then, galaxy light decomposition techniques were employed using an exponential model for the disk and a Sérsic function for the bulge. The results of the bulge-disk decomposition were used for the study of scaling relations and correlations among the several measured parameters. A few of the most significant correlations were described, such as the relation between bulge and disc scale lengths, reinforcing the galaxy-disk secular evolutionary scenario. Finally, with the aid of kinematic results from the literature, we present, for the first time, the Tully-Fisher relation for the GHASP sample, in the Rc-band.

As galáxias espirais continuam desafiando as teorias que buscam explicar como o universo se tornou o que observamos hoje. Em especial, no contexto hierárquico de formação de estruturas, é difícil entender como as galáxias podem ser tão parecidas entre si, obedecendo a relações de escala tão estritas, apesar de suas diferentes histórias evolutivas. A fim de esclarecer algumas dessas perguntas, o projeto GHASP observou 203 galáxias na linha H-alfa, através de interferometria Fabry-Perot, construindo uma base de dados homogênea e de alta qualidade para estudos cinemáticos do universo local. Neste trabalho, buscamos complementar os resultados consolidados do GHASP, apresentando um estudo fotométrico para 173 destas galáxias na banda Rc. Os dados, provenientes de observações no telescópio de 1,2m do Observatório de Haute-Provence ou do projeto SDSS, foram cuidadosamente tratados com ferramentas de redução IRAF adaptados para a automação dos processos. Através do ajuste de elipses sobre as galáxias, foram obtidos perfis de brilho calibrados e magnitudes totais para as galáxias da amostra. A decomposição da luz destes perfis foi estudada através de um modelo exponencial para o disco e uma função de Sérsic para o bojo. Os resultados da decomposição bojo-disco foram utilizados para o estudo de relações de escala e correlações entre os diversos parâmetros medidos. Algumas das mais significativas correlações são detalhadas, como a relação entre os parâmetros de escala de bojo e disco, que reforçam o cenário de evolução secular das galáxias disco. Finalmente, com o auxílio dos resultados cinemáticos da literatura, apresentamos, pela primeira vez, a relação Tully-Fisher para a amostra do GHASP, na banda Rc. / The spiral galaxies still challenge the theories that try to explain how the universe has turned into what we see today. In particular, in the context of the hierarchical structure formation, it is difficult to understand how galaxies can be so similar, obeying such strict scaling relations, in spite of their distinct evolutionary histories. In order to clarify some of these questions, the GHASP project has observed 203 galaxies in the H-alpha line, through Fabry-Perot interferometry, and has built a homogeneous and high quality database for kinematical studies in the local universe. In the present work, we seek to supplement the GHASP project results, presenting a photometric study for 173 of those galaxies in the Rc band. The data, taken with the 1.2m telescope at Haute-Provence Observatory or extracted from the SDSS database, was carefully treated with customized IRAF routines for the automation of most of the jobs. By fitting ellipses over the galaxies, calibrated surface brightness profiles and total magnitudes were obtained for galaxies in the sample. Then, galaxy light decomposition techniques were employed using an exponential model for the disk and a Sérsic function for the bulge. The results of the bulge-disk decomposition were used for the study of scaling relations and correlations among the several measured parameters. A few of the most significant correlations were described, such as the relation between bulge and disc scale lengths, reinforcing the galaxy-disk secular evolutionary scenario. Finally, with the aid of kinematic results from the literature, we present, for the first time, the Tully-Fisher relation for the GHASP sample, in the Rc-band.

We present new spatially resolved surface photometry in the far-ultraviolet (FUV) and near-ultraviolet (NUV) from images obtained by the Galaxy Evolution Explorer (GALEX) and IRAC1 (3.6 mu m) photometry from the Spitzer Survey of Stellar Structure in Galaxies (S(4)G). We analyze the radial surface brightness profiles mu(FUV), mu(NUV), and mu[3.6], as well as the radial profiles of (FUV - NUV), (NUV -[3.6]), and (FUV -[3.6]) colors in 1931 nearby galaxies (z < 0.01). The analysis of the 3.6 mu m surface brightness profiles also allows us to separate the bulge and disk components in a quasi-automatic way and to compare their light and color distribution with those predicted by the chemo-spectrophotometric models for the evolution of galaxy disks of Boissier & Prantzos. The exponential disk component is best isolated by setting an inner radial cutoff and an upper surface brightness limit in stellar mass surface density. The best-fitting models to the measured scale length and central surface brightness values yield distributions of spin and circular velocity within a factor of two of those obtained via direct kinematic measurements. We find that at a surface brightness fainter than mu([3.6]) = 20.89 mag arcsec(-2), or below 3 x 10(8) M-circle dot kpc(-2) in stellar mass surface density, the average specific star formation rate (sSFR) for star-forming and quiescent galaxies remains relatively flat with radius. However, a large fraction of GALEX Green Valley galaxies show a radial decrease in sSFR. This behavior suggests that an outside-in damping mechanism, possibly related to environmental effects, could be testimony of an early evolution of galaxies from the blue sequence of star-forming galaxies toward the red sequence of quiescent galaxies.

We have identified 1027 star-forming complexes in a sample of 46 galaxies from the Spirals, Bridges, and Tails (SB&T) sample of interacting galaxies, and 693 star-forming complexes in a sample of 38 non-interacting spiral (NIS) galaxies in 8 μm observations from the Spitzer Infrared Array Camera. We have used archival multi-wavelength UV-to IR observations to fit the observed spectral energy distribution of our clumps with the Code Investigating GALaxy Emission using a double exponentially declined star formation history. We derive the star formation rates (SFRs), stellar masses, ages and fractions of the most recent burst, dust attenuation, and fractional emission due to an active galactic nucleus for these clumps. The resolved star formation main sequence holds on 2.5 kpc scales, although it does not hold on 1 kpc scales. We analyzed the relation between SFR, stellar mass, and age of the recent burst in the SB&T and NIS samples, and we found that the SFR per stellar mass is higher in the SB&T galaxies, and the clumps are younger in the galaxy pairs. We analyzed the SFR radial profile and found that the SFR is enhanced through the disk and in the tidal features relative to normal spirals.

Over recent years there has been an increase of the number of secure supermassive black hole (SMBH) detections. These SMBH measurements have lead astronomers to establish well defined empirical relationships between the SMBH mass and some of the properties of the host galaxy. The number of galaxies with SMBH mass measurements is currently limited to about 100. One approach of expanding the study of the SMBH is to use the empirical relations for estimating M[subscript(bh)] for larger samples of galaxies. The investigation of the SMBH population (or SMBH mass function) for large sample of galaxies in the nearby universe has helped to constrain the SMBH and the galaxy evolution. Previous estimates of the SMBH mass function at low redshift were produced mainly by combining the measurements of the galaxy luminosity or velocity function with one of the SMBH scaling relations. In the first part of the thesis I will present an independent construction of the nearby supermassive black hole mass function by applying the optical M[subscript(bh)]–L relation onto the Millennium Galaxy Catalogue (MGC). Additionally, in the second part I will provide photometric analysis of all UKIDSS galaxies for which SMBH masses have been measured. I will derive composite profiles of brightness, ellipticity and position angles of each galaxy. I will show that the Sérsic function fits the brightness profile of the majority of the elliptical galaxies and the bulge of disk galaxies and I will provide alternative multi-component fits when necessary. Then these photometric parameters will be used for constructing the M[subscript(bh)]–L relation in the near-IR and to investigate the M[subscript(bh)]–n relation. In the third part I will construct the near-IR SMBH mass function for the Galaxy and Mass Assembly (GAMA) survey. For this purpose I will apply the newly derived M[subscript(bh)]–L relation onto an elliptical subsample of K-band images. The advantage of this SMBH mass function is that during the M[subscript(bh)]–L construction I used the same quality images and techniques used on the GAMA survey. Apart from the M[subscript(bh)]–L relation, the M[subscript(bh)]–sigma relation was used as an alternative approach for a subsample of galaxies for which the velocity dispersions were available. Furthermore, I employed both local SMBH mass functions (MGC & GAMA) for estimating the SMBH mass density at redshift zero and accounted for the dependence of the total SMBH density on the look-back time by comparing with semi-analytic SMBH mass functions. Finally, from the SMBH mass density I estimated the baryon fraction that is locked into SMBHs.

Galaxy clusters are the largest gravitationally bound structures in the Universe. Their masses are dominated by dark matter ($\sim$85\% of the mass) with stars representing 1-4\% of their masses. A hot, X-ray emitting gas called the intracluster medium makes most of their baryonic mass. The presence of this gas and of numerous neighbouring galaxies prematurely stop the star formation in clusters. In other terms, more galaxies in clusters are passive than in the general population of galaxies. This effect is mass and position-dependant: high-mass galaxies are more likely to be passive than less massive ones; galaxies inhabiting the cluster core are also less likely to form stars than those in the outskirts. The fraction of passive galaxies is greater in local clusters than in high-redshift ones, because they had more time to evolve. Much is unknown about the cessation of star formation, called quenching, in clusters. Thus, although many examples of infalling galaxies being stripped of their gas have been reported for low-mass galaxies, it is unclear if the most massive members became quenched before or after they become cluster members. The relationship between quenching and the cluster mass is also poorly understood. Despite the variety of methods devised to find clusters of galaxies, most of what we know about quenching in $z\gtrsim 1$ clusters was discovered with optically/infrared-selected cluster samples (clusters found as overdensities of galaxies), or samples of mixed origin. Yet, there is tentative evidence that optically/infrared-selected samples are biased toward having more passive galaxies than those that were X-ray selected. In the present dissertation, quenching is explored in X-ray selected cluster samples. A sample of high-redshift, low-mass galaxy clusters is built by finding galaxy overdensities coincident with sources of extended X-ray emission. A photometry-based analysis reveals that the fraction of quenched galaxies in these clusters is very variable. Moreover, the brightest cluster galaxies are also diverse. Yet, for all the information that photometry can provide, this sample candidate clusters need to be confirmed with spectroscopy. Spectroscopic observations obtained for four candidate clusters are reduced and analysed. The results show that three of them are clusters, the fourth candidate being a superposition of structures. Member spectra are examined to infer their star formation history, and the results shows the existence of an intermediary population of galaxies, where an old stellar population coexists with weak star formation. Finally, the galaxies of a $z=1.98$ X-ray selected cluster, XLSSC 122 are investigated in detail. Photometric data in 12 bands are organized to perform spectral energy distribution fittings, a technique that allows a simplified reconstitution of the history of the star formation. Results show that the members were formed at diverse epochs, the oldest being about 2.5 Gyrs old. Simulations drawn from the Multi Dark Planck 2 are used to infer the mass-scale of the cluster when the oldest galaxies were formed, something that has never been done before. The oldest galaxies were probably formed when XLSSC 122 had accreted $<$10\% of its $z=1.98$ mass, i.e. the mass-scale of a galaxy group. / Graduate

Alors que les galaxies évoluent, leur milieu interstellaire (MIS) s’enrichit continuellement en métaux, et cet enrichissement influence la formation d’étoiles. Les galaxies naines de faible métallicité de l’Univers Local sont les candidates idéales pour étudier l’influence de cet enrichissement en métaux sur les propriétés du MIS des galaxies et nous donne un aperçu des processus d’enrichissement et de formation stellaire dans des conditions proches de celles trouvées dans les systèmes pauvres en métaux de l’Univers primordial. Des études précédentes ont montré que le MIS des galaxies naines pose un certain nombre d’énigmes en terme d’abondance des grains, de composition de la poussière et même des processus d’émission en infrarouge lointain (FIR). Cependant, ces études étaient limitées à la poussière chaude émettant à des longueurs d’onde plus courtes que 200 micromètres et étaient effectuées sur un petit nombre de galaxies. Grâce à une sensibilité et une résolution améliorées dans les domaines FIR et submillimétriques (submm), Herschel nous donne une vue nouvelle sur les propriétés de la poussière froide dans les galaxies et nous permet d’étudier les galaxies les plus pauvres en métaux de manière systématique. Dans ce travail, je mène une étude des propriétés des poussières dans les galaxies naines et compare avec des environnements plus riches en métaux, pour aborder la question de l’impact de la métallicité sur les propriétés de la poussière. La nouveauté de ce travail réside dans le fait que les galaxies naines sont étudiées de manière systématique, nous permettant d’accéder aux, et de quantifier les propriétés générales représentatives de ces systèmes. Cette étude est conduite sur toute la gamme de longueurs d’onde infrarouge (IR)-submm, avec les nouvelles observations en FIR/submm d’Herschel, ainsi que des données Spitzer, WISE, IRAS, et 2MASS. Nous complétons ces données avec des mesures en domaine submm de télescopes au sol comme APEX ou le JCMT, pour étudier la présence et les caractéristiques de l’excès submm dans mon échantillon de galaxies. Je collecte aussi les données HI et CO pour accéder aux propriétés du gaz dans ces galaxies et étudier l’évolution du rapport en masse gaz-sur-poussière (G/D) avec la métallicité. Notre étude révèle des propriétés de poussière différentes dans les environnements de faible métallicité que celles observées dans des systèmes plus riches en métaux (par exemple, une poussière globalement plus chaude). Une émission en excès par rapport aux modèles utilisés, apparait souvent aux alentours de 500 micromètres, menant à d’importantes incertitudes sur les propriétés de la poussière, notamment sur la masse de poussière. Les excès les moins importants peuvent cependant être expliqués en utilisant une autre composition pour la poussière, avec des grains plus émissifs. Traceur idéal de l’état d’évolution chimique d’une galaxie, le G/D est en fait bien plus grand que ce que l’on pourrait attendre si l’on considère un modèle simple d’évolution chimique. Interprétée avec des modèles d’évolution chimique plus complexes, incorporant des processus de croissance des grains et/ou une formation d’étoiles épisodique, la relation entre le G/D et la métallicité, ainsi que sa dispersion, peuvent être expliquées par la grande variété d’environnements que nous considérons dans notre étude. / As galaxies evolve, their Interstellar Medium (ISM) becomes continually enriched with metals, and this metal enrichment influences the subsequent star formation. Low metallicity dwarf galaxies of the local Universe are ideal candidates to study the influence of metal enrichment on the ISM properties of galaxies and gives us insight into the enrichment process and star formation under ISM conditions that may provide clues to conditions in early universe metal-poor systems. Previous studies have shown that the ISM of dwarf galaxies poses a number of interesting puzzles in terms of the abundance of dust grains, the dust composition and even the FIR emission processes. However these studies were limited to the warmer dust emitting at wavelengths shorter than 200 microns and were done only on a small number of dwarf galaxies. Thanks to its increased sensitivity and resolution in FIR and submillimeter (submm) wavelengths, Herschel gives us a new view on the cold dust properties in galaxies and enables us to study the lowest metallicity galaxies in a systematic way. In this work, I carry out a study of the dust properties in dwarf galaxies and compare with more metal rich environments, in order to address the question of the impact of metallicity on the dust properties. The novelty of this work lays in the fact that dwarf galaxies are studied here in a systematic way, enabling us to derive and quantify the general properties that are representative of these systems. This study is conducted over the full IR-to-submm range, using new FIR/submm Herschel observations, Spitzer, WISE, IRAS and 2MASS data. We complete this set of data with longer submm measurements from ground-based facilities such as APEX and JCMT to study the presence and characteristics of the submm excess in my sample of galaxies. I also collect Hi and CO data to access the gas properties of the galaxies and study the evolution of the G/D with metallicity. Our study reveal different dust properties in low-metallicity environments than that observed in more metal-richs systems (e.g., an overall warmer dust component). An excess submm emission is often apparent near and/or beyond 500 microns rendering large uncertainties in the dust properties, even for something as fundamental as dust masses. Some of the smallest excesses can be explained by using another dust composition with more emissive grains. Ideal tracer of the chemical evolutionary stage of a galaxy, the gas-to-dust mass ratios (G/D) is found to be much higher than what is expected by simple chemical evolution models. Interpreted with more sophisticated chemical evolution models, including dust growth in the ISM and/or episodic star formation, the relation of the G/D with metallicity and its scatter can be explained by the wide variety of environments we are considering.