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The reservoir of molecular gas (H$_{\rm 2}$) represents the fuel for the star formation (SF) of a galaxy. Connecting the star formation rate (SFR) to the available H$_{\rm 2}$ is key to accurately model SF in cosmological simulations of galaxy formation. We investigate how modifying the underlying modelling of H$_{\rm 2}$ and the description of stellar feedback in low-metallicity environments (LMF, i.e. low-metallicity stellar feedback) in cosmological, zoomed-in simulations of a Milky Way-size halo influences the formation history of the forming, spiral galaxy and its final properties. We exploit two different models to compute the molecular fraction of cold gas (f$_{\rm H_{\rm 2}}$): $i)$ the theoretical model by Krumholz et al. (2009b) and $ii)$ the phenomenological prescription by Blitz & Rosolowsky (2006). We find that the model adopted to estimate f$_{\rm H_{\rm 2}}$ plays a key role in determining final properties and in shaping the morphology of the galaxy. The clumpier interstellar medium (ISM) and the more complex H$_{\rm 2}$ distribution that the Krumholz et al. (2009b) model predicts result in better agreement with observations of nearby disc galaxies. This shows how crucial it is to link the SFR to the physical properties of the star-forming, molecular ISM. The additional source of energy that LMF supplies in a metal-poor ISM is key in controlling SF at high redshift and in regulating the reservoir of SF across cosmic time. Not only is LMF able to regulate cooling properties of the ISM, but it also reduces the stellar mass of the galaxy bulge. These findings can foster the improvement of the numerical modelling of SF in cosmological simulations., accepted for publication in MNRAS

We investigate the change in mean stellar population age and metallicity ([Z/H]) scaling relations for quiescent galaxies from intermediate redshift ($0.60\leq z\leq0.76$) using the LEGA-C Survey, to low redshift ($0.014\leq z\leq0.10$) using the SAMI Galaxy Survey. We find that, similarly to their low-redshift counterparts, the stellar metallicity of quiescent galaxies at $0.60\leq z\leq 0.76$ closely correlates with $M_*/R_\mathrm{e}$ (a proxy for the gravitational potential or escape velocity), in that galaxies with deeper potential wells are more metal-rich. This supports the hypothesis that the relation arises due to the gravitational potential regulating the retention of metals, by determining the escape velocity required by metal-rich stellar and supernova ejecta to escape the system and avoid being recycled into later stellar generations. On the other hand, we find no correlation between stellar age and $M_*/R_\mathrm{e}^2$ (stellar mass surface density $\Sigma$) in the LEGA-C sample, despite this being a strong relation at low redshift. We consider this change in the age--$\Sigma$ relation in the context of the redshift evolution of the star-forming and quiescent populations in the mass--size plane, and find our results can be explained as a consequence of galaxies forming more compactly at higher redshifts, and remaining compact throughout their evolution. Furthermore, galaxies appear to quench at a characteristic surface density that decreases with decreasing redshift. The $z\sim 0$ age--$\Sigma$ relation is therefore a result of building up the quiescent and star-forming populations with galaxies that formed at a range of redshifts and so a range of surface densities., Comment: 18 pages, 11 figures, accepted to MNRAS

The development and implementation of GEAR-RT, a radiative transfer solver using the M1 closure in the open source code SWIFT, is presented, and validated using standard tests for radiative transfer. GEAR-RT is modeled after RAMSES-RT (Rosdahl et al. 2013) with some key differences. Firstly, while RAMSES-RT uses Finite Volume methods and an Adaptive Mesh Refinement (AMR) strategy, GEAR-RT employs particles as discretization elements and solves the equations using a Finite Volume Particle Method (FVPM). Secondly, GEAR-RT makes use of the task-based parallelization strategy of SWIFT, which allows for optimized load balancing, increased cache efficiency, asynchronous communications, and a domain decomposition based on work rather than on data. GEAR-RT is able to perform sub-cycles of radiative transfer steps w.r.t. a single hydrodynamics step. Radiation requires much smaller time step sizes than hydrodynamics, and sub-cycling permits calculations which are not strictly necessary to be skipped. Indeed, in a test case with gravity, hydrodynamics, and radiative transfer, the sub-cycling is able to reduce the runtime of a simulation by over 90%. Allowing only a part of the involved physics to be sub-cycled is a contrived matter when task-based parallelism is involved, and is an entirely novel feature in SWIFT. Since GEAR-RT uses a FVPM, a detailed introduction into Finite Volume methods and Finite Volume Particle Methods is presented. In astrophysical literature, two FVPM methods are written about: Hopkins (2015) have implemented one in their GIZMO code, while the one mentioned in Ivanova et al. (2013) isn't used to date. In this work, I test an implementation of the Ivanova et al. (2013) version, and conclude that in its current form, it is not suitable for use with particles which are co-moving with the fluid, which in turn is an essential feature for cosmological simulations., Comment: PhD Thesis

We compare stellar mass surface density, metallicity, age, and line-of-sight velocity dispersion profiles in massive ($M_*\geq10^{10.5}\,\mathrm{M_\odot}$) present-day early-type galaxies (ETGs) from the MaNGA survey with simulated galaxies from the TNG100 simulation of the IllustrisTNG suite. We find an excellent agreement between the stellar mass surface density profiles of MaNGA and TNG100 ETGs, both in shape and normalisation. Moreover, TNG100 reproduces the shapes of the profiles of stellar metallicity and age, as well as the normalisation of velocity dispersion distributions of MaNGA ETGs. We generally also find good agreement when comparing the stellar profiles of central and satellite galaxies between MaNGA and TNG100. An exception is the velocity dispersion profiles of very massive ($M_*\gtrsim10^{11.5}\,\mathrm{M_\odot}$) central galaxies, which, on average, are significantly higher in TNG100 than in MaNGA ($\approx50\,\mathrm{km\,s^{-1}}$). We study the radial profiles of $\mathit{in}$-$\mathit{situ}$ and $\mathit{ex}$-$\mathit{situ}$ stars in TNG100 and discuss the extent to which each population contributes to the observed MaNGA profiles. Our analysis lends significant support to the idea that high-mass ($M_*\gtrsim10^{11}\,\mathrm{M_\odot}$) ETGs in the present-day Universe are the result of a merger-driven evolution marked by major mergers that tend to homogenise the stellar populations of the progenitors in the merger remnant., 22 pages, 9 figures, accepted for publication in MNRAS

We investigate structural properties of massive galaxy populations in the central regions of five very massive galaxy clusters at z~1.4-1.7 from the South Pole Telescope Sunyaev Zel'dovich effect survey. We probe the connection between galaxy structure and broad stellar population properties, at stellar masses log(M/Msun)>10.85. We find that quiescent and star-forming cluster galaxy populations are largely dominated by bulge- and disk-dominated sources, respectively, with relative contributions consistent with those of field counterparts. At the same time, the enhanced quiescent galaxy fraction observed in these clusters with respect to the coeval field is reflected in a significant morphology-density relation, with bulge-dominated galaxies clearly dominating the massive galaxy population in these clusters already at z~1.5. At face value, these observations show no significant environmental signatures in the correlation between broad structural and stellar population properties. In particular, the Sersic index and axis ratio distribution of massive, quiescent sources are consistent with field counterparts, in spite of the enhanced quiescent galaxy fraction in clusters. This consistency suggests a tight connection between quenching and structural evolution towards a bulge-dominated morphology, at least in the probed cluster regions and galaxy stellar mass range, irrespective of environment-related processes affecting star formation in cluster galaxies. We also probe the stellar mass vs. size relation of cluster galaxies, and find that star-forming and quiescent sources populate the mass-size plane in a manner largely similar to their field counterparts, with no evidence of a significant size difference for any probed sub-population. In particular, both quiescent and bulge-dominated cluster galaxies have average sizes at fixed stellar mass consistent with their counterparts in the field., Comment: 17 pages, 10 figures, A&A in press

Recent studies have suggested that red quasars are a phase in quasar evolution when feedback from black hole accretion evacuates obscuring gas from the nucleus of the host galaxy. Here, we report a direct link between dust-reddening and molecular outflows in quasars at $z\sim2.5$. By examining the dynamics of warm molecular gas in the inner region of galaxies, we detect outflows with velocities 500--1000 km s$^{-1}$ and infer timescales of $\approx0.1$ Myr that are due to ongoing quasar energy output. We observe outflows only in systems where quasar radiation pressure on dust in the vicinity of the black hole is sufficiently large to expel their obscuring gas column densities. This result is in agreement with theoretical models that predict radiative feedback regulates gas in the nuclear regions of galaxies and is a major driving mechanism of galactic-scale outflows of cold gas. Our findings suggest that radiative quasar feedback ejects star-forming gas from within nascent stellar bulges at velocities comparable to those seen on larger scales, and that molecules survive in outflows even from the most luminous quasars., Comment: Accepted by MNRAS. 18 figures and 3 tables

Understanding the morphological and dynamical evolution of galaxies across cosmic time is one of the key goals of modern extragalactic astrophysics. Our current view is that galaxies are objects that evolve secularly and build their stellar mass through star formation which is sustained by cold gas accretion from the cosmic web. However, this picture is not sufficient to explain entirely their evolution. Environmental processes can also affect their morphology, kinematics, or gas content, as well as quench star formation, and can thus be driving mechanisms to explain the transition from high to low redshift. Thus, important recent efforts have been put into probing the effect of the environment on galaxies. In this endeavour, 3D spectroscopy can help because it provides spatially resolved properties across the galaxies’ extent. MUSE is one of the most powerful 3D spectrographs thanks to its large field-of-view and high sensitivity when combined with adaptive optics.During this Thesis, I have used data from the deep MUSE-gAlaxy Groups In Cosmos survey (MAGIC) which targets galaxy groups/clusters in the COSMOS field, as well as foreground and background field galaxies. MAGIC is ideal to probe the impact of the environment at 0.2 ≲ z ≲ 1.5 for a large sample of galaxies with high completeness and down to low stellar masses (M⋆ ≈ 10^9 M⊙ ). From this survey, I modelled the morphology of about 900 galaxies by performing a bulge-disk decomposition to extract key morphological parameters (e.g. bulge-to-disk flux ratio, disk inclination, etc.) and the ionised gas kinematics from the MUSE cubes using the [O ii] doublet as kinematics tracer and taking into account beam-smearing for 600 galaxies. I also integrated a mass modelling where I constrained the kinematics using prior information from the bulge-disk decomposition to recover more precise dark matter fractions.This has allowed me to contribute to a first analysis of the Tully-Fisher relation at z ∼ 0.7, followed by my first paper on the analysis of major scaling relations as a function of environment. From these works, I showed that galaxies are affected by their host structure at z ∼ 0.7 in terms of morphology and star-formation rate but not in terms of their dynamics. I continued with another analysis of the impact of the environment on the galaxies’ stellar angular momentum. The first results suggest that there is a visible impact of the environment on the angular momentum, mostly associated to massive galaxies found in the densest parts of the structures. Because these galaxies also host massive bulges, the current interpretation is that they have probably suffered from a depletion of angular momentum (∼ 20%) by building up their bulge component while reaching the inner parts of the structures. Furthermore, I have also worked on the development of a new methodology that produces resolved stellar mass maps using pixel-per-pixel SED fitting techniques and a corresponding machine learning application that I am currently refining.My Thesis has shown the powerful capabilities of MAGIC to probe the impact of the environment on galaxy evolution. This effort will be pushed forward in the near future thanks to already existing and new MUSE surveys such as the HUDF, MUSE-Wide, MXDF, and MUSCATEL. For the latter, I will be able to produce the galaxies’ stellar mass maps and use them to get better constraints on the galaxies’ ionised gas kinematics and on their dark matter content. Furthermore, these new developments combined with my expertise in morpho-kinematics analyses will also be beneficial for future data from next-generation instruments with the JWST or ERIS-VLT and on the longer term with HARMONI and MOSAIC on the ELT.; Comprendre l’évolution morphologique et dynamique des galaxies au cours du temps cosmique est l’un des objectifs principaux de l’astrophysique extragalactique moderne. Notre compréhension actuelle est que les galaxies sont des objets qui évoluent séculairement et qui assemblent leur masse via la formation stellaire entretenue par l’accrétion de gaz froid de la toile cosmique. Cependant, cette image n’est pas suffisante pour expliquer entièrement leur évolution. Des processus environnementaux peuvent aussi affecter leur morphologie, cinématique et contenu en gaz, ainsi que supprimer leur formation stellaire, et donc jouer un rôle majeur pour expliquer la transition de haut à bas redshift. Ainsi, des efforts importants ont récemment été réalisés pour sonder l’effet de l’environnement sur les galaxies. Dans ce but, la spectroscopie 3D peut aider car elle procure des données spatialement résolues des propriétés physiques des galaxies. MUSE est l’un des spectrographes 3D les plus performants grâce à son grand champs de vue et sa haute sensibilité quand il est combiné avec l’optique adaptative.Durant cette thèse, j’ai utilisé des données issues du relevé profond “MUSE gAlaxy Groups In Cosmos survey (MAGIC)” ciblant des groupes/amas de galaxies dans le champs COSMOS, ainsi que des galaxies d’avant et d’arrière plan. MAGIC est idéal pour sonder l’impact de l’environnement à 0.2 ≲ z ≲ 1.5 pour un grand échantillon de galaxies avec une haute complétude et jusqu’à de faibles masses stellaires (M⋆ ≈ 10^9 M⊙ ). Parmi ces données, j’ai modélisé la morphologie d’environ 900 galaxies en réalisant une décomposition bulbe-disque afin d’extraire les paramètres principaux (ratio de flux bulbe-disque, inclinaison du disque, etc.) et la cinématique du gaz ionisé via les cubes MUSE en utilisant le doublet [Oii] comme traceur cinématique et en prenant en compte l’effet du “beam smearing” pour 600 galaxies. J’ai aussi implémenté une modélisation de masse où j’ai contraint la cinématique en utilisant les informations issues de la décomposition bulbe-disque afin d’obtenir des fractions de matière noire plus précises.Cela m’a permis de contribuer à une première analyse de la relation de Tully-Fisher à z ∼ 0.7, suivie de mon premier papier sur l’analyse de plusieurs relations d’échelles majeures en fonction de l’environnement. A partir de ces travaux, j’ai montré que les galaxies sont affectées par leur structure à z ∼ 0.7 au travers de leur morphologie et de leur formation stellaire mais pas de leur dynamique. J’ai poursuivi avec une autre analyse de l’impact de l’environnement sur le moment angulaire stellaire des galaxies. Les premiers résultats suggèrent qu’il y a un impact visible de l’environnement sur le moment angulaire, associé principalement aux galaxies massives localisées dans les zones les plus denses des structures. Étant donné que ces galaxies possèdent des bulbes massifs, l’interprétation actuelle est qu’elles ont probablement souffert d’une déplétion de leur moment angulaire (∼ 20%) durant le processus de formation du bulbe alors qu’elles atteignaient les parties centrales des structures. Qui plus est, j’ai aussi travaillé au développement d’une nouvelle méthode pour produire des cartes de masse résolues via une technique de “SED fitting” pixel par pixel et via une application de “machine learning” que j’affine actuellement. Ma thèse a montré les capacités de MAGIC pour sonder l’effet de l’environnement sur l’évolution des galaxies. Cet effort se poursuivra dans le future proche grâce à d’autre relevés MUSE existants et à venir comme le HUDF, MUSE-Wide, MXDF et MUSCATEL. Pour ce dernier, j’aurai la possibilité de produire des cartes de masse résolues et de les utiliser pour mieux contraindre la cinématique du gaz ionisé et la fraction de matière noire dans les galaxies. Ces nouveaux développements combinés avec mon expertise dans les analyses morpho-cinématiques seront aussi utiles pour de futures données issues d’instruments de prochaine génération avec le JWST ou ERIS-VLT et sur le plus long terme avec HARMONI et MOSAIC sur l’ELT.

Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM, We introduce gizmo-simba, a new suite of galaxy cluster simulations within The Three Hundred project. The Three Hundred consists of zoom re-simulations of 324 clusters with M 200 ≳ 1014.8, M ⊙ drawn from the MultiDark-Planck N-body simulation, run using several hydrodynamic and semi-analytical codes. The gizmo-simba suite adds a state-of-the-art galaxy formation model based on the highly successful Simba simulation, mildly re-calibrated to match z = 0 cluster stellar properties. Comparing to The Three Hundred zooms run with gadget-x, we find intrinsic differences in the evolution of the stellar and gas mass fractions, BCG ages, and galaxy colour-magnitude diagrams, with gizmo-simba generally providing a good match to available data at z ≈ 0. gizmo-simba's unique black hole growth and feedback model yields agreement with the observed BH scaling relations at the intermediate-mass range and predicts a slightly different slope at high masses where few observations currently lie. Gizmo-Simba provides a new and novel platform to elucidate the co-evolution of galaxies, gas, and black holes within the densest cosmic environments

Undisturbed galaxy clusters are characterized by a massive and large elliptical galaxy at their center, i.e. the Brightest Cluster Galaxy (BCG). How these central galaxies form is still debated. According to most models, a typical epoch for their assembly is z~1-2. We have performed a detailed multi-wavelength analysis of the core of XDCPJ0044.0-2033 (XDCP0044), one of the most massive and densest galaxy clusters currently known at redshift z~1.6, whose central galaxy population shows high star formation compared to lower-z clusters and an X-ray AGN located close to its center. SINFONI J-, H- and KMOS YJ-, H- bands spectroscopic data have been analyzed, together with deep archival HST photometric data in F105W, F140W, and F160W bands, Chandra X-ray, radio JVLA data at 1-2 GHz, and ALMA band-6 observations. In the central region of the cluster (~70x70 kpc^2), 2 systems of interacting galaxies have been identified and studied (Complex A and B), with a total of 7 confirmed cluster members. These galaxies show perturbed morphologies and 3 of them show signs of AGN activity. In particular, 2 type-1 AGN with typical broad lines have been found at the center of each complex (both of them X-ray obscured and highly accreting; Eddington ratio ~0.5), while a type-2 AGN has been discovered in Complex A. The AGN at the center of Complex B is also detected in X-ray while the other 2 are spatially related to radio emission. The 3 AGN provide one of the closest AGN triple at z>1 revealed so far with a minimum(maximum) projected distance of ~10(40) kpc. The observation of high star formation, merger signatures and nuclear activity in the core of XDCP0044 suggests that all these processes are key ingredients in shaping the nascent BCG. According to our data, XDCP0044 could form a typical massive galaxy of 10^12 Msun, hosting a Black Hole of 2x10^8-10^9 Msun, in a time scale of the order of ~2.5 Gyrs., 15 pages, 10 figures, 5 tables. Accepted to MNRAS in 2020 August 14

DES Collaboration: P. Wiseman et al., Type Ia supernovae (SNe Ia) are used as standardizable candles to measure cosmological distances, but differences remain in their corrected luminosities which display a magnitude step as a function of host galaxy properties such as stellar mass and rest-frame U−R colour. Identifying the cause of these steps is key to cosmological analyses and provides insight into SN physics. Here we investigate the effects of SN progenitor ages on their light-curve properties using a galaxy-based forward model that we compare to the Dark Energy Survey 5-yr SN Ia sample. We trace SN Ia progenitors through time and draw their light-curve width parameters from a bimodal distribution according to their age. We find that an intrinsic luminosity difference between SNe of different ages cannot explain the observed trend between step size and SN colour. The data split by stellar mass are better reproduced by following recent work implementing a step in total-to-selective dust extinction ratio (RV) between low- and high-mass hosts, although an additional intrinsic luminosity step is still required to explain the data split by host galaxy U−R. Modelling the RV step as a function of galaxy age provides a better match overall. Additional age versus luminosity steps marginally improve the match to the data, although most of the step is absorbed by the width versus luminosity coefficient α. Furthermore, we find no evidence that α varies with SN age., P.W. acknowledges support from the Science and Technology Facilities Council (STFC) grant ST/R000506/1. MS acknowledges support from EU/FP7-ERC grant 615929. LK thanks the UKRI Future Leaders Fellowship for support through the grant MR/T01881X/1. LG acknowledges financial support from the Spanish Ministerio de Ciencia e Innovación (MCIN), the Agencia Estatal de Investigación (AEI) 10.13039/501100011033, and the European Social Fund (ESF) ‘Investing in your future’ under the 2019 Ramón y Cajal program RYC2019-027683-I and the PID2020-115253GA-I00 HOSTFLOWS project, from Centro Superior de Investigaciones Científicas (CSIC) under the PIE project 20215AT016, and the program Unidad de Excelencia María de Maeztu CEX2020-001058-M. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement number 759194 - USNAC). Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência, Tecnologia e Inovação, the Deutsche Forschungsgemeinschaft, and the Collaborating Institutions in the Dark Energy Survey. The Collaborating Institutions are Argonne National Laboratory, the University of California at Santa Cruz, the University of Cambridge, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas-Madrid, the University of Chicago, University College London, the DES-Brazil Consortium, the University of Edinburgh, the Eidgenössische Technische Hochschule (ETH) Zürich, Fermi National Accelerator Laboratory, the University of Illinois at Urbana-Champaign, the Institut de Ciències de l’Espai (IEEC/CSIC), the Institut de Física d’Altes Energies, Lawrence Berkeley National Laboratory, the Ludwig-Maximilians Universität München and the associated Excellence Cluster Universe, the University of Michigan, NSF’s NOIRLab, the University of Nottingham, The Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Accelerator Laboratory, Stanford University, the University of Sussex, Texas A&M University, and the OzDES Membership Consortium. Based in part on observations at Cerro Tololo Inter-American Observatory at NSF’s NOIRLab (NOIRLab Prop. ID 2012B-0001; PI: J. Frieman), which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. The DES data management system is supported by the National Science Foundation under Grant Numbers AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MICINN under grants ESP2017-89838, PGC2018-094773, PGC2018-102021, SEV-2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478. We acknowledge support from the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) do e-Universo (CNPq grant 465376/2014-2). This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.

Recent work has shown that UV-luminous reionization-era galaxies often exhibit strong Lyman-alpha emission despite being situated at redshifts where the IGM is thought to be substantially neutral. It has been argued that this enhanced Ly α transmission reflects the presence of massive galaxies in overdense regions which power large ionized bubbles. An alternative explanation is that massive galaxies shift more of their Ly α profile to large velocities (relative to the systemic redshift) where the IGM damping wing absorption is reduced. Such a mass-dependent trend is seen at lower redshifts, but whether one exists at z ∼ 7 remains unclear owing to the small number of existing systemic redshift measurements in the reionization era. This is now changing with the emergence of [C ii]-based redshifts from ALMA. Here, we report MMT/Binospec Ly α spectroscopy of eight UV-bright (MUV ∼ −22) galaxies at z ≃ 7 selected from the ALMA REBELS survey. We detect Ly α in four of eight galaxies and use the [C ii] systemic redshifts to investigate the Ly α velocity profiles. The Ly α lines are significantly redshifted from systemic (average velocity offset = 223 km s–1) and broad (FWHM ≈ 300–650 km s−1), with two sources showing emission extending to ≈750 km s−1. We find that the broadest Ly α profiles are associated with the largest [C ii] line widths, suggesting a potential link between the Ly α FWHM and the dynamical mass. Since Ly α photons at high velocities transmit efficiently through the z = 7 IGM, our data suggest that velocity profiles play a significant role in boosting the Ly α visibility of the most UV-luminous reionization-era galaxies.

Identifying very high-redshift galaxies is crucial for understanding the formation and evolution of galaxies. However, many questions still remain, and the uncertainty on the epoch of reionization is large. In this approach, some models allow a double-reionization scenario, although the number of confirmed detections at very high $z$ is still too low to serve as observational proof. The main goal of this project is studying whether we can search for Lyman-$\alpha$ emitters (LAEs) at $z \sim 9$ using a narrow-band (NB) filter that was specifically designed by our team and was built for this experiment. We used the NB technique to select candidates by measuring the flux excess due to the Ly$\alpha$ emission. The observations were taken with an NB filter (full width at half minimum of 11 nm and central wavelength $\lambda_{c} = 1.257 \mu$m) and the CIRCE near-infrared camera for the GTC. We describe a data reduction procedure that was especially optimized to minimize instrumental effects. With a total exposure time of 18.3 hours, the final NB image covers an area of $\sim 6.7$ arcmin$^{2}$, which corresponds to a comoving volume of $1.1 \times 10^{3}$ Mpc$^{3}$ at $z = 9.3$. We pushed the source detection to its limit, which allows us to analyze an initial sample of 97 objects. We detail the different criteria we applied to select the candidates. The criteria included visual verifications in different photometric bands. None of the objects resembled a reliable LAE, however, and we found no robust candidate down to an emission-line flux of $2.9 \times 10^{-16}$ erg s$^{-1} $cm$^{-2}$, which corresponds to a Ly$\alpha$ luminosity limit of $3 \times 10^{44}$ erg s$^{-1}$. We derive an upper limit on the Ly$\alpha$ luminosity function at $z \sim 9$ that agrees well with previous constraints. We conclude that deeper and wider surveys are needed to study the LAE population at the cosmic dawn., Comment: 17 pages, 12 figures, accepted for publication in Astronomy & Astrophysics

Some spiral galaxies have a hot gas component displaying a thick disk or halo structure known as a diffuse ionised gas (DIG). In galaxies viewed edge-on, it is possible to study the longitudinal motions in the galactic plane and the vertical kinematics without confusion with the gas in the disk. DIG layers detected several kpc out of the galactic plane are called extra-planar DIG (eDIG). A key galactic property governing the presence of the eDIG is the star-forming activity (SFR) of the galaxy, but it is still unclear whether the ionisation of the eDIG is due to radiation from massive stars, as is the case in HII regions, or whether other sources of ionisation should be considered. The eDIG has different kinematic properties than the ionised gas surrounding the stars in the thin galactic disk. The rotational velocity of the disc decreases with vertical distribution, it can be described by a disc-halo flow model in which the gas is transported from the disc to the halo where the gravitational potential is lower and the gas moves radially outwards, its rotational velocity decreases but it keeps its angular momentum. Fabry-Perot interferometry offers full two-dimensional coverage over a large field of view and high sensitivity to detect diffuse H-alpha emission with high spectral resolution. In this work, we studied H-alpha data acquired using this technique for two samples of galaxies viewed edge-on in order to understand the prominence and kinematics of the eDIG. Moreover, to discriminate the gas emission in the disk from the gas emission outside the disk seen in projection, the near-infrared (NIR) data provide a distinctive view of the old stellar component which constitute the major fraction of the baryonic mass in the disk. Thus, we used the NIR images from the Digitized Sky Survey and 2MASS to trace the galactic disks. The first sample consists of 43 late-type galaxies with inclination higher than 75 deg, it was extracted from the catalogue ‘The Herschel Reference Survey (HRS)’. Particular features of interactive galaxies with the ICM, both photometric and kinematic, were detected in 24 out of 43 galaxies in this sample. As the evolution of galaxies can be strongly perturbed by the environment, a reference sample of 14 galaxies of similar morphological type and inclination was selected from the ‘Catalogue of Isolated Galaxies (CIG)’. Preliminary results show that in isolated galaxies the amplitude of the rotational lagging increases with their intrinsic SFR. The large spiral galaxy of the Virgo cluster, NGC 4330, is undergoing important transformations due to the density of its environment, hence it is representative of the HRS sample. For this galaxy, it was performed a photometric analysis to the NGVS i−band image and to the VESTIGE narrowband H-alpha image. The kinematics of the ionised gas in NGC 4330 detected with FP interferometry allowed us to reconstruct the dynamical interaction of the galaxy with the intergalactic medium. The analysis to the velocity field, velocity dispersion field, rotation curves and PVDs indicated that outer disk regions do not follow the solid-body rotation but have peculiar velocities indicative of streaming motions out of the galactic plane driven by the ram-pressure stripping acting almost perpendicularly to the plane of the disk. We also studied kinematic similarities between the hot and cold (atomic and molecular) gas of this galaxy.; Certaines galaxies spirales ont une composante de gaz chaud localisée dans une structure épaisse appelé gaz diffus ionisé (DIG). Dans les galaxies vues par la tranche, il est possible d’étudier les mouvements longitudinaux dans le plan de la galaxie et la cinématique verticale sans confusion avec le gaz dans le disque. Les couches de DIG détectées à plusieurs kpc hors du plan galactique sont appelées DIG extra-planaire (eDIG). Une propriété galactique essentielle qui régit l’existence d’eDIG est l’activité de formation stellaire de la galaxie, mais il n’est toujours pas clair si l’ionisation de l’eDIG est dû au rayonnement des étoiles massives, comme c’est le cas dans les régions HII, ou si d’autres sources d’ionisation doivent être considérées. L’eDIG présente des propriétés cinématiques différentes de celles du gaz ionisé entourant les étoiles du disque galactique mince. La vitesse de rotation du disque décroit avec la distribution verticale, elle peut être décrite par un modèle dans lequel le gaz est transporté du disque vers le halo, où le potentiel gravitationnel est plus faible et le gaz s’y déplace radialement vers l’extérieur, sa vitesse de rotation décroît mais il conserve son moment angulaire. L’interférométrie de Fabry-Perot offre une couverture bidimensionnelle complète sur un grand champ de vue et une grande sensibilité pour détecter l’émission H-alpha diffuse avec haute résolution spectrale. Dans ce travail, nous avons étudié des données H-alpha acquises à l’aide de cette technique pour deux échantillons de galaxies vues par la tranche afin de comprendre la prédominance et la cinématique de l’eDIG. En complément, pour distinguer l’émission du gaz dans le disque de celle en dehors du disque, des données infrarouges proches (NIR) permettent de tracer les composantes stellaires qui constituent l’essentiel de la masse baryonique dans le disque. Ainsi, les images des bandes IR du Digitized Sky Survey et de 2MASS ont été employées pour tracer les disques galactiques. Le premier échantillon, constitué par 43 galaxies de type tardif ayant une inclinaison supérieure à 75 degrés, a été extrait du catalogue ‘The Herschel Reference Survey (HRS)’. Des caractéristiques particulières des galaxies en interaction avec le milieu intergalactique, autant photométriques que cinématiques, ont été détectées pour 24 des 43 galaxies de cet échantillon. Comme l’évolution séculaire des galaxies peut être fortement perturbé par l’environnement, un second échantillon de référence de 14 galaxies de type morphologique et d’inclination similaires a été sélectionné à partir d’un autre catalogue, le ‘Catalogue de Galaxies Isolées (CIG)’. Les résultats préliminaires montrent que, dans les galaxies isolées, l’amplitude du décalage de rotation augmente avec leur SFR intrinsèque. La grande galaxie spirale de l’amas de la vierge, NGC 4330, est soumise à des transformations majeures dues à la densité de son environnement, donc elle est une galaxy représentative d’échantillon HRS. Pour cet galaxie, il a été effectuée l’analyse photométrique de l’image de la bande ‘i’ du sondage NGVS et de l’image Hαen bande étroite du sondage VESTIGE. La cinématique du gaz ionisé de NGC 4330 permet de reconstruire l’interaction dynamique de la galaxie avec le milieu intergalactique. L’analyse des champs de vitesses et de dispersion de vitesses, des courbes de rotation et des diagrammes position-vitesses montrent que l’eDIG n’accompagne pas la rotation en corps solide du disque mais qu’il suit des courants (streaming) hors du plan de la galaxie, qui sont causés par le stripping du gaz agissant de façon quasi perpendiculaire au plan du disque. Les similitudes cinématiques entre le gaz chaud et le gaz froid (atomique et moléculaire) de cet galaxie ont été aussi étudiées.

We study molecular outflows in a sample of 25 nearby (z< 0.17, d 300 km/s) molecular gas disconnected from the galaxy rotation, which we attribute to outflows. In 77% of the 26 nuclei with $\log L_{IR}/L_{\odot}>11.8$, we identifid molecular outflows with an average $v_{out}= 490$ km/s, outflow masses $1-35 \times 10^7$ $M_{\odot}$, mass outflow rates $\dot{M}_{out}=6-300$ $M_{\odot}$ yr$^{-1}$, mass-loading factors $η= \dot{M}_{out}/SFR = 0.1-1$, and an average outflow mass escape fraction of 45%. The majority of these outflows (18/20) are spatially resolved with radii of 0.2-0.9 kpc and have short dynamical times ($t_{dyn}=R_{out}/v_{out}$) in the range 0.5-2.8 Myr. The outflow detection rate is higher in nuclei dominated by starbursts (SBs, 14/15=93%) than in active galactic nuclei (AGN, 6/11=55%). Outflows perpendicular to the kinematic major axis are mainly found in interacting SBs. We also find that our sample does not follow the $\dot{M}_{out}$ versus AGN luminosity relation reported in previous works. In our analysis, we include a sample of nearby main-sequence galaxies (SFR = 0.3-17 $M_{\odot}$ yr$^{-1}$) with detected molecular outflows from the PHANGS-ALMA survey to increase the $L_{IR}$ dynamic range. Using these two samples, we find a correlation between the outflow velocity and the SFR, as traced by $L_{IR}$ ($v_{out} \propto SFR^{0.25\pm0.01})$, which is consistent with what was found for the atomic ionised and neutral phases. Using this correlation, and the relation between $M_{out}/R_{out}$ and $v_{out}$, we conclude that these outflows are likely momentum-driven., 27 pages, 23 figures; Appendix: 49 pages, 41 figures. Accepted for publication in Astronomy & Astrophysics. Typo corrected in Table 1 for galaxy 19297-0406

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2021, Tutor: Josep Maria Solanes Majúa, We present a study of double-peaked (DP) emission-line galaxies at z < 0:1 based on a subset of 84; 492 spectra extracted from the SDSS catalog. We have performed an automated selection procedure of DP spectra by adapting a previously existing routine developed for stars. A total of 5; 682 galaxies of the parent database have been found to exhibit a significant double peak in at least one of the four emission lines traditionally used in the Baldwin, Phillips and Terlevich (BPT) diagrams to discriminate among different ionization mechanisms. A preliminary investigation on the possible existence of an anti-correlation between the ratios of fluxes from the [OIII] λ 5007 line and velocity shifts of the red and blue components of the DP lines has produced results independent of the BPT classification of the galaxies. For most of the outliers of this relationship we find that the position of the strong [OIII] peak is significantly closer to the stellar velocity than for the weak [OIII] peak. These off-centered outliers could be linked to minor mergers in which central star formation has been enhanced or to objects with asymmetric gas out ows.

International audience; Galactic winds constitute a primary feedback process in the ecology and evolution of galaxies. They are ubiquitously observed and exhibit a rich phenomenology, whose origin is actively investigated both theoretically and observationally. Cosmic rays have been widely recognized as a possible driving agent of galactic winds, especially in Milky–Way like galaxies. The formation of cosmic ray-driven winds is intimately connected with the microphysics of the cosmic ray transport in galaxies, making it an intrinsically non-linear and multiscale phenomenon. In this complex interplay, the cosmic ray distribution affects the wind launching and, in turns, is shaped by the presence of winds. In this review, we summarize the present knowledge of the physics of cosmic rays involved in the wind formation and of the wind hydrodynamics. We also discuss the theoretical difficulties connected with the study of cosmic ray-driven winds and possible future improvements and directions.

Shin, T., et al., We present measurements of the radial profiles of the mass and galaxy number density around Sunyaev–Zel’dovich (SZ)-selected clusters using both weak lensing and galaxy counts. The clusters are selected from the Atacama Cosmology Telescope Data Release 5 and the galaxies from the Dark Energy Survey Year 3 data set. With signal-to-noise ratio of 62 (45) for galaxy (weak lensing) profiles over scales of about 0.2–20 h Mpc, these are the highest precision measurements for SZ-selected clusters to date. Because SZ selection closely approximates mass selection, these measurements enable several tests of theoretical models of the mass and light distribution around clusters. Our main findings are: (1) The splashback feature is detected at a consistent location in both the mass and galaxy profiles and its location is consistent with predictions of cold dark matter N-body simulations. (2) The full mass profile is also consistent with the simulations. (3) The shapes of the galaxy and lensing profiles are remarkably similar for our sample over the entire range of scales, from well inside the cluster halo to the quasilinear regime. We measure the dependence of the profile shapes on the galaxy sample, redshift, and cluster mass. We extend the Diemer & Kravtsov model for the cluster profiles to the linear regime using perturbation theory and show that it provides a good match to the measured profiles. We also compare the measured profiles to predictions of the standard halo model and simulations that include hydrodynamics. Applications of these results to cluster mass estimation, cosmology, and astrophysics are discussed., The DES data management system is supported by the National Science Foundation under Grant Numbers AST-1138766 and AST-1536171. The DES participants from Spanish institutions are partially supported by MICINN under grants ESP2017-89838, PGC2018-094773, PGC2018-102021, SEV-2016-0588, SEV-2016-0597, and MDM-2015-0509, some of which include ERDF funds from the European Union. IFAE is partially funded by the CERCA program of the Generalitat de Catalunya. Research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Program (FP7/2007-2013) including ERC grant agreements 240672, 291329, and 306478. We acknowledge support from the Brazilian Instituto Nacional de Ciência e Tecnologia (INCT) do e-Universo (CNPq grant no. 465376/2014-2).

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2021, Tutor: Alberto Manrique Oliva, Galaxies have been the main protagonist in Cosmology and the study of the Universe for almost a century. Currently, they have become an independent and major field itself. Through the use of AMIGA, an analytic model that examines galaxy formation and evolution since the dark ages, we will study the roles of accretion and mergers as two different ways for galaxies to grow. The model will provide the ratio of mass coming from mergers for several ages. This ratio will be shown according to two different variables: the stellar mass of galaxies and the age of the Universe. We see that the role of mergers increased from z ∼ 10 to z ∼ 4, and had its peak at z ≈ 5, with a value of 30%. This tendency is supported by recent studies on luminosity functions. Finally, even though mergers were the most significant process in the formation of the most massive galaxies, accretion has had the major role in galaxy growth

Using the DIANOGA hydrodynamical zoom-in simulation set of galaxy clusters, we analyze the dynamics traced by stars belonging to the Brightest Cluster Galaxies (BCGs) and their surrounding diffuse component, forming the intracluster light (ICL), and compare it to the dynamics traced by dark matter and galaxies identified in the simulations. We compute scaling relations between the BCG and cluster velocity dispersions and their corresponding masses (i.e. $M_\mathrm{BCG}^{\star}$- $\sigma_\mathrm{BCG}^{\star}$, $M_{200}$- $\sigma_{200}$, $M_\mathrm{BCG}^{\star}$- $M_{200}$, $\sigma_\mathrm{BCG}^{\star}$- $\sigma_{200}$), we find in general a good agreement with observational results. Our simulations also predict $\sigma_\mathrm{BCG}^{\star}$- $\sigma_{200}$ relation to not change significantly up to redshift $z=1$, in line with a relatively slow accretion of the BCG stellar mass at late times. We analyze the main features of the velocity dispersion profiles, as traced by stars, dark matter, and galaxies. As a result, we discuss that observed stellar velocity dispersion profiles in the inner cluster regions are in excellent agreement with simulations. We also report that the slopes of the BCG velocity dispersion profile from simulations agree with what is measured in observations, confirming the existence of a robust correlation between the stellar velocity dispersion slope and the cluster velocity dispersion (thus, cluster mass) when the former is computed within $0.1 R_{500}$. Our results demonstrate that simulations can correctly describe the dynamics of BCGs and their surrounding stellar envelope, as determined by the past star-formation and assembly histories of the most massive galaxies of the Universe., Comment: 16 pages, 14 figures

In the last few decades, observational evidence showed that spheroidal stellar systems display large kinematic diversity. From the largest galaxies to the smallest star clusters, the velocity distribution of stars displays both various flavours of anisotropy (preference for more elongated or more circular orbits), as well as net angular momentum (preferred direction of the azimuthal velocity). This diversity was also shown to vary with cosmic time, through brutal changes and steady perturbations. These observations recently triggered a revived interest for the modelling of spheroidal stellar systems with various anisotropy and rotation profiles. Meanwhile, the stability and evolution of anisotropic, rotating spheroidal systems were scarcely studied. What degree of anisotropy and rotation is expected at the formation of these structures, and at various epochs of their evolution? How do they evolve, in isolation? How does the environment impact their kinematics? In all these prospects, the linear response of stellar clusters is central to their fate. On the one hand, understanding how stable they are is necessary for their consistent modelling. Indeed, it identifies the ensemble of authorised states in which star clusters can be at the time of their observation. On the other hand, identifying the attractors among the stable equilibria is critical to analyse the way they can evolve and interact with their environment, therefore putting constraints on their scenarios of formation and evolution. Here, I use the response matrix method to evaluate the linear response of spherical equilibria, and complement it with N-body simulations. I extend the matrix method to rotating clusters, where the matrix has an extra degree of freedom, and develop numerical techniques leading to its fast computation. This allows me to perform numerous stability analyses, on many clusters with various degrees and flavours in their velocity anisotropy, and different degrees and distributions of net angular momentum. Since star clusters are intrinsically resonant systems, I interpret the stability of rotating, anisotropic star clusters using three known resonant destabilising processes: the radial orbit instability (ROI) in radially anisotropic systems, the circular orbits instability (COI) in tangentially anisotropic systems, and the tumbling instability (TI) in rotating systems. I find that non-rotating clusters with sufficient velocity anisotropy are unstable, both in the radial (ROI) and in the tangential regime (COI). Rotation further enhances the destabilisation of anisotropic systems (through the TI), hence it narrows down the authorised stability domain around isotropic systems. This means that stable spherical clusters can only have a low amount of anisotropy and rotation, and conversely that highly anisotropic or fast rotating clusters cannot be spherical. From a detailed study of destabilising processes, both in terms of resonances via linear theory, and in terms of location in the cluster via N-body simulations, I develop a stability criterion for tangentially anisotropic, rotating spheres with high shear, which reproduces the stability boundary of a large sample of simulations. These results show that resonant processes and self-sustained modes can be important drivers of the secular evolution of spheroidal star clusters with intricate kinematics. It will prove of prime importance at a time when ab initio cosmological simulations reach sufficient resolution to resolve their dynamics, to best make sense of how they evolve over a Hubble time.; Ces dernières décennies, des preuves observationnelles ont montré que les systèmes stellaires sphéroïdaux présentent une importante diversité cinématique. Des plus grandes galaxies aux plus petits amas stellaires, la distribution de vitesse des étoiles présente de l’anisotropie dans différentes directions (une préférence pour les orbites plutôt allongées ou plutôt circulaires), ainsi que de la rotation globale (une direction préférentielle de la vitesse azimutale). Il a aussi été montré que cette diversité varie au cours de l’histoire de l’Univers, par des changements brutaux ou des perturbations régulières. Ces observations ont ainsi récemment renouvelé l’intérêt de la modélisation de systèmes stellaires sphériques présentant des profils d’anisotropie et de rotation divers. Cependant, la stabilité et l’évolution des systèmes sphéroïdaux anisotropes en rotation a été peu étudiée. À quel degré d’anisotropie et de rotation s’attend-on après la formation de ces structures, et à différentes époques de leur évolution ? Comment évoluent-elles lorsqu’elles sont isolées? Comment leur environnement influe-t-il sur leur cinématique? La réponse linéaire de ces objets joue un rôle central dans leur destin. D’une part, la compréhension de leur stabilité est nécessaire à une modélisation cohérente. En effet, on peut alors identifier l’ensemble des états autorisés dans lesquels les amas stellaires peuvent être lorsqu’on les observe. D’autre part, l’identification des attracteurs parmi l’ensemble des équilibres stables est critique pour analyser la manière dont ils évoluent et interagissent avec leur environnement, ce qui permet de contraindre leurs scénarios de formation et d’évolution. Dans cette thèse, j’utilise la méthode de la matrice de réponse, complémentée par des simulations à N corps, pour évaluer la stabilité linéaire d’équilibres sphériques. J’étends cette méthode des matrices aux amas en rotation, ce qui lui donne un degré de liberté supplémentaire, et je développe des méthodes numériques qui optimisent son évaluation. Ces nouvelles méthodes me permettent d’effectuer de nombreuses analyses de stabilité, sur de nombreux amas présentant de l’anisotropie à des degrés et saveurs divers, ainsi qu’une variété dans l’amplitude et la distribution du moment angulaire net. Comme les amas stellaires sont des systèmes intrinsèquement résonants, j’interprète la stabilité des amas stellaires anisotropes en rotation par le biais de trois processus résonnants de déstabilisation connus : l’instabilité d’orbite radiale (ROI) dans les systèmes radialement anisotropes, l’instabilité d’orbite circulaire (COI) dans les systèmes tangentiellement anisotropes, et l’instabilité d’alignement (TI) dans les systèmes tournants. Je montre que les systèmes sans rotation présentant un haut degré d’anisotropie sont instables, autant dans le régime radial (ROI) que dans le régime tangentiel (COI). La rotation entraîne la déstabilisation des systèmes anisotropes (via la TI), ce qui réduit d’autant le domaine de stabilité autour des systèmes isotropes. Cela signifie que les amas sphériques stables ne peuvent pas avoir une anisotropie ou une rotation importantes, et à l’inverse que des systèmes fortement anisotropes ou en rotation rapide ne peuvent pas être sphériques. À partir d’une étude détaillée des processus de déstabilisation, d’une part en termes de résonances avec la méthode des matrices, d’autre part en termes de position dans l’amas grâce à des simulations à N corps, je présente un critère de stabilité pour les sphères tangentiellement anisotropes en rotation et avec fort cisaillement, en accord avec la limite de stabilité d’un large échantillon de simulations. Ces résultats montrent que les processus résonnants et les modes auto-maintenus peuvent être des sources importantes de l’évolution séculaire des amas stellaires sphéroïdaux à haute complexité cinématique. Ces résultats ont une importance particulière à une époque où les simulations cosmologiques atteignent une résolution suffisante pour analyser leur dynamique, afin de mieux comprendre comment ils évoluent au cours de l’histoire de l’Univers.

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2020, Tutors: Friedrich Anders, Mercè Romero-Gómez, We review some of the traits of the Galactic disc and elaborate on the Milky Way's Warp, the recent studies investigating it, and its importance. We focus on the effect of this distortion on different age populations using a broad sample of young objects made up by Cepheids, masers, and HII regions. We attempt a fit on this sample and compare it to other populations models available in the literature. We find less agreement with the similar age population OB model than expected, although some general trends are shared among all the models plotted. We also compare the positions of objects in our sample with respect to a HI Model, but find no evidence regarding a warping trend with age.

The baryonic component of the Large Scale Structure (LSS) of the Universe is composed by concentrations of gas and galaxies forming groups, clusters, elongated filaments and widely spread sheets which probably underline the distribution of dark matter. Nevertheless, according to the current cosmological models, most of the baryonic material in the Universe has not yet been directly observed. Numerical simulations suggest that from one-half to two-thirds of all baryons may be located out of clusters of galaxies, pervading the structures between them. The most concentrated structures, which we call systems of galaxies (i.e., groups and clusters) usually contain high density hot gas (1 - 10 keV) that cools radiatively, emits at X-rays wavelengths and interacts with the cosmic microwave background at millimeter wavelengths (Sunyaev Zel'dovich effect, SZ). For the less dense structures, filaments and sheets, the baryons are probably in moderately hot gas phase (0.01 - 1 keV), commonly named as warm hot intergalactic medium (WHIM). In this PhD Thesis, we study the environmental effects associated to the different components of the LSS. For the galaxy systems, we aim to characterize the intra cluster medium (ICM) through the analysis of the S-Z effect. We employ the ACT and Planck data to analyze the gas pressure profiles of a sample of low mass galaxy clusters. For the least dense structures, we assembled a sample of filament candidates composed by chains of clusters that are located inside superclusters of galaxies. We aim to probe the filament structure skeletons and characterize their components (galaxies, groups/clusters and gas).; La composante baryonique de la structure à grande échelle de l’Univers est composée de concentration de gaz et de galaxies, donnant lieu à des groupes, à des amas, à des filaments allongés et à des murs étendus. Ces structures peuvent suivre la distribution de matière noire dans l’Univers. Néanmoins, selon le modèle cosmologique actuel, l’ensemble des matières baryoniques dans l’Univers n’a pas encore été observé. Cependant, les simulations numériques nous suggèrent qu’entre la moitié et deux tiers des parties des baryons sont localisées entre les amas de galaxies et peuplent les structures qui les relient. Les structures les plus concentrées, que nous appelons ici « des systèmes » (i.e. groupes et amas), ont généralement des gaz à haute concentration et une température élevée (1 - 10 keV). Cette température se refroidit en émettant des photons qui sont observables en rayons X. De plus les gaz interagissent avec les photons du fond diffuse cosmologique par l’effet Sunyaev–Zel'dovich (SZ) , observable à longueur d’onde millimétrique. Dans les filamentaires et murs qui sont des structures moins denses, les baryons sont probablement dans un état moins dense et à une température modérée (0.01 - 1 keV). Ces gaz tièdes sont appelés WHIM (Warm Hot Intergalactic Medium). Pendant cette Thèse de doctorat nous étudions les effets environnementaux associés aux différents composants de la structure à grande échelle de l’Univers. Pour les systèmes, l'objectif est la caractérisation du milieu intra amas en utilisant l’effet SZ. Pour cela nous utilisons les observations du satellite Planck et de l’Atacama Cosmological Télescope (ACT) afin d’analyser les profils de pression pour un échantillon d’amas de faible masse. D'autre part, pour l'étude des structures à faible densité (structures filamentaires). Nous avons construit un échantillon de candidats à filaments, cet échantillon se compose des chaînes d’amas reliées en une structure de super amas de galaxies. Notre objectif est de prouver leur nature filamentaire et de caractériser ses composants (galaxies, amas et gaz).

The baryonic component of the Large Scale Structure (LSS) of the Universe is composed by concentrations of gas and galaxies forming groups, clusters, elongated filaments and widely spread sheets which probably underline the distribution of dark matter. Nevertheless, according to the current cosmological models, most of the baryonic material in the Universe has not yet been directly observed. Numerical simulations suggest that from one-half to two-thirds of all baryons may be located out of clusters of galaxies, pervading the structures between them. The most concentrated structures, which we call systems of galaxies (i.e., groups and clusters) usually contain high density hot gas (1 - 10 keV) that cools radiatively, emits at X-rays wavelengths and interacts with the cosmic microwave background at millimeter wavelengths (Sunyaev Zel'dovich effect, SZ). For the less dense structures, filaments and sheets, the baryons are probably in moderately hot gas phase (0.01 - 1 keV), commonly named as warm hot intergalactic medium (WHIM). In this PhD Thesis, we study the environmental effects associated to the different components of the LSS. For the galaxy systems, we aim to characterize the intra cluster medium (ICM) through the analysis of the S-Z effect. We employ the ACT and Planck data to analyze the gas pressure profiles of a sample of low mass galaxy clusters. For the least dense structures, we assembled a sample of filament candidates composed by chains of clusters that are located inside superclusters of galaxies. We aim to probe the filament structure skeletons and characterize their components (galaxies, groups/clusters and gas).; La composante baryonique de la structure à grande échelle de l’Univers est composée de concentration de gaz et de galaxies, donnant lieu à des groupes, à des amas, à des filaments allongés et à des murs étendus. Ces structures peuvent suivre la distribution de matière noire dans l’Univers. Néanmoins, selon le modèle cosmologique actuel, l’ensemble des matières baryoniques dans l’Univers n’a pas encore été observé. Cependant, les simulations numériques nous suggèrent qu’entre la moitié et deux tiers des parties des baryons sont localisées entre les amas de galaxies et peuplent les structures qui les relient. Les structures les plus concentrées, que nous appelons ici « des systèmes » (i.e. groupes et amas), ont généralement des gaz à haute concentration et une température élevée (1 - 10 keV). Cette température se refroidit en émettant des photons qui sont observables en rayons X. De plus les gaz interagissent avec les photons du fond diffuse cosmologique par l’effet Sunyaev–Zel'dovich (SZ) , observable à longueur d’onde millimétrique. Dans les filamentaires et murs qui sont des structures moins denses, les baryons sont probablement dans un état moins dense et à une température modérée (0.01 - 1 keV). Ces gaz tièdes sont appelés WHIM (Warm Hot Intergalactic Medium). Pendant cette Thèse de doctorat nous étudions les effets environnementaux associés aux différents composants de la structure à grande échelle de l’Univers. Pour les systèmes, l'objectif est la caractérisation du milieu intra amas en utilisant l’effet SZ. Pour cela nous utilisons les observations du satellite Planck et de l’Atacama Cosmological Télescope (ACT) afin d’analyser les profils de pression pour un échantillon d’amas de faible masse. D'autre part, pour l'étude des structures à faible densité (structures filamentaires). Nous avons construit un échantillon de candidats à filaments, cet échantillon se compose des chaînes d’amas reliées en une structure de super amas de galaxies. Notre objectif est de prouver leur nature filamentaire et de caractériser ses composants (galaxies, amas et gaz).

We study the effects of the integrated galactic initial mass function (IGIMF) and dust evolution on the abundance patterns of high redshift starburst galaxies. In our chemical models, the rapid collapse of gas clouds triggers an intense and rapid star formation episode, which lasts until the onset of a galactic wind, powered by the thermal energy injected by stellar winds and supernova explosions. Our models follow the evolution of several chemical elements (C, N, $\alpha$-elements and Fe) both in the gas and dust phases. %The most recent stellar yield and dust prescriptions are adopted. We test different values of $\beta$, the slope of the embedded cluster mass function for the IGIMF, where lower $\beta$ values imply a more top-heavy initial mass function (IMF). The computed abundances are compared to high-quality abundance measurements obtained in lensed galaxies and from composite spectra in large samples of star-forming galaxies in the redshift range $2 \lesssim z \lesssim 3$. The adoption of the IGIMF causes a sensible increase of the rate of star formation with respect to a standard Salpeter IMF, with a strong impact on chemical evolution. We find that in order to reproduce the observed abundance patterns in these galaxies, either we need a very top-heavy IGIMF ($\beta < 2$) or large amounts of dust. In particular, if dust is important, the IGIMF should have $\beta \ge 2$, which means an IMF slightly more top-heavy than the Salpeter one. The evolution of the dust mass with time for galaxies of different mass and IMF is also computed, highlighting that the dust amount increases with a top-heavier IGIMF., Comment: 21 pages, 14 Figures. Accepted for publication in MNRAS

The SINFONI survey for Unveiling the Physics and Effect of Radiative feedback (SUPER) aims at tracing and characterizing ionized gas outflows and their impact on star formation in a statistical sample of X-ray selected Active Galactic Nuclei (AGN) at z$\sim$2. We present the first SINFONI results for a sample of 21 Type-1 AGN spanning a wide range in bolometric luminosity (log $\mathrm{L_{bol}}$ = 45.4-47.9 erg/s). The main aims of this paper are determining the extension of the ionized gas, characterizing the occurrence of AGN-driven outflows, and linking the properties of such outflows with those of the AGN. We use Adaptive Optics-assisted SINFONI observations to trace ionized gas in the extended narrow line region using the [OIII]5007 line. We classify a target as hosting an outflow if its non-parametric velocity of the [OIII] line, $\mathrm{w_{80}}$, is larger than 600 km/s. We study the presence of extended emission using dedicated point-spread function (PSF) observations, after modelling the PSF from the Balmer lines originating from the Broad Line Region. We detect outflows in all the Type-1 AGN sample based on the $\mathrm{w_{80}}$ value from the integrated spectrum, which is in the range 650-2700 km/s. There is a clear positive correlation between $\mathrm{w_{80}}$ and the AGN bolometric luminosity (99% correlation probability), but a weaker correlation with the black hole mass (80% correlation probability). A comparison of the PSF and the [OIII] radial profile shows that the [OIII] emission is spatially resolved for $\sim$35% of the Type-1 sample and the outflows show an extension up to $\sim$6 kpc. The relation between maximum velocity and the bolometric luminosity is consistent with model predictions for shocks from an AGN driven outflow. The escape fraction of the outflowing gas increase with the AGN luminosity, although for most galaxies, this fraction is less than 10%., Accepted for publication in A&A, 34 pages, 14 figures and 5 tables

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2019, Tutor: José María Solanes Majúa, We investigate the process of dynamical friction from the point of view of the dynamics of galaxy mergers. We are particularly interested in providing an accurate formula for the merger time between galactic halos of similar mass, also known as major mergers. We have reviewed the theoretical foundations of this mechanism, as well as used 605 isolated simulations of binary collisions of galaxies to test a new non-separable expression for the merger timescale. Our study reveals some plausible reasons why merger time formulas existing in the literature may not perform successfully for major mergers, related to both the theory and the methodology applied in the analysis of numerical results.

We use Gaia DR2 magnitudes, colours and parallaxes for stars with G1.53 Msun and $��_2 \approx 1.3$ for the mass range between 0,5 and 1,53 Msun. This is the first time that we consider a non-parametric SFH for the thin disc in the Besancon Galaxy Model. This new step, together with the capabilities of the Gaia DR2 parallaxes to break degeneracies between different stellar populations, allow us to better constrain the SFH and the IMF., 6 pages, 3 figures. Accepted for publication to A&A letters

We explore the constraints that can be placed on the evolutionary timescales for typical low redshift galaxies evolving from the blue cloud through the green valley and onto the red sequence. We utilise galaxies from the GAMA survey with 0.1 < z < 0.2 and classify them according to the intrinsic (u-r?) colours of their stellar populations, as determined by fits to their multi-wavelength spectral energy distributions. Using these fits to also determine stellar population ages and star formation timescales, we argue that our results are consistent with a green valley population dominated by galaxies that are simply decreasing their star formation (running out of gas) over a timescale of 2-4 Gyr which are seen at a specific epoch in their evolution (approximately 1.6 e-folding times after their peak in star formation). If their fitted star formation histories are extrapolated forwards, the green galaxies will further redden over time, until they attain the colours of a passive population. In this picture, no specific quenching event which cuts-off their star formation is required, though it remains possible that the decline in star formation in green galaxies may be expedited by internal or external forces. However, there is no evidence that green galaxies have recently changed their star formation timescales relative to their previous longer term star formation histories., MNRAS, accepted

We report on the first ALMA observation of the CO(3$-$2) and rest-frame ~340 GHz continuum emission in PDS 456, which is the most luminous, radio-quiet QSO in the local Universe ($z$~0.18), with a bolometric luminosity $L_{\rm Bol}\sim10^{47}$ erg s$^{-1}$. ALMA angular resolution allowed us to map scales as small as ~700 pc. The molecular gas reservoir, traced by the core of the very bright CO(3$-$2) emission line, is distributed in a compact rotating disk, with size of ~1.3 kpc, seen close to face-on ($i$~25 deg). Fast CO(3$-$2) emission in the velocity range $v\in[-1000,+500]$ km s$^{-1}$ is also present. Specifically, we detect several blue-shifted clumps out to ~5 kpc from the nucleus, in addition to a compact ($R\lesssim1.2$ kpc), broad emission component. These components reveal a galaxy-wide molecular outflow, with a total mass $M_{\rm mol}^{\rm out}\sim2.5\times10^8$ $M_{\odot}$ and a mass outflow rate $\dot{M}_{\rm mol}\sim290$ $M_{\odot}$ yr$^{-1}$. The corresponding depletion time is ~8 Myr, shorter than the rate at which the molecular gas is converted into stars, indicating that the detected outflow is potentially able to quench star-formation in the host. The momentum flux of the molecular outflow normalised to the radiative momentum output (i.e. $L_{\rm Bol}/c$) is $\lesssim1$, comparable to that of the X-ray ultra-fast outflow (UFO) detected in PDS 456. This is at odds with the expectations for an energy-conserving expansion suggested for most of the large-scale outflows detected in low-luminosity AGN so far. We suggest three possible scenarios that may explain this observation: (i) in very luminous AGN such as our target the molecular gas phase is tracing only a fraction of the total outflowing mass; (ii) a small coupling between the shocked gas by the UFO and the host-galaxy ISM (iii) AGN radiation pressure may play an important role in driving the outflow., Accepted in A&A

[Context]: Cosmic reionization put an end to the dark ages that came after the recombination era. Observations seem to favor the scenario of massive-star photons generated in low-mass galaxies being responsible for the bulk of reionization and, whereas a possible contribution from AGN accretion disks has been widely considered, they are currently thought to have had a minor role in reionization. [Aims]: We aim to study the possibility of AGN having contributed to reionization not only through their accretion disks, but also through ionizing photons coming from the AGN jets interacting with the intergalactic medium. Methods. We adopt an empirically derived AGN luminosity function at z ≃ 6, use X-ray observations to correct it for the presence of obscured sources, and estimate the density of jetted AGN. We then use analytical calculations to derive the fraction of jet energy that goes into ionizing photons. Finally, we compute the contribution of AGN jets to the H II volume filling factor at redshifts z ≃ 15-5. [Results]: We show that the contribution of the AGN jet lobes to the reionization of the Universe at z ∼ 6 might have been as high as ? 10% of that of star-forming galaxies, under the most favorable conditions of jetted and obscuration fraction. [Conclusions]: The contribution of AGN to the reionization, while most likely not dominant, could have been higher than previously assumed, thanks to the radiation originated in the jet lobes., We acknowledge support by the Spanish Ministerio de Economía y Competitividad (MINECO/FEDER, UE) under grant AYA2016-76012-C3-1-P, with partial support by the European Regional Development Fund (ERDF/FEDER), MDM-2014-0369 of ICCUB (Unidad de Excelencia “María de Maeztu”), and the Catalan DEC Grant 2017 SGR 643. N. T.-A. acknowledges support from MINECO through FPU14/04887 Grant.

This thesis aims to enhance our understanding of galaxies by testing theoretical models of galaxy formation against observations, particularly in the cases of extreme systems which have been found to have an excess of baryonic mass in their central regions, in the form of either supermassive black holes or stellar populations, thus harbouring "monsters" in the deep. To this end we use the EAGLE project, a suite of cosmological, hydrodynamical simulations of galaxy formation and evolution that have been calibrated to reproduce the number density and sizes of galaxies in the Universe. We find that galaxies with supermassive black holes that are much more massive than expected given their stellar mass are predicted to exist and they become overmassive through early formation and/or tidal stripping from more massive galaxies. Recent evidence for excess stellar mass in the centres of high-mass, early-type galaxies has fueled claims that the stellar initial mass function (IMF) may be variable. We test the consequences of such variations in the EAGLE model by performing two additional simulations in which the IMF becomes respectively top-heavy or bottom-heavy in high-pressure environments. The strong effects of such variations are explored in terms of scaling relations between, and within, galaxies.

Cross-correlating the INTEGRAL/IBIS - Swift/BAT AGN population with radio catalogs (NVSS, FIRST, SUMSS), we found that 25% of extended radio sources are Giant Radio Galaxes (GRG), i.e. the largest individual objects in the Universe. This fraction is four time more abundant than what found in previous studies. In 2014, we observed a pilot sample of these soft-gamma ray selected GRG at low radio frequencies with the GMRT, with the aim of studying the morphological and spectral properties of these objects. Thanks to these data, we discovered the second X-shaped GRG to date, and a previously unidentified radio galaxy. Another object, observed both at kpc and pc scales (VLBI), showed an extreme jet re-orientation (about 90 degrees). Moreover, the majority of these objects show signs of restarting activity from previous observations in the literature. Given these intriguing premises, we embarked on a radio observing campaign, using both single dish (Effelsberg) and interferometers (VLBA), to probe the lifecycle of these soft gamma-ray selected GRG. The results of this campaign will be presented, that potentially shed light on the origin and evolution of the radio phase for this extreme class of objects (and radio-loud AGN in general), and the connection with high-energy emission. The X-ray properties, and in particular the correlation between the X-ray luminosity of the AGN and the radio luminosity of both the core and the lobes, will be discussed as well.

The reionization of the Universe ends the dark ages that started after the recombination era. In the case of H, reionization finishes around $z\sim 6$. Faint star-forming galaxies are the best candidate sources of the H-ionizing radiation, although active galactic nuclei may have also contributed. We have explored whether the termination regions of the jets from active galactic nuclei may have contributed significantly to the ionization of H in the late reionization epoch, around $z\sim 6-7$. We assumed that, as it has been proposed, active galactic nuclei at $z\sim 6$ may have presented a high jet fraction, accretion rate, and duty cycle, and that non-thermal electrons contribute significantly to the pressure of jet termination regions. Empirical black-hole mass functions were adopted to characterize the population of active galactic nuclei. From all this, estimates were derived for the isotropic H-ionizing radiation produced in the jet termination regions, at $z\sim 6$, through inverse Compton scattering off CMB photons. We find that the termination regions of the jets of active galactic nuclei may have radiated most of their energy in the form of H-ionizing radiation at $z\sim 6$. For typical black-hole mass functions at that redshift, under the considered conditions (long-lasting, common, and very active galactic nuclei with jets), the contribution of these jets to maintain (and possibly enhance) the ionization of H may have been non-negligible. We conclude that the termination regions of jets from active galactic nuclei could have had a significant role in the reionization of the Universe at $z\gtrsim 6$., Comment: Letter to the Editor accepted for publication in Astronomy & Astrophysics, very minor changes introduced

This thesis investigates how galaxies form and what diversifies the evolutionary histories of galaxies. The first part of this thesis describes the identification of luminous galaxies in the early Universe and the follow-up study of their properties with the Very Large Telescope, ALMA and the Hubble Space Telescope. Luminous galaxies are assembling through merging of multiple components and heavy elements as carbon are already in place relatively shortly after galaxies have formed. The second part describes the study of the Lyman-alpha escape fraction of galaxies at the peak of star formation history. The Lyman-alpha escape fraction is generally low, except for rare massive galaxies with AGN activity or for low mass galaxies. This implies that Lyman-alpha radiation escapes more efficiently in the early Universe, when galaxies tend to be less massive with a lower dust content. The final part of this thesis is a theoretical investigation of the co-evolution of dark matter halos and galaxies in the cosmological hydrodynamical EAGLE simulation. Galaxy stellar mass growth is driven by both the mass and formation time of dark matter halos. As a result, present-day growth rates of galaxies are coherent with the long time-scale histories.

This thesis investigates the structural evolution and assembly of galaxies since the first few billions years after the big bang. It makes use of the CANDELs and UVISTA galaxy surveys, the EAGLE hydrodynamical simulation as well as spectroscopy from XShooter on the VLT. Within this thesis I attempt to answer when stellar mass was assembled onto galaxies, where those stars were deposited as well as the physical mechanisms which underly that assembly.

We use ALMA and JVLA observations of the galaxy cluster Cl J1449+0856 at z=1.99, in order to study how dust-obscured star-formation, ISM content and AGN activity are linked to environment and galaxy interactions during the crucial phase of high-z cluster assembly. We present detections of multiple transitions of $^{12}$CO, as well as dust continuum emission detections from 11 galaxies in the core of Cl J1449+0856. We measure the gas excitation properties, star-formation rates, gas consumption timescales and gas-to-stellar mass ratios for the galaxies. We find evidence for a large fraction of galaxies with highly-excited molecular gas, contributing $>$50% to the total SFR in the cluster core. We compare these results with expectations for field galaxies, and conclude that environmental influences have strongly enhanced the fraction of excited galaxies in this cluster. We find a dearth of molecular gas in the galaxies' gas reservoirs, implying a high star-formation efficiency (SFE) in the cluster core, and find short gas depletion timescales $��$, 29 pages, 15 figures, 7 tables + Appendix. Accepted for publication in MNRAS

The galaxies found in optical surveys fall in two distinct regions of a diagram of optical colour versus absolute magnitude: the red sequence and the blue cloud, with the green valley in between. We show that the galaxies found in a submillimetre survey have almost the opposite distribution in this diagram, forming a ‘green mountain’. We show that these distinctive distributions follow naturally from a single, continuous, curved Galaxy Sequence in a diagram of specific star formation rate versus stellar mass, without there being the need for a separate star-forming galaxy main sequence and region of passive galaxies. The cause of the red sequence and the blue cloud is the geometric mapping between stellar mass/specific star formation rate and absolute magnitude/colour, which distorts a continuous Galaxy Sequence in the diagram of intrinsic properties into a bimodal distribution in the diagram of observed properties. The cause of the green mountain isMalmquist bias in the submillimetre waveband, with submillimetre surveys tending to select galaxies on the curve of the Galaxy Sequence, which have the highest ratios of submillimetre-to-optical luminosity. This effect, working in reverse, causes galaxies on the curve of the Galaxy Sequence to be underrepresented in optical samples, deepening the green valley. The green valley is therefore not evidence (1) for there being two distinct populations of galaxies, (2) for galaxies in this region evolving more quickly than galaxies in the blue cloud and the red sequence, and (3) for rapid-quenching processes in the galaxy population.

Gas stripping of spiral galaxies or mergers are thought to be the formation mechanisms of lenticular galaxies. In order to determine the conditions in which each scenario dominates, we derive stellar populations of both the bulge and disk regions of 279 lenticular galaxies in the MaNGA survey. We find a clear bimodality in stellar age and metallicity within the population of S0s and this is strongly correlated with stellar mass. Old and metal-rich bulges and disks belong to massive galaxies, and young and metal-poor bulges and disks are hosted by low-mass galaxies. From this we conclude that the bulges and disks are co-evolving. When the bulge and disk stellar ages are compared, we find that the bulge is almost always older than the disk for massive galaxies ($\textrm{M}_{\star} > 10^{10}~\textrm{M}_{\odot}$). The opposite is true for lower mass galaxies. We conclude that we see two separate populations of lenticular galaxies. The old, massive, and metal-rich population possess bulges that are predominantly older than their disks, which we speculate may have been caused by morphological or inside-out quenching. In contrast, the less massive and more metal-poor population have bulges with more recent star formation than their disks. We postulate they may be undergoing bulge rejuvenation (or disk fading), or compaction. Environment doesn't play a distinct role in the properties of either population. Our findings give weight to the notion that while the faded spiral scenario likely formed low-mass S0s, other processes, such as mergers, may be responsible for high-mass S0s., 15 pages, 10 figures. Accepted for publication in MNRAS