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Book Galaxy Populations in Rich Environments

Download or read book Galaxy Populations in Rich Environments written by Kim-Vy Huu Tran and published by . This book was released on 2002 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Properties and Evolution of Galaxy Populations in the Rich Cluster Environment

Download or read book The Properties and Evolution of Galaxy Populations in the Rich Cluster Environment written by Michael Benjamin Pracy and published by . This book was released on 2006 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Galaxy Populations in Rich Environments

Download or read book Galaxy Populations in Rich Environments written by Kim-Vy Huu Tran and published by . This book was released on 2002 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Galaxy Evolution in Groups and Clusters

Download or read book Galaxy Evolution in Groups and Clusters written by Catarina Lobo and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxy groups and clusters provide excellent laboratories for studying galaxy properties in different environments and at different look-back times. In particular, the recent detections of high-redshift cluster candidates, only possible with the current high-technology instrumentation, add a new dimension to the problem. Along with the ever increasing computing power and sophisticated algorithms to model clusters of galaxies, it may help us to understand the origins of today's groups and clusters, as well as of their member galaxies. These workshop proceedings provide a snapshot of the current research in this subject, covering the observations, theory and numerical simulations relevant to galaxy evolution in groups and clusters. In this book, intended primarily to researchers in the field, particular emphasis is given to the recent impressive progress in the field, on important new results, and on the future prospects and open questions to be tackled.

Book The Cluster Environments of Distant Radio Galaxies

Download or read book The Cluster Environments of Distant Radio Galaxies written by Mark Dickinson and published by . This book was released on 1994 with total page 586 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Relative populations of rich spherical clusters of galaxies

Download or read book Relative populations of rich spherical clusters of galaxies written by Fritz Zwicky and published by . This book was released on 1956 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Environment and the Formation of Galaxies

Download or read book Environment and the Formation of Galaxies written by Ignacio Ferreras and published by . This book was released on 2011-07-07 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Group Galaxy Population Through the Cosmic Time

Download or read book The Group Galaxy Population Through the Cosmic Time written by Ghazaleh Erfanianfar and published by . This book was released on 2014 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Environmental Quantification and H   Characterisation of the Most Isolated Galaxies in the Local Universe

Download or read book Environmental Quantification and H Characterisation of the Most Isolated Galaxies in the Local Universe written by Simon Verley and published by . This book was released on 2005 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: Le rôle de l'environnement sur l'évolution des galaxies n'est pas encore entièrement connu. Pour quantifier les rôles joués par les processus externes, on doit identifier un échantillon de galaxies isolées. Nous avons étudié 950 galaxies en provenance du Catalogue de Galaxies isolées et évalué leur isolation. Nous avons défini, comparé et discuté différents critères pour quantifier le degré d'isolation de ces galaxies, comme la densité de surface locale, l'estimation des forces de marées externes affectant chaque galaxie isolée. De plus nous avons cherché les redshifts des galaxies centrales ainsi que ceux de leurs compagnons pour avoir une image en trois dimensions de l'environnement. Enfin, nous avons appliqué nos procédures aux triplets, groupes compacts et amas de galaxies et interprété la population de galaxies isolées à la lumière de ces échantillons de contrôle. La formation d'étoiles est connue pour être affectée par l'environnement local des galaxies mais le taux de formation d'étoiles dépend aussi des caractéristiques intrinsèques du milieu interstellaire. Nous avons observé et compilé des données photométriques pour 200 galaxies spirales isolées. Ensuite, nous avons étudié l'aspect de la morphologie en H alpha des 45 galaxies les plus grandes et les moins inclinées. En utilisant les techniques de Transformation de Fourier Rapide, nous nous focalisons sur les modes des bras spiraux. Nous quantifions la force des barres et nous donnons les couples entre les étoiles nouvellement formées et la matière optique. La fréquence observée des modèles morphologiques particuliers apporte des contraintes sur la durée de vie des barres, et les temps de destruction associés.

Book Environmental Influences on Dwarf Galaxy Evolution

Download or read book Environmental Influences on Dwarf Galaxy Evolution written by Sabrina Renee Stierwalt and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxy groups are a rich source of information concerning galaxy evolution as they represent a fundamental link between individual galaxies and large scale structures. Nearby groups probe the low end of the galaxy mass function for the dwarf systems that constitute the most numerous extragalactic population in the local universe [Karachentsev et al., 2004]. Inspired by recent progress in our understanding of the Local Group, this dissertation addresses how much of this knowledge can be applied to other nearby groups by focusing on the Leo I Group at 11 Mpc. Gas-deficient, early-type dwarfs dominate the Local Group (Mateo [1998]; Belokurov et al. [2007]), but a few faint, HI-bearing dwarfs have been discovered in the outskirts of the Milky Way's influence (e.g. Leo T; Irwin et al. [2007]). We use the wide areal coverage of the Arecibo Legacy Fast ALFA (ALFALFA) HI survey to search the full extent of Leo I and exploit the survey's superior sensitivity, spatial and spectral resolution to probe lower HI masses than previous HI surveys. ALFALFA finds in Leo I a significant population of low surface brightness dwarfs missed by optical surveys which suggests similar systems in the Local Group may represent a so far poorly studied population of widely distributed, optically faint yet gas-bearing dwarfs. The morphological segregation seen in the Local Group is also reflected in Leo I and further suggests a significant population of gas-bearing dwarfs may be missed by surveys narrowly focused around more massive systems. The Leo I HI mass function is dominated by low mass objects yielding a steeper low-mass slope than found for luminosity functions of the group. However, the slope still falls short of that predicted by simulations of structure formation. Further contributors to this gap may be dwarf systems formed from tidal material (TDGs), the fraction of which, even in the Local Group, remains unknown. We find that TDGs can be identified from the ALFALFA survey based on their proximity to tidal remnants and from optical spectroscopic followup via their high gas fractions and high metallicities given their luminosities. However, despite the two large tidal remnants found in Leo I, our search results in only two TDGs for the group. If most dwarfs are instead formed from small dark matter haloes as suggested by the [LAMDA]CDM framework, different classes of dwarf may reflect early versus late stages of evolution. Dwarfs of mixed morphologies, like the six so-called transition dwarfs in the Local Group, may represent the evolutionary link between gas-rich and gas-poor classes, but when constrained by the requirement of HII regions, we find only one such candidate in Leo I. The work presented here lays the groundwork for future HI-based group studies which will be made possible with rich ALFALFA dataset.

Book Evolution of Dwarf Galaxy Properties in Local Group Environments

Download or read book Evolution of Dwarf Galaxy Properties in Local Group Environments written by Kenza Sigrid Arraki and published by . This book was released on 2016 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding galaxy evolution depends on connecting large-scale structures determined by the [Lambda]CDM model with, at minimum, the small-scale physics of gas, star formation, and stellar feedback. Formation of galaxies within dark matter halos is sensitive to the physical phenomena occurring within and around the halo. This is especially true for dwarf galaxies, which have smaller potential wells and are more susceptible to the effects of tidal stripping and gas ionization and removal than larger galaxies. At dwarf galaxies scales comparisons of dark matter-only simulations with observations has unveiled various differences such as the core-cusp, the missing satellites, and the too big to fail problems. We have run suites of collisionless and hydrodynamical simulations of dwarf galaxies evolution in massive host environments to address these issues. We performed controlled, numerical simulations, which mimic the effects of baryons, in order to examine the assumptions implicitly made by dark matter-only simulations. The too big to fail problem is due to the overabundance of relatively massive, dense satellite galaxies found in simulations of Milky Way-like environments. We found that the removal of a small baryonic component from the central region of forming dwarf spheroidal galaxies and the inclusion of a disk component in the host galaxy can substantially reduce the central dark matter density of satellites, bringing simulations and observations of satellites into agreement. Additionally, we studied hydrodynamical simulations of massive host galaxies and their surrounding dwarf galaxy populations. The VELA simulation suite of cosmological zoom-in simulations is run with the ART code, stochastic star formation, and stellar feedback (supernovae feedback, stellar winds, radiation pressure, and photoionization pressure). The suite includes host galaxies with M[subscript vir](z = 0 ) = 1011 - 1012 M[sol] and their satellite dwarf galaxies and local isolated dwarf galaxies around each primary galaxy. We found that the inclusion of these relevant physical processes aligned the velocity functions and star formation histories of the dwarf galaxy populations closer to observations of the Local Group dwarf galaxies. By reproducing observations of dwarf galaxies we show how the inclusion of baryons in simulations relieves many of the discovered tensions between dark matter-only simulations and observations.

Book Toward a New Level of Modeling of Environmental Effects on Galaxies

Download or read book Toward a New Level of Modeling of Environmental Effects on Galaxies written by Manuel Duarte and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies lie in a large panel of environments from isolated galaxies, to pairs, groups or clusters. The environment is expected to have an impact on galaxy properties such as morphology, stellar formation, metallicity\ldots. Some studies already tried to quantify the importance of the global environment (linked to the dark matter halo mass) and the local environment (galaxy position in the group). These studies have shown that the environment plays a minor role except for low mass galaxies. But the quantification of the environment is difficult since detected groups in redshift space (the only one accessible by the observer) are very elongated, making it difficult to extract spherical groups in real space. If these quantification errors are too important, environment effects will not be measured correctly. Moreover, other physical processes are at work inside groups whose relative roles are not well understood. For example, major or minor mergers (rich or poor in gas, between satellite galaxies, or after the decay of the orbit of a satellite onto the central galaxy by dynamical friction), rapid flybys harassing galaxies, stripping of the interstellar gas by ram pressure or of the gaseous reservoir by tidal forces. Although semi-analytical codes of galaxy formation from initial conditions of a LambdaCDM Universe fit well a large set of observed relations, there are still some discrepancies that might be possibly explained by a lack of correct physical recipes of environmental effects in these models. Our goal with this thesis is to have a detailed comprehension of the role of environment on galaxy properties, and finally determine the major physical processes in the modulation of these properties with both local and global environment. For this, an optimal extraction of galaxy groups from the projected phase space is necessary. We performed a study and re-implementation of some existing group finder to estimate their strengths and weaknesses in the detection of galaxy groups. A galaxy mock catalogue in redshift space, designed to mimic the primary spectroscopic sample of the SDSS survey was created to apply several galaxy group algorithms. An advantage is the already known membership that we can compare to galaxy groups extracted from redshift space. Semi-analytical codes of galaxy formation give us such galaxy catalogs we transformed to be coherent with the vision of an observer. With these mock catalogues, we tested the very popular Friends-of-Friends grouping algorithm. We determined the optimal linking lengths against the set of tests and optimal criterion we developed to judge the efficiency of an algorithm. It appears that this choice of linking lengths depends on the scientific goal to do with the group catalogue. A large part of the thesis consisted on the realization of a new grouping algorithm called MAGGIE (Models and Algorithm for Galaxy Groups, Interlopers and Environment), Bayesian and probabilistic. MAGGIE uses our priors acquired with analysis of cosmological simulations for large scale structure and of observations obtained from large galaxy surveys, to better constrain the selection of galaxy groups from redshift space. Comparison of MAGGIE with the FoF algorithm shows that MAGGIE is superior in avoiding the fragmentation of real space groups, the membership selection (completeness, reliability) and in the group properties (group mass, luminosity). The better performance of MAGGIE comes from its probabilistic nature, the use of astrophysical and cosmological priors, and the use of halo abundance matching technique linking central galaxy distributions (stellar mass or luminosity) to physical properties of dark matter halos. The future application of MAGGIE on galaxy surveys such as the Sloan Digital Sky Survey or the deeper Galaxy and Mass Assembly, taking care of their own observational problems, should improve our understanding of the modulation of galaxy properties with their global and local environments and physical processes operating inside galaxy groups.

Book The Influence of Environment on High redshift Cluster Galaxies

Download or read book The Influence of Environment on High redshift Cluster Galaxies written by Anna Delahaye and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Galaxy properties such as colour, star-formation rate, and morphology are influenced by the environments in which they reside. In particular, the environments of galaxy clusters have been shown be very efficient at quenching star-formation and altering other observed galactic properties, although the specific mechanisms responsible for this evolution are not fully understood. Additionally, the effect that the cluster environment has on galaxies does not appear to be consistent at all redshifts, with high-redshift cluster galaxies having different observed properties compared to their local counterparts. In this thesis, two studies are presented that investigate the role of high-redshift galaxy cluster environments on their galactic populations.The first study is an extensive photometric survey of the supercluster RCS2319+00, a massive supercluster system comprising three virialized cluster cores in close proximity with one another in projected space as well as redshift space. The system is located at a redshift of z = 0.9 and is expected to merge into a single 10^15 solar mass cluster by z = 0.5, and is therefore a progenitor of the most massive cluster systems we see in the nearby universe today. Spectroscopic and submillimetre surveys have previously uncovered a complicated system of filamentary structure and infalling groups. To complement the previous studies, we assemble a large multiwavelength catalogue to identify cluster members based on photometric properties.With a photometric catalogue complete with photometric redshifts for over 16,000 objects across the central RCS2319 field, we compile a cluster catalogue of nearly 1,800 cluster members. Using proxies for both local and global environments, we investigate the mass and colour properties of cluster galaxies depending on their specific environments within the supercluster. While we do not find a strong dependence on global environment, we do recover both a mass-density and colour-density relation depending on the local overdensity suggesting that immediate surroundings influence galactic properties more strongly than the overall structure in which it resides.The second study presented investigates the presence of merging systems in high-redshift cluster environments compared to the field. We use a sample of four galaxy clusters (1.59

Book Galaxy Transformation Under Extreme Conditions

Download or read book Galaxy Transformation Under Extreme Conditions written by Brian Clark Lemaux and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes research performed in the field of observational astrophysics as part of the Observations of Redshift Evolution in Large Scale Environment (ORELSE) survey. The general motivation of the research presented in this dissertation is to investigate the processes responsible for the evolution of galaxies in a wide range of physical conditions over cosmic time. Throughout this dissertation, galaxy populations will be considered in the very nearby universe (i.e., within one billion light years from Earth), the middle-aged universe (i.e., eight billion years ago), and in the very early universe (i.e., just one billion years after the beginning of the universe). In each chapter I present unique data from observations taken and analyzed specifically for the ORELSE survey. In the first part of this dissertation I describe the context, aims, and current state of the ORELSE survey. The studies presented in this dissertation span a large range of galaxy samples and investigate a variety of different astrophysical phenomena. As all of these studies fall under the context of galaxy evolution, these initial sections will set the framework for the variety of studies presented in this thesis. In the second part of this dissertation I present four studies undertaken to investigate various aspects of galaxy evolution. The first of these studies is an investigation of a large population of very distant galaxies detected in one of the ORELSE fields. The survey in this field represents the deepest survey of a particular kind of very distant galaxy population known as Lyman[alpha] Emitter (LAEs). The number of LAEs found in this survey far exceeded expectations for such galaxies and are shown to be in excess of every other survey of similar galaxies at similar distances. This result has important consequences for galaxy evolution studies, as it suggests that faint LAEs may be much more numerous than previously thought. This work also has important consequences for a process in the early universe known as reionization, which is the subject of much debate amongst astronomers. The second and third of these studies are investigations using near-infrared spectroscopy of X-ray bright and red galaxies that exhibit optical spectra with prominent emission features. These studies are the first systematic investigations of both galaxy populations in the middle-aged universe using near-infrared spectroscopy. In both studies I conclude the dominant mechanism giving rise to optical emission line features are processes associated with the presence of an Active Galactic Nuclei (AGN) rather than normal star formation. This result has important consequences for galaxy evolutionary scenarios, as the two processes are typically difficult to separate observationally and are thought to be related. The final study in this presentation is a full investigation of the processes driving galaxy evolution in one of the ORELSE fields, the Cl1604 supercluster. In this study I present the wealth of astronomical observations available to the ORELSE survey on the member galaxies of this supercluster. Several transitional populations of galaxies are detected in the supercluster environment, and their properties are analyzed in the context of galaxy evolution. Processing of the galaxy population is found to be significant in both the densest environments in the supercluster and the lower-density regions. One of the major conclusions of this work relates to the efficiency of these transformative processes and the global environment in which a galaxy resides. I present evidence for a process termed "dynamical downsizing", in which efficient transforming of galaxies occurs earliest in structures of galaxies that are observed to be relaxed (i.e., virialized) in their dynamics.

Book Mass Dependent Galaxy Transformation Mechanisms in the Complex Environment of SuperGroup Abell 1882

Download or read book Mass Dependent Galaxy Transformation Mechanisms in the Complex Environment of SuperGroup Abell 1882 written by Aparajita Sengupta and published by . This book was released on 2013 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present our data and results from panchromatic photometry and optical spectrometry of the nearest (extremely rich) filamentary large scale structure, SuperGroup Abell 1882. It is a precursor of a cluster and is an inevitable part of the narrative in the study of galaxy transformations. There has been strong empirical evidence over the past three decades that galaxy environment affects galaxy properties. Blue disky galaxies transform into red bulge-like galaxies as they traverse into the deeper recesses of a cluster. However, we have little insight into the story of galaxy evolution in the early stages of cluster formation. Besides, in relaxed clusters that have been studied extensively, several evolutionary mechanisms take effect on similar spatial and temporal scales, making it almost impossible to disentangle different local and global mechanisms. A SuperGroup on the other hand, has a shallower dark-matter potential. Here, the accreting galaxies are subjected to evolutionary mechanisms over larger time and spatial scales. This separates processes that are otherwise superimposed in rich cluster-filament interfaces. As has been found from cluster studies, galaxy color and morphology tie very strongly with local galaxy density even in a complex and nascent structure like Abell 1882. Our major results indicate that there is a strong dependence of galaxy transformations on the galaxy masses themselves. Mass- dependent evolutionary mechanisms affect galaxies at different spatial scales. The galaxy color also varies with radial projected distance from the assumed center of the structure for a constant local galaxy density, indicating the underlying large scale structure as a second order evolutionary driver. We have looked for clues to the types of mechanisms that might cause the transformations at various mass regimes. We have found the thoroughly quenched low mass galaxies confined to the groups, whereas there are evidences of intermediate-mass quenched galaxies even in the far outskirts. However, unlike what we observe in this system, ideally would we expect the dwarf galaxies with their shallow potentials to be more vulnerable than more massive galaxies, and hence be quenched earlier. We propose harassment and/or ram-pressure stripping as the mechanism that might lead to the quenched galaxies near or inside the high density, high velocity dispersion region in and near the groups; and mergers as the mechanism for the intermediate mass quenched galaxies at the low density, low velocity dispersion outskirts. We also identify a starburst population preferentially occurring within the filaments, at least a subset of which must be progenitors of the quenched galaxies at the core of Abell 1882. This also indicates a higher degree of preprocessing within the filaments as compared to that of the field.

Book Observations and Modeling of Merging Galaxy Clusters

Download or read book Observations and Modeling of Merging Galaxy Clusters written by Nathan Ryan Golovich and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Context: Galaxy clusters grow hierarchically with continuous accretion bookended by major merging events that release immense gravitational potential energy (as much as ~1065 erg). This energy creates an environment for rich astrophysics. Precise measurements of the dark matter halo, intra-cluster medium, and galaxy population have resulted in a number of important results including dark matter constraints and explanations of the generation of cosmic rays. However, since the timescale of major mergers (~several Gyr) relegates observations of individual systems to mere snapshots, these results are difficult to understand under a consistent dynamical framework. While computationally expensive simulations are vital in this regard, the vastness of parameter space has necessitated simulations of idealized mergers that are unlikely to capture the full richness. Merger speeds, geometries, and timescales each have a profound consequential effect, but even these simple dynamical properties of the mergers are often poorly understood. A method to identify and constrain the best systems for probing the rich astrophysics of merging clusters is needed. Such a method could then be utilized to prioritize observational follow up and best inform proper exploration of dynamical phase space. Task: In order to identify and model a large number of systems, in this dissertation, we compile an ensemble of major mergers each containing radio relics. We then complete a pan-chromatic study of these 29 systems including wide field optical photometry, targeted optical spectroscopy of member galaxies, radio, and X-ray observations. We use the optical observations to model the galaxy substructure and estimate line of sight motion. In conjunction with the radio and X-ray data, these substructure models helped elucidate the most likely merger scenario for each system and further constrain the dynamical properties of each system. We demonstrate the power of this technique through detailed analyses of two individual merging clusters. Each are largely bimodal mergers occurring in the plane of the sky. We build on the dynamical analyses of Dawson (2013b) and Ng et al. (2015) in order to constrain the merger speeds, timescales, and geometry for these two systems, which are among a gold sample earmarked for further follow up. Findings: MACS J1149.5+2223 has a previously unidentified southern subcluster involved in a major merger with the well-studied northern subcluster. We confirm the system to be among the most massive clusters known, and we study the dynamics of the merger. MACS J1149.5+2223 appears to be a more evolved system than the Bullet Cluster observed near apocenter. ZwCl 0008.8+5215 is a less massive but a bimodal system with two radio relics and a cool-core "bullet'' analogous to the namesake of the Bullet Cluster. These two systems occupy different regions of merger phase space with the pericentric relative velocities of ~2800 km s−1 and ~1800 km s−1 for MACS J1149.5+2223 and ZwCl 0008.8+5215, respectively. The time since pericenter for the observed states are ~1.2 Gyr and ~0.8 Gyr, respectively. In the ensemble analysis, we confirm that radio relic selection is an efficient trigger for the identification of major mergers. In particular, 28 of the 29 systems exhibit galaxy substructure aligned with the radio relics and the disturbed intra-cluster medium. Radio relics are typically aligned within 20° of the axis connecting the two galaxy subclusters. Furthermore, when radio relics are aligned with substructure, the line of sight velocity difference between the two subclusters is small compared with the infall velocity. This strongly implies radio relic selection is an efficient selector of systems merging in the plane of the sky. While many of the systems are complex with several simultaneous merging subclusters, these systems generally only contain one radio relic. Systems with double radio relics uniformly suggest major mergers with two dominant substructures well aligned between the radio relics. Conclusions: Radio relics are efficient triggers for identifying major mergers occurring within the plane of the sky. This is ideal for observing offsets between galaxies and dark matter distributions as well as cluster shocks. Double radio relic systems, in particular, have the simplest geometries, which allow for accurate dynamical models and inferred astrophysics. Comparing and contrasting the dynamical models of MACS J1149.5+2223 and ZwCl 0008.8+5215 with similar studies in the literature (Dawsonm 2013b; Ng et al., 2015; vam Weeren et al., 2017), a wide range of dynamical phase space ~1500-3000 km s−1 at pericenter and ~500-1500 Myr after pericenter) may be sampled with radio relic mergers. With sufficient samples of bimodal systems, velocity dependence of underlying astrophysics may be uncovered. Perspectives: With the gold sample identified from our ensemble analysis, our photometric observations will be used to constrain the dark matter distribution with gravitational lensing (in studies analogous to Jee et al., 2015, 2016). Furthermore, as new radio surveys identify additional radio relic systems, more may be added to this gold sample. These systems are best served to test self-interacting dark matter hypotheses, but observational based models much be complimented with detailed simulations, and in order to move forward with this work, more realistic initial conditions based on observations must be utilized. Collaborators and I are actively studying existing cosmological N-body simulations in search of analogs to these systems, which may then be re-simulated at higher resolution with new physics included.

Book Constraints on Environmental and Secular Effects on the Chemodynamical Evolution of Dwarf Galaxies

Download or read book Constraints on Environmental and Secular Effects on the Chemodynamical Evolution of Dwarf Galaxies written by Ryan Leaman and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents observations and analysis relating to the understanding of processes that govern the formation and evolution of low mass galactic systems. In particular we have focused on separating out the contribution to the chemical and dynamical evolution of dwarf galaxies due to solely secular (internal) processes compared to external effects from the local environment a galaxy resides in. Our observational data focus on an extremely isolated dwarf galaxy, WLM, which we demonstrate has had a uniquely quiescent tidal history, thereby making it an excellent test case for such a study. With spectroscopic and photometric observations of the resolved stars and neutral gas in WLM we have been able to characterize the chemical, structural and kinematic properties of this gas rich dwarf galaxy. As WLM has not been subject to strong tidal or ram-pressure stripping of its stellar and gaseous populations, we have been able to compare the dynamical evolution and chemical history of WLM to theoretical models which are environment independent. A differential comparison of WLM to more environmentally processed dwarf galaxies in the Local Group has revealed that WLM's structural and dynamical state is far from the idealized picture of dIrrs as thin gas-rich rotating systems. The stellar component of WLM shows equal parts rotation and dispersion, and both the gaseous and stellar structural properties show an intrinsically thick axisymmetric configuration. The time evolution of the random (dispersion) component of the stellar orbital energy shows an increase with stellar age, which we show is consistent with secular processes alone - such as disk heating from giant molecular clouds and dark matter substructure. While the degree to which the thick structural and dynamically hot configuration for WLM is surprising, its chemical properties show remarkably consistent values with other galaxies of the same halo mass. Comparing the spatial chemical trends in WLM with other dwarf galaxies we identify a correlation between the strength of the radial abundance gradients and the angular momentum content of dwarf galaxies in the Local Group. Finally using a large sample of chemical abundance measurements in the literature for dwarf galaxies and star clusters, we demonstrate that their distributions of chemical elements all exhibit a binomial form, and use the statistical properties of the distributions to identify a new metric for differentiating low luminosity stellar systems. We further apply a simple binomial chemical evolution model to describe the self-enrichment and pre-enrichment in the two classes of objects, and suggest how this may be used to place constraints on the formation environments of globular clusters in particular.