Download or read book Characterising the Effect of Environment on Galaxy Evolution written by E. Kukstas and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Cosmic Web and the Role of Environment in Galaxy Evolution written by Ryan Cybulski and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Universe, on extra-galactic scales, is composed of a vast network of structures dubbed the "cosmic web". One of the most fundamental discoveries about the evolution of galaxies is that their properties have a dependence on their location relative to this cosmic web (i.e., their environment). However, detailed studies of the environmental dependence on galaxy evolution have been extremely challenging due to the inherent complexity of the structures on the largest scales, a plethora of techniques being used to try to map the cosmic web, and other confounding factors, such as the masses of galaxies, that also affect their evolution. In this work, we will present a technique for characterizing the environments of galaxies in the cosmic web, which is comprised of two separate, but complementary, methods that together provide a more complete measure of environment. After some introductory background in Chapter 1, we will demonstrate these mapping techniques on the Coma Supercluster, and present an analysis of the star-formation activity of about 4,000 galaxies in the supercluster environment in Chapter 2. Next, in Chapter 3 we present a greatly expanded application of our mapping techniques encompassing about 60,000 galaxies within 200 Mpc that addresses several outstanding questions from the Coma Supercluster study, and also leads to new intriguing insights into the evolution of galaxies as a function of environment. Then, in Chapter 4 we present a pilot study focusing on galaxy evolution as traced by the gas content around two galaxy clusters. We also expand upon this pilot study in Chapter 5, whereupon we examine more closely the resiliency of molecular gas content, compared to the atomic gas, to the effects of the cluster environment. And finally, in Chapter 6 we present some concluding remarks and explore some promising avenues for future study.
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.
Download or read book The Impact of Environment on Galaxy Evolution written by Rosemary Theresa Coogan and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Evolution of Galaxy Activity in Massive Clusters written by Emil S Noordeh and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The nature of galaxy evolution from the early Universe to the present day is intricately linked to large-scale environment: the environments of galaxies are expected to play a critical role in the development of their morphologies, star formation activity, and the activity of their central Super Massive Black Holes (SMBHs). Large scale environment can strongly and rapidly affect gas reservoirs which are a prerequisite for both star formation and SMBH activity. We would expect the effect of environment to be most pronounced in massive galaxy clusters, where both the density of the intracluster medium and number density of galaxies are the highest. This has indeed been established for star formation activity in the local and intermediate redshift universe, where dense, cluster environments are more likely to host elliptical, quiescent galaxies. However, the impact of the cluster environment on SMBH activity has been significantly less clear. At high redshift, the impact of clusters on galaxy activity is even less well understood. This is due to both a decline in the number of massive clusters at high redshift as well as increasing observational difficulty in reliably identifying and characterizing both the clusters themselves and their member galaxies. This dissertation tries to bring some clarity to these unknowns. First, we present an analysis of SMBH activity in a sample of massive clusters at intermediate redshift where we confirm a dependence of this activity on cluster mass. Second, we describe the spectroscopic characterization of one of the highest redshift galaxy clusters ever discovered, existing at a lookback time of more than 10 billion years. We model the stellar population of its member galaxies and trace their formation back to the cosmic dark ages, when the Universe was only 370 million years old. Finally, we do a deep dive into this cluster's galaxy population and find it to be remarkably similar to that of clusters in the local universe. We identify a tremendously enhanced quiescent fraction relative to the field and find evidence for accelerated size-evolution in these quiescent galaxies.
Download or read book Feedback and Environmental Effect on Star Formation in Galaxies written by Taro Sato and published by ProQuest. This book was released on 2007 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent studies of galaxy evolution and formation have shown that both environment and gaseous "feedback" process are critical factors that give rise to the observed variety and richness in galaxy populations. This thesis presents research in these two seemingly disparate aspects of galaxy formation. One deals with a detailed study of the star-forming galaxy population in z = 0.4 galaxy cluster Abell 851, which describes how they may be the key population at an intermediate phase of environmentally-driven evolution, causing the Butcher-Oemler effect. The other is a study of host galaxies of gaseous outflows which are drawn from a large-scale galaxy survey. The census shows that starburst-driven outflows are ubiquitous in the galaxies in transition, suggesting the importance of feedback-driven evolution. We speculate on how these factors might play synergetic or even integral roles in transforming the star-forming property of galaxy, and propose a few directions of research that may help elucidate the significance of feedback and environment in galaxy formation and evolution.
Download or read book A Comparison of the Effects of Local and Global Environment on Galaxy Evolution in Low Redshift Galaxy Clusters written by Brittany Howard and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of the Environment on the Evolution of Galaxy Colours written by and published by . This book was released on 2006 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Influence of Environment on Galaxy Evolution written by Dennis William Just and published by . This book was released on 2012 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galaxy Formation and Evolution written by Houjun Mo and published by Cambridge University Press. This book was released on 2010-05-20 with total page 841 pages. Available in PDF, EPUB and Kindle. Book excerpt: A coherent introduction for researchers in astronomy, particle physics, and cosmology on the formation and evolution of galaxies.
Download or read book The Properties of Barred Disks in the Field and Dense Environments written by Irina Stoilova Marinova and published by . This book was released on 2011 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stellar bars are the most important internal drivers of the evolution of disk galaxies because they efficiently redistribute mass and angular momentum in the baryonic and dark matter components of galaxies. Mounting evidence suggests that mechanisms other than major mergers of galaxies, such as minor mergers, gas accretion, and bar-driven secular processes, play an important role in galaxy evolution since a redshift z~2. In order to characterize the evolution of barred disks, this thesis presents one of the most comprehensive studies of barred galaxies in the field at low redshifts, and also as a function of environment across galaxy clusters of different densities. This work improves significantly on earlier studies by using quantitative methods to characterize bars, analyzing high-quality data from some of the largest disk galaxy samples to date, and using results across a range of Hubble types and environments to test different theoretical models for the evolution of disk galaxies. Our main results are summarized below: (1) Studies done as a part of this thesis have quantitatively shown for the first time that the optical bar fraction in z~ 0 field galaxies is a sensitive and non-monotonic function of host galaxy properties, such as the luminosity, stellar mass, and bulge-to-disk ratio. We find that at z~0, the bar fraction increases significantly from galaxies of intermediate mass and Hubble types (Sb) toward those of lower mass and late Hubble types (Sd-Sm). The behavior from intermediate to early Hubble types is more uncertain. These results, which have been subsequently confirmed by independent studies, set constraints for theoretical models and in particular underline the importance for bar growth of angular momentum exchange between the bar, disk, bulge, and dark matter halo, as well as the possible triggering of bars by external satellites and interactions with the dark matter. Furthermore, our results at optical and near-infrared wavelengths on the fraction and sizes of bars at z~0 provide the zero-redshift anchor point for studies of bars at higher redshifts with current and future space missions (e.g., ACS, WFC3, JWST), and allow us to assess the systematic effects in such studies. (2) Although cluster environments are unique laboratories for investigating the evolution of barred disks, only sparse and disparate results have emerged from early studies. In this thesis, we study barred disks in clusters using high-quality data from the Hubble Space Telescope Advanced Camera for Surveys for the moderately-rich cluster Abell 901/902 (characterized by a galaxy number density n~1,000 gal Mpc−3) at z~0.165, and of the Coma cluster at z~0.02, the densest cluster (n~10,000 gal Mpc−3) in the nearby Universe. We find that the optical bar fraction for bright, early Hubble type disk galaxies does not show a statistically significant variation (within the error bars of ± 10 to 12%) as a function of galaxy environment within the Abell 901/902 cluster, as well as between the Abell 901/902 cluster and the field. Similarly, the optical bar fraction for bright S0 galaxies shows no statistically significant variation (within the error bars of ±10%) between the Virgo, Abell 901/902, and core of the Coma clusters, even though these environments span over an order of magnitude in galaxy number density (n~300 to 10,000 gal Mpc−3). We suggest that the S0 bar fraction is not greatly enhanced in denser environments, such as the core of Coma, due to the predominance of high speed encounters over slow ones, the tidal heating of S0 disks, and the low gas content of S0s in rich clusters.
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.
Download or read book The Effect of Environment on the Formation and Evolution of Galaxies in the Distant Universe written by Robert W. Chuter and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis I primarily use the UKIDSS Ultra-Deep Survey (UDS) to investigate the effect environment has on galaxies across the redshift range 0.25 z
Download or read book Observational Evidence of the Large scale Environmental Influence on Dwarf Galaxy Evolution written by Kelly Ann Douglass and published by . This book was released on 2017 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigate how the cosmic environment affects galaxy evolution in the Universe by studying gas-phase chemical abundances and other galaxy properties as a function of the large-scale environment and local density of galaxies. Using spectroscopic observations from the Sloan Digital Sky Survey Data Release 7, we estimate the oxygen and nitrogen abundances of 993 star-forming void dwarf galaxies and 759 star-forming dwarf galaxies in denser regions. We use the Direct Te method for calculating the gas-phase chemical abundances in the dwarf galaxies because it is best suited for low metallicity, low mass galaxies. A substitute for the [OII] 3727 doublet is developed, permitting oxygen abundance estimates of SDSS dwarf galaxies at all redshifts with the Direct Te method. We find that star-forming void dwarf galaxies have slightly higher oxygen abundances than star-forming dwarf galaxies in denser environments, but we find that void dwarf galaxies have slightly lower nitrogen abundances and lower N/O ratios than galaxies in denser regions. At smaller scales, we find that only the presence of a neighboring galaxy within 0.05 Mpc/h or 0.1 r_virial, or the presence of a group within 0.05 Mpc/h, influences a dwarf galaxy's evolution. Dwarf galaxies within 0.05 Mpc/h or 0.1 r_virial of another galaxy tend to be bluer, have higher sSFRs, have higher oxygen abundances, and have lower N/O ratios than average. In contrast, galaxies within 0.05 Mpc/h of the center of the closest group have lower oxygen and nitrogen abundances than average. We also investigate how a galaxy transitions through the color-magnitude diagram, evolving from a blue, star-forming spiral or irregular galaxy in the blue sequence to a red elliptical galaxy in the red cloud through the green valley. We discover that combining a galaxy's color, color gradient, and inverse concentration index determines a galaxy's location on the color-magnitude diagram. The results indicate that, in the green valley, there is a lower fraction of void dwarf galaxies than dwarf galaxies in denser regions. From these analyses, we surmise that void dwarf galaxies experience delayed star formation as predicted by the Lambda CDM cosmology. We also conjecture that cosmic downsizing corresponds to a shift towards star formation in both lower mass objects and void regions closer to the present epoch. We present evidence that void dwarf galaxies may have a higher ratio of dark matter halo mass to stellar mass when compared to dwarf galaxies in denser environments.
Download or read book The Role of the Group Environment in Galaxy Evolution written by Sean Liam McGee and published by . This book was released on 2010 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of typically sized galaxies in the local Universe reside in a common dark matter halo with other similar galaxies known as a galaxy group. However, this was not always the case. Nine billion years ago, when the universe was one third its current age, these galaxies were almost exclusively the only massive galaxy in their dark matter haloes. In this thesis, I use both observational and theoretical methods to attempt to understand the effect these galaxy groups have on the evolution of galaxy properties.
Download or read book Obscured Activity and the Role of Environment on Galaxy Evolution at High Redshift written by and published by . This book was released on 2007 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Roles of Environment in Galaxy Evolution written by Ann Zabludoff and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
