Download or read book Interpreting New Galaxy Large scale Structure Measurements and the Galaxy Halo Connection written by Angela Marie Berti and published by . This book was released on 2020 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: The galaxy distribution in the joint space of stellar mass and star formation rate (SFR) is observed to be bimodal, with distinct star-forming (high SFR) and quiescent (low SFR) populations across many orders of magnitude in stellar mass. The absence of a significant population of intermediate-stage galaxies implies that galaxies tend to cease star formation and become quiescent relatively rapidly, and the physical origins of this rapid quenching are an open question in the field of galaxy evolution. Recent progress in cosmological simulations of dark matter structure evolution, as well as in statistical modeling of how galaxies inhabit dark matter halos, suggest a nuanced coevolutionary relationship between galaxies and the dark matter halos galaxies reside in (the "galaxy-halo connection"), in which the statistical galaxy content of a halo depends on more than halo mass. One class of these galaxy-halo connection models are those that incorporate galaxy assembly bias, a general term for the dependence of galaxy properties on halo properties other than mass. For example, distinct stellar-to-halo mass relations for star-forming and quiescent central galaxies is a form of galaxy assembly bias that could manifest as an anticorrelation of galaxy SFR with clustering amplitude, if the trend is independent of stellar (or halo) mass. In this dissertation we present the first measurements of galactic conformity, or the tendency of neighboring galaxies to share the star formation properties of an adjacent central galaxy, on two-halo scales beyond the local universe (to z~1). We then measure the clustering of isolated galaxies as a proxy for central galaxies, separately for star-forming and quiescent galaxies, to test predictions of galaxy-halo models reflecting galaxy assembly bias. Finally, we measure the joint dependence of clustering on stellar mass and SFR. With mock galaxy catalogs derived from simulations and an empirical galaxy evolution model we quantify and compensate for the effects of systematic biases on these measurements. A parallel theme of this dissertation is demonstrating how existing galaxy surveys beyond the local universe are at the cusp of probing the volumes needed for statistically significant tests of theoretical predictions of various models of galaxy evolution.
Download or read book Learning and Interpreting the Galaxy halo Connection in Cosmic Simulations written by Harry George Chittenden and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galaxy Proto clusters as an Interface Between Structure Cluster and Galaxy Formation written by Yi-Kuan Chiang and published by . This book was released on 2016 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proto-clusters, the distant progenitor large-scale structures of present day galaxy clusters, represent a key phase of cluster growth during which most of the galaxies were still rapidly forming stars. They are potentially powerful cosmological probes, and are unique laboratories to study dark matter assembly, the cosmic baryon cycle, and the environmental impact on galaxy evolution. Albeit its pivotal role in understanding cluster formation, only a small and heterogeneous sample of proto-clusters has been observed to date. Theoretical characterizations have also remained relatively unexplored. In this dissertation, I present baseline models, detailed theory predictions, and broad observational applications of proto-clusters using state-of-the-art numerical simulations and deep-wide galaxy surveys. A dual focus of both structure formation and galaxy evolution is given throughout the thesis. To prepare for large statistical studies in upcoming surveys like the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), the Subaru Prime Focus Spectrograph (PFS) survey, and the Wide Field Infrared Survey Telescope (WFIRST) survey, I develop key machinery to connect the main observables of proto-clusters with dark matter structure formation using simulations as a guide. In Chapter 2 and 3, I present, for the first time, a thorough analysis of the main properties of proto-clusters using ~3000 clusters in a set of cosmological N-body simulations and semi-analytic galaxy models. I characterize the growth of proto-clusters and their core halos in size and mass with cosmic time. I show that the progenitor regions of galaxy clusters can already be identified in galaxy surveys at very early times (at least up to z~5), provided that the galaxy overdensities are measured on a sufficiently large scale (5--30 Mpc comoving) and with sufficient statistics. I present the overdensities in matter, dark matter halos, and galaxies as functions of present-day cluster mass, redshift, bias, and selection window size that can be used to interpret the wide range of structures found in real surveys. A table of proto-cluster candidates selected from the literature is provided, and I discuss their properties in light of our simulation predictions. In Chapter 4 I report the discovery of a large sample of proto-cluster candidates in the 1.62 deg^2 COSMOS/UltraVISTA field traced by optical/infrared selected galaxies with photometric redshifts. By comparing properly smoothed three-dimensional galaxy density maps of the observations and a set of matched simulations incorporating the main observational effects, I found 36 candidate structures at 1.610^14} M_sun. With solely photometric redshifts, I successfully rediscover two spectroscopically confirmed structures in this field, suggesting that our algorithm is robust. This work is the first large sample of uniformly selected proto-cluster candidates, providing rich targets for spectroscopic follow-up and subsequent studies of cluster formation. Because of the need of precise galaxy redshifts for density mapping and the prevalence of star formation before quenching, nearly all the proto-clusters known to date were confirmed by spectroscopy of galaxies with strong emission lines. In Chapter 5 I develop a semi-empirical model for Lya escape and generate a set of mock Lya emitter catalogs. This formalism provides a realistic modeling of the galaxy bias, the scatter of the bias, and the stochasticity of the galaxy-dark matter halo connection, which has an enormous potential for studies of the large-scale structure at high redshift. The model suggests that there are two distinct regimes to power a Lya emitter. For massive galaxies, Lya emitters are preferentially less dusty and slightly less metal enriched, while their ages and star formation rates are indistinguishable from other star-forming galaxies of the same mass. In contrast, low mass Lya emitters M_star
Download or read book Applications of the Halo Model to Large Scale Structure Measurements of the Luminous Red Galaxies written by Beth Ann Reid and published by . This book was released on 2008 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: The power spectrum of density fluctuations in the evolved universe provides constraints on cosmological parameters that are complementary to cosmic microwave background and other astronomical probes. The Sloan Digital Sky Survey (SDSS) Luminous Red Galaxy (LRG) sample probes a volume of ∼ 3 (Gpc) 3, and systematic errors in modeling the nonlinearities limit our ability to extract information on the shape of the linear power spectrum. There are three main effects that distort the observed power spectrum from the linear power spectrum: nonlinear gravitational evolution, redshift space distortions, and a nonlinear relation between the galaxy density field and the underlying matter density field. In this thesis we introduce a new method to mitigate the latter two distortions and rely on carefully tuned N-body simulations to model the first.
Download or read book The Minnesota Lectures on Clusters of Galaxies and Large scale Structure written by John M. Dickey and published by . This book was released on 1988 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Outskirts of Galaxies written by Johan H. Knapen and published by Springer. This book was released on 2017-07-09 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book consists of invited reviews written by world-renowned experts on the subject of the outskirts of galaxies, an upcoming field which has been understudied so far. These regions are faint and hard to observe, yet hide a tremendous amount of information on the origin and early evolution of galaxies. They thus allow astronomers to address some of the most topical problems, such as gaseous and satellite accretion, radial migration, and merging. The book is published in conjunction with the celebration of the end of the four-year DAGAL project, an EU-funded initial training network, and with a major international conference on the topic held in March 2016 in Toledo. It thus reflects not only the views of the experts, but also the scientific discussions and progress achieved during the project and the meeting. The reviews in the book describe the most modern observations of the outer regions of our own Galaxy, and of galaxies in the local and high-redshift Universe. They tackle disks, haloes, streams, and accretion as observed through deep imaging and spectroscopy, and guide the reader through the various formation and evolution scenarios for galaxies. The reviews focus on the major open questions in the field, and explore how they can be tackled in the future. This book provides a unique entry point into the field for graduate students and non-specialists, and serves as a reference work for researchers in this exciting new field.
Download or read book Cosmology and Galaxy Formation written by Rachel Marie Reddick and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary goal of this dissertation is to examine the relationship between galaxies and their dark matter halos. Understanding this relationship is instrumental to using modern galaxy surveys as probes of cosmology and to teasing out the details of galaxy formation. I will focus on methods relating to dark matter only simulations and large area surveys, and the use of galaxy clusters. I begin with an exploration of subhalo abundance matching, a commonly used empirical method for relating galaxies to dark matter halos in dark matter only simulations. The most obvious approach is to simply place the most massive, or most luminous, galaxy into the most massive dark matter halo. Nonetheless, there are several possible variations that I explore within the general class of subhalo abundance matching models. Results from these models are then validated against measurements drawn from the Sloan Digital Sky Survey. These models are used to test a method for obtaining cosmology while marginalizing over the details of the galaxy-halo relationship. This method combines two-point clustering measurements with a measurement of cluster mass and richness to provide constraints on the density of dark matter in the universe. The additional cluster statistics are essential to breaking degeneracies between the galaxy-halo relationship and the cosmology that occur when fitting to the two-point clustering alone. While this method had previously been used in the literature, this dissertation adds by performing a fully consistent analysis of multiple galaxy models, demonstrating that so long as the galaxy-halo connection can be adequately modeled by a halo occupation distribution that the cosmology can be estimated in an unbiased manner. Returning to observations, I examine the clusters obtained using the redMaPPer cluster finder applied to SDSS. The trends found are generally consistent with previous cluster catalogs, but take advantage of the reduced scatter in the mass-richness relationship. The results have significant implications for the formation of clusters, particularly the importance of recent mergers on the galaxy statistics and for redshift evolution. This analysis is also applied to early data from DES, showing the evolution of red cluster galaxies up to z=0.9. Finally, I discuss the potential for future work. This includes application of redMaPPer and the M/N formalism to DES and future surveys, as well as directions for using galaxy cluster catalogs as a tool for understanding the formation of the most massive galaxies and their dark matter halos.
Download or read book Precision Cosmology with Galaxy Cluster Surveys written by Hao-Yi Wu and published by Stanford University. This book was released on 2011 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: The acceleration of the universe, which is often attributed to "dark energy, " has posed one of the main challenges to fundamental physics. Galaxy clusters provide one of the most sensitive probes of dark energy because their abundance reflects the growth rate of large-scale structure and the expansion rate of the universe. Several large galaxy cluster surveys will soon provide tremendous statistical power to constrain the properties of dark energy; however, the constraining power of these surveys will be determined by how well systematic errors are controlled. Of these systematic errors, the dominant one comes from inferring cluster masses using observable signals of clusters, the so-called "observable--mass distribution." This thesis focuses on extracting dark energy information from forthcoming large galaxy cluster surveys, including how we maximize the cosmological information, how we control important systematics, and how precisely we need to calibrate theoretical models. We study how multi-wavelength follow-up observations can improve cluster mass calibration in optical surveys. We also investigate the impact of theoretical uncertainties in calibrating the spatial distributions of galaxy clusters on dark energy constraints. In addition, we explore how the formation history of galaxy clusters impacts the self-calibration of cluster mass. In addition, we use N-body simulations to develop a new statistical sample of cluster-size halos in order to further understand the observable--mass distribution. We study the completeness of subhalos in our cluster sample by comparing them with the satellite galaxies in the Sloan Digital Sky Survey. We also study how subhalo selections impact the inferred correlation between formation time and optical mass tracers, including cluster richness and velocity dispersion.
Download or read book Formation and Evolution of Galaxies and Large Scale Structure in the Universe written by Scot Stewart Olivier and published by . This book was released on 1991 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulations of Galaxy Formation and Large Scale Structure written by Felix Stoehr and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2009-12 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work we use the N-body resimulation technique to address aspects of structure formation. In the first chapter we study the influence of the local environment of DM haloes on their properties. In the second chapter we address the so-called "substructure problem" which is one of the major challenges of the CDM model of cosmology. We perform ultra-high resolution simulations of the assembly of a Milky Way type dark matter halo within its full cosmological context and propose a new analytical fitting formula (SWTS) which provides a better fit to the simulated Milky Way halo than the NFW or Moore profiles do. In the third chapter we use our ultra-high resolution simulations to study the possible -ray signal from dark matter annihilation. If such a signal was detected, the nature of the dark matter, the answer to one of the most important questions of modern cosmology, would be known. (urn: nbn: de: bvb:19-16446)"
Download or read book Comparison of the Large Scale Structure of the Galactic System with that of Other Stellar Systems written by N. G. Roman and published by Cambridge University Press. This book was released on 2015-05-21 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: First published in 1958, this book examines the Galactic System in the light of then-recent developments in radio astronomy.
Download or read book Modeling Large Scale Structure from Photometric Surveys written by and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cosmological Physics written by J. A. Peacock and published by Cambridge University Press. This book was released on 1999 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive and authoritative introduction to contemporary cosmology for advanced undergraduate and graduate students.
Download or read book Fundamentals of Galaxy Dynamics Formation and Evolution written by Ignacio Ferreras and published by UCL Press. This book was released on 2019-04-02 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies, along with their underlying dark matter halos, constitute the building blocks of structure in the Universe. Of all fundamental forces, gravity is the dominant one that drives the evolution of structures from small density seeds at early times to the galaxies we see today. The interactions among myriads of stars, or dark matter particles, in a gravitating structure produce a system with fascinating connotations to thermodynamics, with some analogies and some fundamental differences. Ignacio Ferreras presents a concise introduction to extragalactic astrophysics, with emphasis on stellar dynamics, and the growth of density fluctuations in an expanding Universe. Additional chapters are devoted to smaller systems (stellar clusters) and larger ones (galaxy clusters). Fundamentals of Galaxy Dynamics, Formation and Evolution is written for advanced undergraduates and beginning postgraduate students, providing a useful tool to get up to speed in a starting research career. Some of the derivations for the most important results are presented in detail to enable students appreciate the beauty of maths as a tool to understand the workings of galaxies. Each chapter includes a set of problems to help the student advance with the material.
Download or read book The Discovery of Cosmic Voids written by Laird A. Thompson and published by Cambridge University Press. This book was released on 2020-12-10 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The large-scale structure of the Universe is dominated by vast voids with galaxies clustered in knots, sheets, and filaments, forming a great 'cosmic web'. In this personal account of the major astronomical developments leading to this discovery, we learn from Laird A. Thompson, a key protagonist, how the first 3D maps of galaxies were created. Using non-mathematical language, he introduces the standard model of cosmology before explaining how and why ideas about cosmic voids evolved, referencing the original maps, reproduced here. His account tells of the competing teams of observers, racing to publish their results, the theorists trying to build or update their models to explain them, and the subsequent large-scale survey efforts that continue to the present day. This is a well-documented account of the birth of a major pillar of modern cosmology, and a useful case study of the trials surrounding how this scientific discovery became accepted.
Download or read book Shapes Of Galaxies And Their Dark Halos The Proceedings Of The Yale Cosmology Workshop written by Priyamvada Natarajan and published by World Scientific. This book was released on 2002-03-28 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the proceedings of a very topical workshop aimed at understanding the shapes of the baryonic and dark matter components of galaxies. Several groups presented their recent results from observations and numerical N-body simulations.
Download or read book Cell Count Moments in the Halo Model written by Anand Balaraman and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: One of the main goals of the study of Large Scale Structures is to understand the clustering properties of the galaxy distribution from fundamental principles. Purely baryonic theories of Structure Formation failed to produce the desired results, suggesting strongle that the Universe is filled with some kind of dark matter which is non baryonic in nature and interacts weakly with ordinary baryonic matter. At this point of time it is not possible to determine the distribution of dark matter observationally. However we can observe the distribution of galaxies. Observations show that galaxy clustering on small scales is non linear and an analytical understanding of Non Linear Gravitational Clustering (NLGC) is difficult to achieve. The higher order correlation functions cannot be determined analytically and the information available in full correlation functions derived from galaxy catalogs, if not beyond the reach of our computational abilities, is beyond our ability to handle. Count in cells offer a manageable alternative statistical measure and the Halo model a useful phenomenological model for studying NLGC. We study the moments of Count in cells in the Halo model. Halo model is used to predict, calibrate and interpret redshift distortions and finite volume effects in the measurements of galaxy correlation functions, weak gravitational lensing, Lyman-alpha forest and CMB Sunyaev-Zel'dovich foregrounds. In order to be confident of these results it is important to test the model in as many ways as is possible.
