Download or read book Tracing Galaxies Through Cosmic Time written by Joel Robert Leja and published by . This book was released on 2019 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, I describe how observations of stellar mass and star formation rate properties of galaxies over cosmic time can be converted into the stellar mass assembly history of galaxies. I first postulate that the stellar mass rank-order of galaxies is preserved through cosmic time, and test whether this is true in a semi-analytical model of galaxy formation. I find that assuming preservation of stellar mass rank order reproduces the median stellar mass growth of a galaxy population to within 40% from z = 3 to z = 0 over a wide range in galaxy properties. I establish that the discrepancy mainly results from scatter in stellar mass growth rates, and galaxy-galaxy mergers. The main uncertainties in this work are that the semi-analytical model does not reproduce the observed evolution of the stellar mass function, and that the scatter in growth rates about the median may be substantial.
Download or read book Tracing Back the Cosmic History of Galaxy Formation with the Large ALMA Interferometer written by Maximilien Franco and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of this thesis was to better understand the cosmic history of galaxy formation thanks to the largest cosmological survey with the large ALMA interferometer. This observation was preformed in a region of the sky, the GOODS-South field, which benefits from the deepest observations of the Hubble Space Telescope, the Spitzer and Herschel infrared space observatories, as well as data from the Chandra X-ray telescope and the VLA Radio Interferometer. These observations at 1.1mm with ALMA therefore complete this multi-wavelength panorama, and make this region of the sky a leading laboratory for the study of the evolution of galaxies. The observation with ALMA allows us to observe this region of the sky without being affected by the confusion limit that affected Herschel, and to search for more distant galaxies. For the first time, we can study dust-obscured star formation at z > 2 over a large enough area to reduce different observational biases.A large part of this thesis was devoted to the scientific exploitation of this 1.1mm cosmological image. This was done by analysing the image from the interferometric data, precisely characterising the survey, defining detectability thresholds and indicators that can quantify the credibility of detections, and carrying out simulations on these images. We then extracted and identified the galaxies present in the image.This analysis shows that ALMA surveys can reveal new galaxies that are not detected by the deepest surveys conducted with the Hubble Space Telescope. These ``dark" galaxies are among the most massive and distant galaxies in this region of the sky. The discovery of these new dark galaxies, which represent of the order of 10 - 20% of the ALMA detections, suggests that the number of massive star-forming galaxies in the distant universe may be much larger than previously expected. This work has also made it possible to determine properties of the galaxies detected by ALMA, through the modelling of their spectral energy distributions: the star formation rate, the masses of gas and dust, the dust temperature, the time required for a galaxy to consume its gas, the relationship between the infrared luminosity and the radio luminosity, and the excess of the infrared component in the spectrum of a galaxy. Analysis of these findings suggests that massive galaxies at high redshift consume their gas slowly to form stars and indicate that these galaxies are the ideal progenitors of passive galaxies at z∼2.
Download or read book The Assembly of Galaxies Over Cosmic Time written by Yicheng Guo and published by . This book was released on 2012 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: To understand how galaxies were assembled across the cosmic time remains one of the most outstanding questions in astronomy. The core of this question is how today's Hubble Sequence, namely the differentiation of galaxy morphology and its correlation to galaxy physical properties, is formed. In this thesis, we investigate the origin of the Hubble Sequence through galaxies at z~2, an epoch when the cosmic star formation activity reaches its peak and the properties of galaxies undergo dramatic transitions. Galaxies at z~2 have two important features that are distinct from nearby galaxies: much higher frequency of clumpy morphology in star-forming systems, and much compacter size. To understand the nature of the two features requires investigations on the sub-structure of galaxies in a multi-wavelength way. In this thesis, we study samples of galaxies that are selected from GOODS and HUDF, where ultra-deep and high-resolution optical and near-infrared images allow us to study the stellar populations of the sub-structures of galaxies at the rest-frame optical bands for the first time, to answer two questions: (1) the nature of kiloparsec-scale clumps in star-forming galaxies at z$\sim$2 and (2) the existence of color gradient and stellar population gradient in passively evolving galaxies at z~2, which may provide clues to the mechanisms of dramatic size evolution of this type of galaxies. We further design a set of color selection criteria to search for dusty star-forming galaxies and passively evolving galaxies at z~3 to explore the question: when today's Hubble Sequence has begun to appear.
Download or read book Reimagining Science Education in the Anthropocene written by Maria F. G. Wallace and published by Springer Nature. This book was released on 2021-12-07 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access edited volume invites transdisciplinary scholars to re-vision science education in the era of the Anthropocene. The collection assembles the works of educators from many walks of life and areas of practice together to help reorient science education toward the problems and peculiarities associated with the geologic times many call the Anthropocene. It has become evident that science education—the way it is currently institutionalized in various forms of school science, government policy, classroom practice, educational research, and public/private research laboratories—is ill-equipped and ill-conceived to deal with the expansive and urgent contexts of the Anthropocene. Paying homage to myopic knowledge systems, rigid state education directives, and academic-professional communities intent on reproducing the same practices, knowledges, and relationships that have endangered our shared world and shared presents/presence is misdirected. This volume brings together diverse scholars to reimagine the field in times of precarity.
Download or read book Cosmic Countdown written by Phillips and published by Tredition Gmbh. This book was released on 2024-06-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title offers several advantages: - Intrigue: "The Big Bang's Echo" sparks curiosity about the evidence for the universe's origin. - Clarity: "Universe's History" defines the focus. - Unveiling: "Unveiling" emphasizes the ongoing process of discovery. Here's a breakdown of the content it could cover: - From the Beginning: Briefly introduce the Big Bang theory as the prevailing explanation for the universe's origin. - Echoes of Creation: Discuss how scientists use various forms of evidence to trace the history of the universe, such as: o Cosmic Microwave Background Radiation (CMB) o Abundance of light elements like hydrogen and helium o Large-scale structure formation (galaxies and clusters) - A Cosmic Timeline: o Highlight how this evidence helps us piece together a timeline of major events in the universe's history, from the hot Big Bang to the formation of galaxies and stars. - A Journey Through Time: o Briefly mention the limitations of current knowledge and ongoing research to further refine our understanding of the universe's early stages.
Download or read book Tracing Cosmic Evolution with Galaxy Clusters written by Stefano Borgani and published by . This book was released on 2002 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galaxies Through Cosmic Time written by Amber Bauermeister and published by . This book was released on 2012 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decade, molecular gas observations have begun probing the high redshift universe in a systematic way using increasingly powerful millimeter instruments. This work has significantly advanced our understanding of the history of gas consumption by star formation in galaxies, revealing the high redshift universe to be similar in many ways to what we know locally. Specifically, molecular gas studies suggest that at both high and low redshift, the molecular gas reservoir in galaxies is insufficient to support on-going star formation. This is the molecular gas depletion problem, and motivates the research presented in this dissertation. I first investigate the molecular gas depletion problem on cosmic scales. Using the observed cosmic densities of the star formation rate, atomic gas and molecular gas, combined with measurements of the molecular gas depletion time in local galaxies, I derive the history of gas consumption by star formation from z = 0 to z ~ 4. I show that models in which the molecular gas is not replenished, or is only replenished by atomic gas, are not consistent with observational constraints. I find that star formation on cosmic timescales must be fueled by intergalactic ionized gas at an average rate that roughly traces the star formation rate density of the universe. Further, I predict the volume averaged density of molecular gas to increase by a factor of 1.5 - 10 to z ~ 1.5 over the currently measured value, which implies that galaxies at high redshift must, on average, be more molecular gas-rich than they are at the present epoch, consistent with observations. Next I focus on the observational constraints on the molecular gas content of galaxies from z ~ 1 - 2 to today. Recent observations suggest z ~ 1 - 2 galaxies harbor molecular gas reservoirs an order of magnitude larger than their local counterparts, implying significant evolution of the molecular gas content of galaxies over the past 8 billion years. However, this period of time has been relatively un-observed in molecular gas. To fill in this observational gap, I carry out the Evolution of molecular Gas in Normal Galaxies (EGNoG) survey, a study of molecular gas in 31 star-forming galaxies from z = 0.05 to z = 0.5. With observations of the CO(1-0) and CO(3-2) rotational lines using the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the EGNoG survey accomplishes two goals: tracing the evolution of the molecular gas content of galaxies at intermediate redshifts and constraining the excitation of the molecular gas in these galaxies. With 24 detections out of 31 observed galaxies, I calculate an average molecular gas fraction of 7 - 20% at z ~ 0.05 - 0.5, which is in line with observations at high and low redshift and agrees well with the evolution predicted by a simple empirical prescription for gas consumption by star formation in galaxies from z ~ 1 - 2 to today. The EGNoG observations of four galaxies at z = 0.3 (the gas excitation subsample) yield robust detections of both lines in three galaxies (and an upper limit on the fourth). I find an average line ratio, r31 = L'(CO(3-2)) / L'(CO(1-0)), of 0.46 ± 0.07 (with systematic errors less than 40%), which implies sub-thermal excitation of the CO(3-2) line. As the EGNoG galaxies are representative of the main sequence of star-forming galaxies, I extend this result to include main sequence galaxies at high redshift. To support the observations carried out at CARMA as part of the EGNoG survey, I give two appendices. The first details the data reduction and flux measurement for the EGNoG survey, including a description of the use of polarized calibrators to calibrate data from single, linearly polarized feeds. In the second appendix, I describe the absolute flux calibration of CARMA data and the automated monitoring system I helped put in place in order to maintain a historical record of the flux of common calibrators. Finally, I return to the gas depletion problem in the local universe. I carry out a pilot study of atomic (HI) gas in groups of galaxies in order to investigate the role of tidal interactions in transporting atomic gas from the outskirts of galaxy disks to the central regions so that it may replenish the molecular gas and fuel ongoing star formation. I image three groups of galaxies in the 21 cm line of HI with the Allen Telescope Array (ATA), detecting many galaxies not previously observed in HI as well as four previously undetected clouds of HI between galaxies that account for up to 3% of the HI reservoir of the groups. To investigate the potential role of this gas in the ongoing star formation in the group, I compare the mass of the detected HI gas in and between galaxies in the group to the estimated star formation rates of the group members.
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 How Did the First Stars and Galaxies Form written by Abraham Loeb and published by Princeton University Press. This book was released on 2010-07-19 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: A concise introduction to cosmology and how light first emerged in the universe Though astrophysicists have developed a theoretical framework for understanding how the first stars and galaxies formed, only now are we able to begin testing those theories with actual observations of the very distant, early universe. We are entering a new and exciting era of discovery that will advance the frontiers of knowledge, and this book couldn't be more timely. It covers all the basic concepts in cosmology, drawing on insights from an astronomer who has pioneered much of this research over the past two decades. Abraham Loeb starts from first principles, tracing the theoretical foundations of cosmology and carefully explaining the physics behind them. Topics include the gravitational growth of perturbations in an expanding universe, the abundance and properties of dark matter halos and galaxies, reionization, the observational methods used to detect the earliest galaxies and probe the diffuse gas between them—and much more. Cosmology seeks to solve the fundamental mystery of our cosmic origins. This book offers a succinct and accessible primer at a time when breathtaking technological advances promise a wealth of new observational data on the first stars and galaxies. Provides a concise introduction to cosmology Covers all the basic concepts Gives an overview of the gravitational growth of perturbations in an expanding universe Explains the process of reionization Describes the observational methods used to detect the earliest galaxies
Download or read book The Assembly of Massive Galaxies Through Cosmic Time written by Immacolata Donnarumma and published by . This book was released on 2004 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galaxies and the Universe written by Allan Sandage and published by . This book was released on 1975 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Star Formation and the Evolution of Massive Galaxies Across Cosmic Time written by Jamie Richard Ownsworth and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Probing Galaxies Through Quasar Absorption Lines IAU C199 written by International Astronomical Union. Colloquium and published by Cambridge University Press. This book was released on 2005-12 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Review of recent research in the field of quasar absorption line systems.
Download or read book Galaxy evolution through clusters and cosmic time written by Kyle P. Lane and published by . This book was released on 2007 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Origin And Evolution Of The Universe From Big Bang To Exobiology Second Edition written by Matthew A Malkan and published by World Scientific. This book was released on 2020-08-12 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'This book presents a clear, highly readable view of science's best understanding of how things in the Universe came to be the way they are. Each chapter is written by a leading expert in that sub-field. Together they cover nearly all major advances made in the past century, in fields from cosmology to exobiology.'Joseph H Taylor Jr.Nobel Laureate in Physics, 1993'An exhilarating tour of the Universe from true experts. For those who thirst to know how we know what we know about our place in the Universe, reading this book will be a richly rewarding experience.'Adam G RiessNobel Laureate in Physics, 2011'These are fascinating essays about the nature of the world around us by people who write well and understand what they are writing about.'P James E PeeblesNobel Laureate in Physics, 2019The book provides a broad overview of what we currently know about the Origin and Evolution of the Universe. The goal is to be scientifically comprehensive but concise. We trace the origins from the Big Bang and cosmic expansion, to the formation of galaxies, heavy elements, stars and planets as abodes for life. This field has made stunning progress since the first edition of this book. At that time, there were no known planets outside of our own Solar System (compared with the many thousands currently being studied). The origin of massive black holes was pure speculation (compared with the very recent detection of the first gravitational waves from space, produced by the cataclysmic merger of two surprisingly large black holes). And the most important energy in the Universe, now known as the Dark Energy which is accelerating the expansion, had not been discovered. We aim to bring lay readers with an interest in science 'up to speed' on all of these key discoveries that are part of the panorama of cosmic evolution, which has ultimately lead to our existence on Earth.Related Link(s)
Download or read book Introduction to Galaxy Formation and Evolution written by Andrea Cimatti and published by Cambridge University Press. This book was released on 2019-10-17 with total page 587 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive examination of nearly fourteen billion years of galaxy formation and evolution, from primordial gas to present-day galaxies.
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.
