Download or read book Multiphase Galactic Outflows written by Andrin Flûtsch 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 Physical Conditions and Scaling Relations of Multi phase Galactic Outflows written by and published by . This book was released on 2016 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: Star formation injects energy and momentum into the interstellar medium, accelerating the gas outward in a galaxy-scale outflow. These outflows eject large amounts of gas out of star-forming regions, helping to control the number of stars formed in a galaxy. In this thesis, I present new observational studies of galactic outflows in the local universe that describe the physical conditions of outflows and how the physical conditions scale with host galaxy properties. I find shallow, yet statistically significant, scaling relations between the outflow velocity and both the star formation rate and the stellar mass of their host galaxies. These scaling relations describe the acceleration of gas out of galaxies, and provide constraints for galaxy evolution models. In particular, I find that low-mass galaxies (stellar mass less than 10^10.5) generate low-ionization outflows faster than their escape velocities, while high-mass galaxies generally do not, unless they are merging with another galaxy. I then explore a variety of ionic transitions that probe the different ionization stages of the outflow. The outflow velocity of each transition depends on the strength of the transition, and I model the outflows as a single co-moving phase. Photo-ionization models determine the ionization structure and metallicities of the outflows. For the local merger NGC 6090, I combine these ionization models with detailed fits to the optical depth and covering fraction of the Si IV absorption lines. These fits determine how the velocity, density, covering fraction and mass outflow rate scales with distance from the starburst. Finally, I study the molecular outflow of M 82 using three different CO emission lines. I model the temperature and density of the molecular gas to estimate the total molecular mass outflow rate, without relying on uncertain conversion factors. I compare the mass outflow rate to the star formation rate and an estimate of the inflow rate to characterize the molecular baryon cycle of M 82. Taken as a whole, this thesis explores the physical properties of nearby galactic outflows, studying how these physical properties scale with host galaxy properties. These results describe the efficiency of star formation, and the cycling of gas out galaxies.
Download or read book High Velocity Clouds written by Hugo van Woerden and published by Springer. This book was released on 2010-10-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: On the occasion of the retirement of Ulrich Schwarz, a symposium was held in Groningen in May of 1996, celebrating his contributions to the study of the int- stellar medium, including his work on the high-velocity clouds. The coming together of many specialists in the latter ?eld prompted the idea of compiling a book c- taining their contributions, and summarizing the status of our understanding of the high-velocity cloud phenomenon. This seemed especially worthwhile at the time, since many exciting developments were taking place. After the discovery of some H i clouds with high velocities, about 40 years ago, the subject had been dominated by 21-cm observations of H i emission. Starting in the mid-1980s much progress was being made because of the availability of new instruments, such as large ground-based optical telescopes and UV observatories in space. The connections between the work on high-velocity clouds and other studies of the properties of the (hot) interstellar medium also became clearer.
Download or read book Simulating the Multi phase Interstellar Medium and Galactic Outflows written by Tim-Eric Rathjen and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulating Multiphase Galactic Halos written by Iryna Sotolongo Butsky and published by . This book was released on 2021 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: All galaxies evolve embedded in a vast gaseous halo --- the circumgalactic medium (CGM) --- that dwarfs the mass and spatial extent of the stars in the galactic disk. Recent ultraviolet (UV) absorption studies reveal that the CGM has a rich, multiphase structure shaped by metal-rich galactic winds that expel the byproducts of stellar evolution and pristine inflows from the intergalactic medium. Galaxy evolution is intricately tied to the state of its CGM, as galaxies depend on a consistent supply of cool gas in order to form new stars. While current state-of-the-art simulations excel at reproducing galactic disk properties, most struggle to simultaneously reproduce the observed abundance, properties, and kinematic structure of multiphase CGM gas.In this thesis, I argue that the missing piece is likely a nonthermal component in the form of cosmic rays. I implement cosmic-ray physics into the {\sc enzo} and {\sc ChaNGa} simulation codes and use a combination of idealized, isolated-galaxy, and cosmological-zoom-in simulations to demonstrate the role of cosmic rays in driving galactic outflows and shaping the multiphase CGM. Throughout this work, I demonstrate how uncertainties in existing cosmic-ray transport models can lead to qualitatively different CGM structures, and motivate the need for more robust models of cosmic-ray hydrodynamics. Additionally, I explore more direct techniques for comparing simulations against observations. Using synthetic spectroscopy, I demonstrate how cosmic rays can naturally explain the observed kinematic alignment of multiphase CGM gas. I then use synthetic observations to demonstrate the prevalence and observational signatures of cool and warm gas in the halos around the most massive galaxies, which are traditionally studied with X-ray emission from their hot, dense inner regions.
Download or read book Supernovae Feedback in Galaxy Formation written by Miao Li and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Feedback -- from stars and supermassive black holes -- is the bottleneck of our understanding on galaxy formation: it is likely to be critical, but neither the working mechanism nor the impact is clear. Supernovae (SNe), the dominant feedback force associated with stars, is the subject of this thesis. We use high-resolution, 3D hydrodynamic simulations to study: (i) how a SN blast wave imparts energy to a multiphase ISM; (ii) how multiple SNe regulate a multiphase ISM; (iii) how SNe drive galactic outflows. We focus on better understanding the physics, quantifying the impacts, and testing the simulations against observations.
Download or read book Similarity and Dimensional Methods in Mechanics written by L. I. Sedov and published by CRC Press. This book was released on 2018-05-04 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Similiarity and Dimensional Methods in Mechanics, 10th Edition is an English language translation of this classic volume examining the general theory of dimensions of physical quantities, the theory of mechanical and physical similarity, and the theory of modeling. Several examples illustrate the use of the theories of similarity and dimensions for establishing fundamental mechanical regularities in aviation, explosions, and astrophysics, as well as in the hydrodynamics of ships. Other interesting areas covered include the general theory of automodel motions of continuum media, the theory of propagation of explosion waves in gases, the theory of one-dimensional nonestablished motion in gases, the fundamentals of the gas-dynamics theory of atom-bomb explosion in the atmosphere and the theory of averaging of gaseous flows in channels. Aspects of modeling include the dimensionless characteristics of compressor operation, the theories of engine thrust, and efficiency of an ideal propeller for subsonic and supersonic speeds. Similiarity and Dimensional Methods in Mechanics, 10th Edition is an ideal volume for researchers and students involved in physics and mechanics.
Download or read book Physics of the Interstellar and Intergalactic Medium written by Bruce T. Draine and published by Princeton University Press. This book was released on 2010-12-20 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a comprehensive and richly illustrated textbook on the astrophysics of the interstellar and intergalactic medium--the gas and dust, as well as the electromagnetic radiation, cosmic rays, and magnetic and gravitational fields, present between the stars in a galaxy and also between galaxies themselves. Topics include radiative processes across the electromagnetic spectrum; radiative transfer; ionization; heating and cooling; astrochemistry; interstellar dust; fluid dynamics, including ionization fronts and shock waves; cosmic rays; distribution and evolution of the interstellar medium; and star formation. While it is assumed that the reader has a background in undergraduate-level physics, including some prior exposure to atomic and molecular physics, statistical mechanics, and electromagnetism, the first six chapters of the book include a review of the basic physics that is used in later chapters. This graduate-level textbook includes references for further reading, and serves as an invaluable resource for working astrophysicists. Essential textbook on the physics of the interstellar and intergalactic medium Based on a course taught by the author for more than twenty years at Princeton University Covers radiative processes, fluid dynamics, cosmic rays, astrochemistry, interstellar dust, and more Discusses the physical state and distribution of the ionized, atomic, and molecular phases of the interstellar medium Reviews diagnostics using emission and absorption lines Features color illustrations and detailed reference materials in appendices Instructor's manual with problems and solutions (available only to teachers)
Download or read book Riemann Solvers and Numerical Methods for Fluid Dynamics written by Eleuterio F. Toro and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 635 pages. Available in PDF, EPUB and Kindle. Book excerpt: High resolution upwind and centered methods are today a mature generation of computational techniques applicable to a wide range of engineering and scientific disciplines, Computational Fluid Dynamics (CFD) being the most prominent up to now. This textbook gives a comprehensive, coherent and practical presentation of this class of techniques. The book is designed to provide readers with an understanding of the basic concepts, some of the underlying theory, the ability to critically use the current research papers on the subject, and, above all, with the required information for the practical implementation of the methods. Applications include: compressible, steady, unsteady, reactive, viscous, non-viscous and free surface flows.
Download or read book Galaxy Mergers with Adaptive Mesh Refinement written by and published by . This book was released on 2011 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: In hierarchical structure formation, merging of galaxies is frequent and known to dramatically affect their properties. To comprehend these interactions high-resolution simulations are indispensable because of the nonlinear coupling between pc and Mpc scales. To this end, we present the first adaptive mesh refinement (AMR) simulation of two merging, low mass, initially gas-rich galaxies (1.8 x 101° M{sub {circle_dot}} each), including star formation and feedback. With galaxies resolved by ≈ 2 x 107 total computational elements, we achieve unprecedented resolution of the multiphase interstellar medium, finding a widespread starburst in the merging galaxies via shock-induced star formation. The high dynamic range of AMR also allows us to follow the interplay between the galaxies and their embedding medium depicting how galactic outflows and a hot metal-rich halo form. These results demonstrate that AMR provides a powerful tool in understanding interacting galaxies.
Download or read book Properties and Impact of Active Galactic Nuclei driven Outflows Through Cosmic Time written by Gene Chun Kwan Leung and published by . This book was released on 2020 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation studies the properties of outflows driven by active galactic nuclei (AGNs) and their impact on the evolution of galaxies. AGNs are predicted by theoretical models of galaxy formation to provide the necessary feedback to produce realistic galaxies. In theoretical models, AGNs provide feedback by driving outflows that remove gas from the host galaxy, thereby quenching star formation in massive galaxies and producing scaling relations between supermassive black holes and galaxies. Despite being indispensable in theory, critical open questions remain for AGN-driven outflows from an observational perspective. This dissertation first presents two studies using data from the MOSDEF survey, a large spectroscopic survey of galaxies when the Universe was about 3.5 billions years old (z~2). The first study focuses on the incidence and physical properties of AGN-driven outflows at z~2. We show that AGN-drive outflows are at least as prevalent at z~2 as they are in the local Universe. They are fast and extend to distances comparable to the size of the host galaxy. Using emission line ratio diagnostics, we find our data consistent with the picture of negative AGN feedback, where AGN-driven outflows suppress star formation, and find no evidence of galaxy-wide positive AGN feedback. The second study focuses on the demographics of galaxies hosting AGN-driven outflows and the relation between outflow properties and the galaxy and AGN population at z~2. We show that AGN-driven outflows are a ubiquitous phenomenon occurring across the galaxy population and in different phases of galaxy evolution, both before and after quenching. By measuring the energetics and correlations of AGN-driven outflows, we find that the outflows are more energetic at z~2 than in the local Universe, where AGNs are more powerful on average. We find that the outflows remove gas at a rate comparable to or faster than gas is being converted into stars. This shows that AGN-driven outflows at z~2 are capable of regulating star formation in the host galaxy. The third study in this dissertation presents integral field spectroscopy of a nearby ultraluminous infrared galaxy (ULIRG) and AGN Mrk 273. The study focuses on the extended ionized gas on scales of ~20 kpc. We detect for the first time highly ionized gas in one of the extended nebula surrounding the galaxy. From this, we show that shocks contribute significantly to the ionization of the gas in the extended nebulae, mixed with AGN photoionization. Our data is compatible with theoretical models in which AGNs drive a multiphase outflow, and slower-moving extended cold gas filaments form out of a more spatially confined but faster warm outflow. Our data suggests that AGNs play an important role in ejecting gas in the ULIRG phase of galaxy evolution.
Download or read book Cosmic Magnetic Fields written by Richard Wielebinski and published by Springer Science & Business Media. This book was released on 2005-09-13 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: While magnetic fields permeate the universe on all scales, the present book is dedicated to their investigation on the largest scales and affords a balanced account of both theoretical and observational aspects. Written as a set of advanced lectures and tutorial reviews that lead up to the forefront of research, this book offers both a modern source of reference for the experienced researchers as well as a high-level introductory text for postgraduate students and nonspecialist researchers working in related areas.
Download or read book Finite Volume Methods for Hyperbolic Problems written by Randall J. LeVeque and published by Cambridge University Press. This book was released on 2002-08-26 with total page 582 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, first published in 2002, contains an introduction to hyperbolic partial differential equations and a powerful class of numerical methods for approximating their solution, including both linear problems and nonlinear conservation laws. These equations describe a wide range of wave propagation and transport phenomena arising in nearly every scientific and engineering discipline. Several applications are described in a self-contained manner, along with much of the mathematical theory of hyperbolic problems. High-resolution versions of Godunov's method are developed, in which Riemann problems are solved to determine the local wave structure and limiters are then applied to eliminate numerical oscillations. These methods were originally designed to capture shock waves accurately, but are also useful tools for studying linear wave-propagation problems, particularly in heterogenous material. The methods studied are implemented in the CLAWPACK software package and source code for all the examples presented can be found on the web, along with animations of many of the simulations. This provides an excellent learning environment for understanding wave propagation phenomena and finite volume methods.
Download or read book Formation of Structure in the Universe written by Avishai Dekel and published by Cambridge University Press. This book was released on 1999-04-15 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: This advanced textbook provides an up-to-date and comprehensive introduction to the very active field of structure formation in cosmology. It is written by eleven world-leading authorities. Written in a clear and pedagogical style appropriate for graduate students in astronomy and physics, this textbook introduces the reader to a wide range of exciting topics in contemporary cosmology: from recent advances in redshift surveys, to the latest models in gravitational lensing and cosmological simulations. The authors are all world-renowned experts both for their research and teaching skills. In the fast-moving field of structure formation, this book provides advanced undergraduate and graduate students with a welcome textbook which unites the latest theory and observations.
Download or read book Exploring the Universe with the IUE Satellite written by Y. Kondo and published by Springer Science & Business Media. This book was released on 2013-12-11 with total page 769 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book was conceived to commemorate the continuing success of the guest observer program for the International Ultraviolet Explorer (IUE) satellite observatory. It is also hoped that this volume will serve as a useful tutorial for those pursuing research in related fields with future space observatories. As the IUE has been the product of the three-way collaboration between the U.S. National Aeronautics and Space Administration (NASA), European Space Agency (ESA) and the British Engineering and Research Council (SERC), so is this book the fruit of the collaboration of the American and European participants in the IUE. As such, it is a testimony to timely international cooperation and sharing of resources that open up new possibilities. The IUE spacecraft was launched on the 26th of January in 1978 into a geosynchronous orbit over the Atlantic Ocean. The scientific operations of the IUE are performed for 16 hours a day from Goddard Space Flight Center in Greenbelt, Maryland, U.S.A, and for 8 hours a day from ESA Villafranca Satellite Tracking Station near Madrid, Spain.
Download or read book Mass Outflows from Stars and Galactic Nuclei written by Luciana Bianchi and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this workshop was to put together observational and theoretical works on outflows from different kinds of astrophysical objects, occurring on different scales and at various evolutionary phases, and to discuss the impact of observations from future space missions. For the stars, we thought to follow throughout the evolution the relevance (rates and dynamical rrodes) of the mass loss phenomenon, e. g. to explain how and when massive stars loose most of their ini tial mass to end up with typical WD masses. The observations of the solar wind were included for being a unique case where the origin and propagation of the outflow can be resolved. We thought that the comparison with similar phenomena occurring in galactic outflows would be fruitful, as demonstrated by recent works on galactic winds and jets. The interest of having this workshop in Torino came because there are groups in this area, at the Astronomical Observatory and at the Institute of Physics of the University, involved in the theoretical and observational studies of outflows from astrophysical objects. The members of the Scientific Organizing Conmi ttee were: V. Castellani, C. Cesarski, P. Conti, A. Ferrari, A. Gabriel, M. Grewing, Y. Kondo, H. Lamers, V. Manno, M. Rees and R. Schilizzi. The Local Organizing Conmi ttee was: L. Bianchi, G. Massone and E. Antonucci. During the workshop the following topics were treated: the solar wind, the mass loss from cool stars and from hot stars (m. s.
Download or read book Origins of Life Volume II written by Vladivoj Valkovic and published by CRC Press. This book was released on 2024-09-27 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Origins of Life Volume II, life and its origin are inspected from traditional and unexpected points of view. The book takes an interdisciplinary approach, discussing astrobiology; chemical evolution; and how the Universe accommodates life, molecular biology, and philosophy. It is an open-minded approach, fully referenced throughout, and each chapter includes a further reading section for anyone wishing to learn more about that perspective on the origins of life. First, everything started, with the Big Bang, from nothing. It appears now that everything was aiming toward our existence, some 13.75 × 109 years later, being capable of understanding it all. We did it using powerful tools: science, philosophy, and religion. Although we appreciate the contributions made by philosophy and religion, our contemplations and doubts are based on the plentiful scientific evidence provided. The reader will be guided from make-up of the "life stage" (Universe), tools and materials needed for the living matter to be formed in the small part of the Universe, which one could call Human Neighborhood, or the Local Universe. It contains galaxies, galaxy clusters, and voids, and the Milky Way and its satellites influencing each other during this time span. The book is easy to read, accompanied by numerous references; it could be of use to the expert in the field as well as for curious minds with a scientific, philosophical, or religious background.
