Download or read book Illuminating The Star Clusters And Dwarf Galaxies by Multi scale Baryonic Simulations written by Moupiya Maji and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade, advances in computational architecture have made it possiblefor the first time to investigate some of the fundamental questions around the birthand the growth of the building blocks of the universe; star clusters and galaxies. Inthese stellar and star-forming systems, baryonic physics play an important role indetermining their formation and evolution. Therefore, in my research, I have exploredstar-forming systems using high resolution baryonic cosmological simulations andexplored the origin of star clusters, anisotropic spatial distribution of satellite galaxiesand the effect of reionization on the evolution of dwarf galaxies.Observations of globular clusters show that they have universal lognormal massfunctions with a characteristic peak at 2 10^5MSun , although the origin of this peakeddistribution is unclear. Here I have investigated the formation and evolution of starclusters (SCs) in interacting galaxies using high-resolution hydrodynamical simulationsperformed with two different codes. I have found that massive star clusters in therange of 10^5.5 10^7.5 MSun form preferentially in extremely high-pressure gas cloudsin highly-shocked regions produced by galaxy interactions. These findings provide thefirst simulation confirmation of the analytical theory of high pressure induced clusterformation. Furthermore, these massive star clusters have quasi-lognormal initial massfunctions with a peak around 106 M . The number of clusters declines with timedue to destructive processes, but the shape and the peak of the mass functions do notchange significantly during the course of galaxy collisions. These results suggest thatgas-rich galaxy mergers provide a favorable environment for the formation of globularclusters and that the lognormal mass functions and the unique peak may originatefrom the extreme high-pressure conditions of the birth clouds and may survive thedynamical evolution.Observations of classical Milky Way satellites suggest that they are aligned in aplane inclined to the Galactic stellar disk, a phenomenon which later became knownas the disk of satellites(DoS). However, N-body simulations of galaxies predict anisotropic distribution of subhalos around the host galaxy and this discrepancy hasbeen strongly criticized as a failure of CDM. In this thesis, I have explored this highlydebated topic by reanalyzing the observations and exploring the satellite distributions in high-resolution baryonic simulations. In particular, I have demonstrated that asmall sample size can artificially produce a highly anisotropic spatial distributionand a strong clustering of the angular momenta of the satellites and have shownthat the current Milky way DoS is transient. Furthermore, I have analyzed twocosmological simulations using the same initial conditions of a Milky-Way-sizedgalaxy, an N-body run with dark matter only, and a hydrodynamic one with bothbaryonic and dark matter, and found that the hydrodynamic simulation producesa more anisotropic distribution of satellites than the N-body one. These resultssuggest that an anisotropic distribution of satellites in galaxies can originate frombaryonic processes in the hierarchical structure formation model, but the claimedhighly flattened, coherently rotating DoS of the Milky Way may be biased by the small number selection effect. Finally, I have investigated the distribution and kinematicsof satellites around a large sample of few thousand host galaxies in the Illustrissimulation and found that the DoS become more isotropic with increasing numberof satellites and no clear coherent rotation is found in most ( 90%) of the satellitesystems. Furthermore, their overall evolution indicates that the DoS may be part oflarge scale filamentary structure. These findings can help resolve the contradictoryclaims of DoS in galaxies and show that baryonic processes may be the key to solvethe so-called small scale CDM problems.Additionally, I have also explored the effects of reionization on the star formationhistories of dwarfs galaxies, using a cosmological hydrodynamic simulation of MilkyWay and its satellite galaxies. I have found that most dwarfs are extremely old systemsand star formation is quenched earlier in lower mass galaxies. During reionization,most of the lower mass dwarfs are destroyed while the remaining massive dwarfsbecome severely baryon deficient. The dwarf galaxies play a very important role inshaping the path of cosmic history, especially in terms of reionization. Observingand studying the ultra-faint dwarfs hold the key to understanding the physics of earlyuniverse in great depth.
Download or read book The Local Group and Its Dwarf Galaxy Members in the Standard Model of Cosmology written by Azadeh Fattahi and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: According to the current cosmological paradigm, ``Lambda Cold Dark Matter'' (LambdaCDM), only ~20% of the gravitating matter in the universe is made up of ordinary (i.e. baryonic) matter, while the rest consists of invisible dark matter (DM) particles, which existence can be inferred from their gravitational influence on baryonic matter and light. Despite the large success of the LambdaCDM model in explaining the large scale structure of the Universe and the conditions of the early Universe, there has been debate on whether this model can fully explain the observations of low mass (dwarf) galaxies. The Local Group (LG), which hosts most of the known dwarf galaxies, is a unique laboratory to test the predictions of the LambdaCDM model on small scales. I analyze the kinematics of LG members, including the Milky~Way-Andromeda (MW-M31) pair and dwarf galaxies, in order to constrain the mass of the LG. I construct samples of LG analogs from large cosmological N-body simulations, according to the following kinematics constraints: (a) the separation and relative velocity of the MW-M31 pair; (b) the receding velocity of dwarf galaxies in the outskirts of the LG. I find that these constraints yield a median total mass of 2*10^#x12; solar masses for the MW and M31, but with a large uncertainty. Based on the mass and the kinematics constraints, I select twelve LG candidates for the APOSTLE simulations project. The APOSTLE project consists of high-resolution cosmological hydrodynamical simulations of the LG candidates, using the EAGLE galaxy formation model. I show that dwarf satellites of MW and M31 analogs in APOSTLE are in good agreement with observations, in terms of number, luminosity and kinematics. There have been tensions between the observed masses of LG dwarf spheroidals and the predictions of N-body simulations within the LambdaCDM framework; simulations tend to over-predict the mass of dwarfs. This problem is known as the ``too-big-to-fail'' problem. I find that the enclosed mass within the half-light radii of Galactic classical dwarf spheroidals, is in excellent agreement with the simulated satellites in APOSTLE, and that there is no too-big-to-fail problem in APOSTLE simulations. A few factors contribute in solving the problem: (a) the mass of haloes in hydrodynamical simulations are lower compared to their N-body counterparts; (b) stellar mass-halo mass relation in APOSTLE is different than the ones used to argue for the too-big-to-fail problem; (c) number of massive satellites correlates with the virial mass of the host, i.e. MW analogs with virial masses above ~ 3*10^#x12; solar masses would have faced too-big-to-fail problems; (d) uncertainties in observations were underestimated in previous works. Stellar mass-halo mass relation in APOSTLE predicts that all isolated dwarf galaxies should live in haloes with maximum circular velocity (V_max) above 20 km/s. Satellite galaxies, however, can inhabit lower mass haloes due to tidal stripping which removes mass from the inner regions of satellites as they orbit their hosts. I examine all satellites of the MW and M31, and find that many of them live in haloes less massive than V_max=20 km/s. I additionally show that the low mass population is following a different trend in stellar mass-size relation compared to the rest of the satellites or field dwarfs. I use stellar mass-halo mass relation of APOSTLE field galaxies, along with tidal stripping trajectories derived in Penarrubia et al., in order to predict the properties of the progenitors of the LG satellites. According to this prediction, some satellites have lost a significant amount of dark matter as well as stellar mass. Cra~II, And~XIX, XXI, and XXV have lost 99 per-cent of their stellar mass in the past. I show that the mass discrepancy-acceleration relation of dwarf galaxies in the LG is at odds with MOdified Newtonian Dynamics (MOND) predictions, whereas tidal stripping can explain the observations very well. I compare observed velocity dispersion of LG satellites with the predicted values by MOND. The observations and MOND predictions are inconsistent, in particular in the regime of ultra faint dwarf galaxies.
Download or read book A unified formation scenario for the zoo of extended star clusters and ultra compact dwarf galaxies written by Renate Claudia Brüns and published by . This book was released on 2014 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bang to Eternity and Betwixt written by John Hussey and published by John Hussey. This book was released on 2014-07-31 with total page 3555 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering the Cosmos from before the Big Bang through to the creation of our universe and up to but not including our arrival on stage; our will is not yet imposed, we had no hand, act nor part in its provisions, beyond investigating to understand what has been delivered us. The many aspects of the Cosmos are melded, in a headline driven style, to paint a cohesive picture as well as allowing the reader choose to delve further where they may choose to paint their personal picture. Cosmos – includes; • The creation mechanism for our Universe and why there exists a possible Multiverse. • The creation mechanisms of the galaxies with their diversity of Star types. • The space exploration of our Solar System. • The Earth and Moon from their birth to their life driving engines for our planet. • The evolutionary processes that led to our arrival on the planet. • Our natural world with its great events. • Documentary video links on all topics of the book are included. The story is factual in manner, in the proper tradition of reporting, no personal opinions are expressed. The life stories of the standout personalities, in text and video, without whom what is now known, could not have been unraveled, in the case of Cosmos, they are; • Galileo Galilei • Isaac Newton • Albert Einstein • Charles Darwin This is a Video Book, vBook, beyond its text there are 150+ video titles, 100+ viewing hours, downloaded and stored locally on your computer, to be able to watch anytime, offline, without the need for local internet connection. Google ‘Cosmos’ and you get about 27,800,000 search results, so over these last several years I’ve searched out the best documentary videos with their hyperlinks included here, blending their content to report cohesively, supplementing, where appropriate, from Wikipedia and also include those hyperlinks for readers wanting to delve further. The ‘List of Contents’ runs to 6 levels to provide a form of map to the reader as the reporting sequence is not a mere chronology of Cosmic events, it delves, as necessary into the stories as to how the events became understood to us. There is a 7th level, hyperlinked, at its base, which brings further background content, from Wikipedia, to those who choose to read further into any of the topics. The ‘Index’ allows navigation for the reader who has specific interests to investigate through the fabric of the report. The ‘Text’ is structured to 4 levels beginning with the primary, headline driven, main body content followed by relevant Wikipedia extracts, indented in purple, for those choosing to read further into a particular topic through to hyperlinked Wikipedia - Full Article text within the book and in turn out to the website itself. For the reader that wants to stay with the big picture, main body content, there is a “Skip” link to take you past each of the extracts, on to the next headline title and main body content. There are 150+ video content links delivering 100+ hours of viewing time, of the best documentary film available online. The main sequence structure is; • Cosmology – Universe & Multiverse • Geology – Earth & Moon • Biology – Life – Plant & Animal • Ecology – Evolution & Environment – Plant, Animal & Human Special Edition There is also a Special Edition of this book available for US$49.95 which streams all video content from a secure Cloud Drive; therefore, video content cannot be removed by third party video platform providers such as YouTube, DailyMotion, Vimeo….. This Standard Edition streams from these. The Cloud Drive Server also allows you conveniently download to your local drive, as much video content as you choose, to watch, offline, at a time that best suits you. To view or purchase, paste the books ASIN: B00LEWY5WW into the Kindle Store search box. If you've any queries, feel welcome to contact [email protected]
Download or read book New Worlds New Horizons in Astronomy and Astrophysics written by National Research Council and published by National Academies Press. This book was released on 2011-02-04 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Driven by discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically during the course of the last few decades. The fields of astronomy and astrophysics are making new connections to physics, chemistry, biology, and computer science. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics outlines a plan for ground- and space- based astronomy and astrophysics for the decade of the 2010's. Realizing these scientific opportunities is contingent upon maintaining and strengthening the foundations of the research enterprise including technological development, theory, computation and data handling, laboratory experiments, and human resources. New Worlds, New Horizons in Astronomy and Astrophysics proposes enhancing innovative but moderate-cost programs in space and on the ground that will enable the community to respond rapidly and flexibly to new scientific discoveries. The book recommends beginning construction on survey telescopes in space and on the ground to investigate the nature of dark energy, as well as the next generation of large ground-based giant optical telescopes and a new class of space-based gravitational observatory to observe the merging of distant black holes and precisely test theories of gravity. New Worlds, New Horizons in Astronomy and Astrophysics recommends a balanced and executable program that will support research surrounding the most profound questions about the cosmos. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed. The book is a useful resource for agencies supporting the field of astronomy and astrophysics, the Congressional committees with jurisdiction over those agencies, the scientific community, and the public.
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 Galaxies in the Local Volume written by Bärbel Silvia Koribalski and published by Springer Science & Business Media. This book was released on 2009-04-29 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: This timely book presents an overview of the galaxies within the Local Volume, including the Local Group and our closest neighbours, the Andromeda Galaxy and the Magellanic Clouds. Presented here are the latest results from radio, infrared and optical surveys as well as detailed multi-wavelength studies of individual galaxies. The book aims to provide a vibrant forum for presentations and discussions across a broad range of astrophysical topics.
Download or read book A Philosophical Approach to MOND written by David Merritt and published by Cambridge University Press. This book was released on 2020-04-30 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dark matter is a fundamental component of the standard cosmological model, but in spite of four decades of increasingly sensitive searches, no-one has yet detected a single dark-matter particle in the laboratory. An alternative cosmological paradigm exists: MOND (Modified Newtonian Dynamics). Observations explained in the standard model by postulating dark matter are described in MOND by proposing a modification of Newton's laws of motion. Both MOND and the standard model have had successes and failures – but only MOND has repeatedly predicted observational facts in advance of their discovery. In this volume, David Merritt outlines why such predictions are considered by many philosophers of science to be the 'gold standard' when it comes to judging a theory's validity. In a world where the standard model receives most attention, the author applies criteria from the philosophy of science to assess, in a systematic way, the viability of this alternative cosmological paradigm.
Download or read book Galactic Dynamics written by James Binney and published by Princeton University Press. This book was released on 2011-10-30 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since it was first published in 1987, Galactic Dynamics has become the most widely used advanced textbook on the structure and dynamics of galaxies and one of the most cited references in astrophysics. Now, in this extensively revised and updated edition, James Binney and Scott Tremaine describe the dramatic recent advances in this subject, making Galactic Dynamics the most authoritative introduction to galactic astrophysics available to advanced undergraduate students, graduate students, and researchers. Every part of the book has been thoroughly overhauled, and many sections have been completely rewritten. Many new topics are covered, including N-body simulation methods, black holes in stellar systems, linear stability and response theory, and galaxy formation in the cosmological context. Binney and Tremaine, two of the world's leading astrophysicists, use the tools of theoretical physics to describe how galaxies and other stellar systems work, succinctly and lucidly explaining theoretical principles and their applications to observational phenomena. They provide readers with an understanding of stellar dynamics at the level needed to reach the frontiers of the subject. This new edition of the classic text is the definitive introduction to the field. ? A complete revision and update of one of the most cited references in astrophysics Provides a comprehensive description of the dynamical structure and evolution of galaxies and other stellar systems Serves as both a graduate textbook and a resource for researchers Includes 20 color illustrations, 205 figures, and more than 200 problems Covers the gravitational N-body problem, hierarchical galaxy formation, galaxy mergers, dark matter, spiral structure, numerical simulations, orbits and chaos, equilibrium and stability of stellar systems, evolution of binary stars and star clusters, and much more Companion volume to Galactic Astronomy, the definitive book on the phenomenology of galaxies and star clusters
Download or read book The First Stars written by Volker Bromm and published by Springer. This book was released on 2016-09-07 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of the first stars (Pop III stars) and galaxies is one of the great outstanding challenges in modern astrophysics and cosmology. The first stars are likely key drivers for early cosmic evolution and will be at the center of attention over the next decade. The best available space and ground-based telescopes like the Hubble Space Telescope probe the Universe to high redshifts and provide us with tantalizing hints; but they cannot yet directly detect the first generation of stars and the formation of the first galaxies. This is left as key science for future telecopes like the James Webb Space Telescope. This book is based in part on classroom tested lectures related to Pop III stars, but also draws from the author's review articles of the main physical principles involved. The book will thus combine pedagogical introductory chapters with more advanced ones to survey the cutting-edge advances from the frontier of research. It covers the theory of first star formation, the relation between first stars and dark matter, their impact on cosmology, their observational signatures, the transition to normal star formation as well as the assembly of the first galaxies. It will prepare students for interpreting observational findings and their cosmological implications.
Download or read book The Formation of the Milky Way written by E. J. Alfaro and published by Cambridge University Press. This book was released on 1995-08-03 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This review examines all the key physical processes involved in the formation and evolution of the Milky Way, based on an international meeting held in Granada (Spain).
Download or read book The Origin of the Galaxy and Local Group written by Joss Bland-Hawthorn and published by Springer Science & Business Media. This book was released on 2014-02-11 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the updated and expanded lecture notes of the 37th Saas-Fee Advanced Course organised by the Swiss Society for Astrophysics and Astronomy. It offers the most comprehensive and up to date review of one of the hottest research topics in astrophysics - how our Milky Way galaxy formed. Joss Bland-Hawthorn & Ken Freeman lectured on Near Field Cosmology - The Origin of the Galaxy and the Local Group. Francesca Matteucci’s chapter is on Chemical evolution of the Milky Way and its Satellites. As designed by the SSAA, books in this series – and this one too – are targeted at graduate and PhD students and young researchers in astronomy, astrophysics and cosmology. Lecturers and researchers entering the field will also benefit from the book.
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 Unveiling Galaxies written by Jean-René Roy and published by Cambridge University Press. This book was released on 2018 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: A thought provoking study of the powerful impact of images in guiding astronomers' understanding of galaxies through time.
Download or read book 3D Spectroscopy of Dense Stellar Populations written by Tim-Oliver Husser and published by Universitätsverlag Göttingen. This book was released on 2012 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Globular clusters are gravitationally bound collections of hundreds of thousands of stars that are almost as old as the Universe itself. Although they have been studied for hundreds of years, their formation and evolution is not yet fully understood. We want to fi nd answers to some of the major questions by investing a large amount of observing time with MUSE, the upcoming 2nd generation instrument for ESOś Very Large Telescope. In this thesis I discuss the current state of research on globular clusters as well as the possibilities of this new instrument. Numerical methods for the analysis of MUSE data are presented, including a comprehensive library of synthetic spectra that has been created just for this purpose. The application of these methods to both synthetic and real data is discussed with particular emphasis on a "dry run" that has been conducted for MUSE. Finally, a potential program for the observation of globular clusters is presented.
Download or read book Study Week on Nuclei of Galaxies April 13 18 1970 written by D. J. K. O'Connell and published by . This book was released on 1971 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Cosmology written by Barbara Ryden and published by Cambridge University Press. This book was released on 2017 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: A substantial update of this award-winning and highly regarded cosmology textbook, for advanced undergraduates in physics and astronomy.
