Download or read book Examining the Growth and Evolution of Magnetic Fields in Clusters of Galaxies a Numerical Perspective written by Paul M. Sutter and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic fields are ubiquitous in galaxy cluster atmospheres and have a variety of astrophysical and cosmological consequences. Magnetic fields can contribute to the pressure support of clusters, affect thermal conduction, and modify the evolution of bubbles driven by active galactic nuclei. However, we currently do not fully understand the origin and evolution of these fields throughout cosmic time. Furthermore, we do not have a general understanding of the relationship between magnetic field strength and topology and other cluster properties, such as mass and X-ray luminosity. We can now begin to answer some of these questions using large-scale cosmological magnetohydrodynamic (MHD) simulations of the formation of galaxy clusters including the seeding and growth of magnetic fields. Using large-scale cosmological simulations with the FLASH code combined with a simplified model of the acceleration of cosmic rays responsible for the generation of radio halos, we find that the galaxy cluster frequency distribution and expected number counts of radio halos from upcoming low-frequency sur- veys are strongly dependent on the strength of magnetic fields. Thus, a more complete understanding of the origin and evolution of magnetic fields is necessary to understand and constrain models of diffuse synchrotron emission from clusters. One favored model for generating magnetic fields is through the amplification of weak seed fields in active galactic nuclei (AGN) accretion disks and their subsequent injection into cluster atmospheres via AGN-driven jets and bubbles. However, current large-scale cosmological simulations cannot directly include the physical processes associated with the accretion and feedback processes of AGN or the seeding and merging of the associated SMBHs. Thus, we must include these effects as subgrid models. In order to carefully study the growth of magnetic fields in clusters via AGN-driven outflows, we present a systematic study of SMBH and AGN subgrid models. Using dark-matter only cosmological simulations, we find that many important quantities, such as the relationship between SMBH mass and galactic bulge velocity dispersion and the merger rate of black holes, are highly sensitive to the subgrid model assumptions of SMBHs. In addition, using MHD calculations of an isolated cluster, we find that magnetic field strengths, extent, topology, and relationship to other gas quantities such as temperature and density are also highly dependent on the chosen model of accretion and feedback. We use these systematic studies of SMBHs and AGN inform and constrain our choice of subgrid models, and we use those results to outline a fully cosmological MHD simulation to study the injection and growth of magnetic fields in clusters of galaxies. This simulation will be the first to study the birth and evolution of magnetic fields using a fully closed accretion-feedback cycle, with as few assumptions as possible and a clearer understanding of the effects of the various parameter choices.
Download or read book Galactic and Intergalactic Magnetic Fields written by Ulrich Klein and published by Springer. This book was released on 2014-11-05 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This course-tested textbook conveys the fundamentals of magnetic fields and relativistic plasma in diffuse cosmic media, with a primary focus on phenomena that have been observed at different wavelengths. Theoretical concepts are addressed wherever necessary, with derivations presented in sufficient detail to be generally accessible. In the first few chapters the authors present an introduction to various astrophysical phenomena related to cosmic magnetism, with scales ranging from molecular clouds in star-forming regions and supernova remnants in the Milky Way, to clusters of galaxies. Later chapters address the role of magnetic fields in the evolution of the interstellar medium, galaxies and galaxy clusters. The book is intended for advanced undergraduate and postgraduate students in astronomy and physics and will serve as an entry point for those starting their first research projects in the field.
Download or read book Magnetic Fields in Galaxy Clusters written by Aurora Simionescu and published by GRIN Verlag. This book was released on 2009-01-21 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bachelor Thesis from the year 2005 in the subject Astronomy, grade: 1,0, University of Bremen, 14 entries in the bibliography, language: English, abstract: An adaptive mesh refinement simulation of galaxy cluster formation was performed that included the passive evolution of a magnetic field. It was found that structure formation plays an important role in amplifying large-scale magnetic fields and that the magnetic properties of the obtained cluster were in good agreement with recent observations. The initial field was amplified by a factor of up to 1000 during the formation of the cluster, and the field strength was seen to be well correlated with the gas density. We further found a magnetic energy power spectrum that is well described by -5/3 Kolmogorov-type turbulence. Near the accretion shocks on the outskirts of the cluster, the magnetic field is amplified well beyond the value expected from mere compression of gas. Here, shear flows lead to a substantial increase in field strength. Realistic Faraday rotation measures were obtained from the simulation data, which was however not resolved well-enough to allow for a more quantitative analysis.
Download or read book Magnetic Fields of Galaxies written by A.A. Ruzmaikin and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetism, when extended beyond normal frameworks into cosmic space is characterized by an enormous spatial scale. Because of their large sizes the nature of magnets such as the Earth and the Sun is entirely different from the nature of a horseshoe magnet. The source of cosmic magnetism is associated with the hydrodynamic motions of a highly conductive medium. In this aspect, cosmic magnets resemble a dynamo. However, currents in the dynamo flow along properly ordered wires, while chaotic, turbulent motions are dominant inside stars and liquid planetary cores. This makes more intriguing and surprising the fact that these motions maintain a regular magnetic field. Maintenance of magnetic fields is even more impressive in huge magnets, i.e. galaxies. In fact, we are living inside a giant dynamo machine, the Milky Way galaxy. Although the idea of the global magnetic field of our Galaxy was clearly proposed almost 40 years ago, firm observational evidence and definite theoretical concepts of galactic magnetism have been developed only in the last decade. This book is the first attempt at a full and consistent presentation of this problem. We discuss both theoretical views on the origin of galactic magnetism and the methods of observational study. Previous discussions were on the level of review articles or separate chapters in monographs devoted to cosmic magnetic fields (see, e.g., H. K. Moffatt, 1978, E. N. Parker, 1979 and Zeldovich et aI., 1983).
Download or read book Astrophysical Magnetic Fields written by Anvar Shukurov and published by Cambridge University Press. This book was released on 2021-12-16 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic fields permeate space and affect many major astrophysical phenomena, but they are often ignored due to their perceived complexity. This self-contained introduction to astrophysical magnetic fields provides both a comprehensive review of the current state of the subject and a critical discussion of the latest research. It presents our knowledge of magnetic fields from the Early Universe, their evolution in cosmic time through to their roles in present-day galaxies, galaxy clusters and the wider intergalactic medium, with attention given to both theory and observations. This volume also contains an extensive introduction into magnetohydrodynamics, numerous worked examples, observational and mathematical techniques and interpretations of the observations. Its review of our current knowledge, with an emphasis on results that are likely to form the basis for future progress, benefits a broad audience of advanced students and active researchers, including those from fields such as cosmology and general relativity.
Download or read book Magnetic Fields in Galaxies written by F. Krause and published by CRC Press. This book was released on 1990 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents the proceedings of the Workshop on Magnetic Fields in Galaxies, which was held in Potsdam (GDR) in the autumn of 1988.
Download or read book The Coevolution of Magnetic Fields and Galaxies in Different Environments written by Anna Williams and published by . This book was released on 2018 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic fields pervade the universe. They are observed on all astrophysical scales, from planets to the intracluster medium. Despite their ubiquity, the origin and evolution of magnetic fields remains an outstanding question in astrophysics. In this thesis, I present new observations towards the construction of the cosmological timeline of magnetic field evolution. With the Westerbork Synthesis Radio Telescope, I probe a new physical depth into the magnetic field structure of the nearside halo of spiral galaxy NGC 6946. By combining these data with previous observations at other frequencies, I model the magnetic field structure along the line of sight from the midplane to the halo. I find that the galaxy is best described by a clumpy turbulent medium that extends from the midplane to the thick synchrotron disk (~1 kpc), and estimate the scale and strength of the turbulent fields in the halo. From the isolated NGC 6946, I move to the loose galaxy group, NGC 2563, to study the magnetic fields in the intragroup medium. By comparing the Faraday rotation of distant sources behind NGC 2563 to the rotation measures of sources with sightlines surrounding it, I am unable to detect signs of large-scale fields as was previously observed in galaxy clusters. I show evidence for a radial decrease in the Faraday dispersion, as well as an increase in the magnitude of the Faraday rotation with impact distance to a known galaxy member. These last two observations suggest the presence of magnetic fields in the intragroup medium as well as a mechanism for magnetizing that medium. Lastly, I present new observations of the Faraday rotation of 149 QSOs at 0.6
Download or read book Cosmic Magnetic Fields written by Philipp P. Kronberg and published by Cambridge University Press. This book was released on 2016-10-13 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic fields are important in the Universe and their effects contain the key to many astrophysical phenomena that are otherwise impossible to understand. This book presents an up-to-date overview of this fast-growing topic and its interconnections to plasma processes, astroparticle physics, high energy astrophysics, and cosmic evolution. The phenomenology and impact of magnetic fields are described in diverse astrophysical contexts within the Universe, from galaxies to galaxy clusters, the filaments and voids of the intergalactic medium, and out to the largest redshifts. The presentation of mathematical formulae is accessible and is designed to add insight into the broad range of topics discussed. Written for graduate students and researchers in physics, astrophysics and related disciplines, this volume will inspire readers to devise new ways of thinking about magnetic fields in space on galaxy scales and beyond.
Download or read book Probing Magnetic Fields in Clusters of Galaxies written by Tracy E. Clarke and published by . This book was released on 2000 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cosmic Magnetism written by Percy Seymour and published by CRC Press. This book was released on 1986 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of extraterrestrial magnetic fields is a relatively new one, confirmation of the existance of the first such field (that of our Sun) having come a s late as 1908. In the past 30 years a great ammount of knowledge has been accumulated on Cosmic Magnetism, which has turned out to be a truly fascinating topic for study. Percy Seymour's book is the first to deal with the topic in a non-mathematical way, and he offers a fine introduction to his subject. The first three chapters consolidate our knowledge on magnetism in general and the magnetic field of the Earth, as well as discussing the reasons for studying astronomy and cosmic magnetism in particular. The remainder of the book is devoted to the main areas of cosmic magnetism - solar, plantetary and interplanetary fields, fields in stars and pulsars, fields of the milky way and fields in other galaxies. Cosmic Magnetism in an ideal book for sixth-formers and undergraduates studying physics or astronomy and will also appeal to amateur astronomers. as previous work on this topic has been 'hidden' in specialised academic journals.
Download or read book Origin and Evolution of Cosmic Magnetic Fields written by Sharanya Sur and published by Mohammed Abdul Malik. This book was released on 2024-04-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic fields are ubiquitous in the universe and their study forms an important area of research in modern day astrophysics. Starting from planetary magnetic fields like the one of the Earth, magnetic fields are found to exist in stars like the Sun, in galaxies to clusters of galaxies. The importance of magnetic fields for our understanding of the Universe has been appreciated since mid-1950's when the advent of radio astronomy and the studies of cosmic ray propagation and confinement revealed a Universe filled with thermal and relativistic plasma whose motions are controlled by magnetic fields. Indeed, cosmic magnetic fields play a crucial role in a number of physical processes in the universe from confining cosmic rays, controlling star formation, driving turbulence in accretion discs, to the production and collimation of jets in AGN's. An extensive review of astrophysical magnetic fields incorporating recent results are in Brandenburg and Subramanian(2005a). Let us first have a quick look into the estimates of the strength and coherence scales of magnetic fields in some astrophysical objects. The magnetic field of the Sun consists of large-scale and small-scale components. The magnetic field of the Sun consists of large-scale and small-scale components. The typical length scale associated with the large-scale field is the width of the toroidal flux belts with the same polarity around the 30° latitude corresponding to about 300 Mm (1Mm = 1000 km). The pressure scale height at the bottom of the convection zone is about 50 Mm and scales smaller than this is associated with the small-scale field.
Download or read book Magnetic fields in clusters of galaxies written by Federica Govoni and published by . This book was released on 2001* with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galactic and Intergalactic Magnetic Fields written by R. Beck and published by Springer. This book was released on 1990-05-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Symposium, the first devoted entirely to the measurement and the role of magnetic fields in the non-solar Universe, was held in Heidelberg, on June 19-23, 1989. The meeting began with review talks on magnetic phenomena near the solar photosphere, corona, and in stellar winds, since these nearby "laboratories", studied for many years, provide much of the prior knowl edge of magnetic effects in astrophysical plasmas. The Symposium contained presentations of considerable new work concerning the role of magnetic fields in accretion disks, bipolar outflows, and related magnetic phenomena in molecular clouds and star forming regions. Both observa tions and related theory of the large-scale magnetic fields in the Milky Way were covered, in addition to a session on the more general theme of magnetohydrodynamics of galactic magnetic fields. Dynamo mechanisms were discussed in considerable detail. It was apparent that recent observational data on polarized emission from external galaxies are now of sufficiently high quality that meaningful tests of large-scale field amplification, and of ideas on the origin of galactic magnetic fields, can be undertaken. Both new observations and numerical simulation work were described in the context of active galaxy nuclei, supernova remnants, radio source jets and extended lobes, and also in the environment of galaxy clusters. Recent large-scale computer simulations incorporating magnetic fields in star formation, radio source jets, and many other phenomena were presented, and much of this was very new.
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 Large scale Magnetic Fields in the Universe written by Rainer Beck and published by Springer. This book was released on 2012-11-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A collection of sixteen coordinated reviews on the origins of large-scale magnetic fields in the Universe, this book discusses magnetic fields in all relevant astrophysical contexts, from the interstellar medium to the scales of galaxies and clusters of galaxies. Magnetic fields are described in their very diverse environments, from stellar winds to galactic haloes and astrophysical jets; together with the roles they play in forming the structures and shaping the dynamics of these objects. Both observational evidence and its theoretical interpretations are covered up to the largest scales in the Universe. The authors are all leading scientists in their fields, making this book an authoritative, up-to-date and enduring contribution to astrophysics. This volume is aimed at graduate students and researchers in astrophysics. Previously published in Space Science Reviews journal, Vol. 166/1-4 and Vol. 169/1-4, 2012.
Download or read book Galactic and Intergalactic Magnetic Fields written by R. Beck and published by Springer. This book was released on 1990-04-30 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Symposium, the first devoted entirely to the measurement and the role of magnetic fields in the non-solar Universe, was held in Heidelberg, on June 19-23, 1989. The meeting began with review talks on magnetic phenomena near the solar photosphere, corona, and in stellar winds, since these nearby "laboratories", studied for many years, provide much of the prior knowl edge of magnetic effects in astrophysical plasmas. The Symposium contained presentations of considerable new work concerning the role of magnetic fields in accretion disks, bipolar outflows, and related magnetic phenomena in molecular clouds and star forming regions. Both observa tions and related theory of the large-scale magnetic fields in the Milky Way were covered, in addition to a session on the more general theme of magnetohydrodynamics of galactic magnetic fields. Dynamo mechanisms were discussed in considerable detail. It was apparent that recent observational data on polarized emission from external galaxies are now of sufficiently high quality that meaningful tests of large-scale field amplification, and of ideas on the origin of galactic magnetic fields, can be undertaken. Both new observations and numerical simulation work were described in the context of active galaxy nuclei, supernova remnants, radio source jets and extended lobes, and also in the environment of galaxy clusters. Recent large-scale computer simulations incorporating magnetic fields in star formation, radio source jets, and many other phenomena were presented, and much of this was very new.
Download or read book The AGN Origin of Cluster Magnetic Fields written by Hao Xu and published by . This book was released on 2009 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin of magnetic fields in galaxy clusters is one of the most fascinating but challenging problems in astrophysics. In this dissertation, the possibility of an Active Galactic Nucleus (AGN) origin of cluster magnetic fields is studied through state of the art simulations of magnetic field evolution in large scale structure formation using a newly developed cosmological Adaptive Mesh Refinement (AMR) Magnetohydrodynamics (MHD) code -- EnzoMHD. After presenting a complete but concise description and verification of the code, we discuss the creation of magnetic fields through the Biermann Battery effect during first star formation and galaxy cluster formation. We find that magnetic fields are produced as predicted by theory in both cases. For the first star formation, we obtain a lower limit of (~ 10−9 G) for magnetic fields when the first generation stars form. On the other hand, we find that the magnetic energy is amplified 4 orders of magnitude within ~ 10 Gyr during cluster formation. We then study magnetic field injection from AGN into the Intra-Cluster Medium (ICM) and their impact on the ICM. We reproduce the X-ray cavities as well as weak shocks seen in observations in the simulation, and further confirm the idea that AGN outburst must contain lots of magnetic energy (up to 1061 ergs) and the magnetic fields play an important part in the formation of jet/lobe system. We present high resolution simulations of cluster formation with magnetic fields injected from high redshift AGN. We find that these local magnetic fields are spread quickly throughout the whole cluster by cluster mergers. The ICM is in a turbulent state with a Kolmogorov-like power spectrum. Magnetic fields are amplified to and maintained at the observational level of a few [mu]G by bulk flows at large scale and the ICM turbulence at small scale. The total magnetic energy increases about 25 times to ~ 1.2 x 10
