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The last 50 years have seen a tremendous progress in the research on quasars. From a time when quasars were unforeseen oddities, we have come to a view that considers quasars as active galactic nuclei, with nuclear activity a coming-of-age experienced by most or all galaxies in their evolution. We have passed from a few tens of known quasars of the early 1970s to the 500,000 listed in the catalogue of the Data Release 14 of the Sloan Digital Sky Survey. Not surprisingly, accretion processes on the central black holes in the nuclei of galaxies — the key concept in our understanding of quasars and active nuclei in general — have gained an outstanding status in present-day astrophysics. Accretion produces a rich spectrum of phenomena in all bands of the electromagnetic spectrum. The power output of highly-accreting quasars has impressive effects on their host galaxies. All the improvement in telescope light gathering and in computing power notwithstanding, we still miss a clear connection between observational properties and theory for quasars, as provided, for example, by the H-R diagram for stars. We do not yet have a complete self-consistent view of nuclear activity with predictive power, as we do for main-sequence stellar sources. At the same time quasars offer many “windows open onto the unknown". On small scales, quasar properties depend on phenomena very close to the black hole event horizon. On large scales, quasars may effect evolution of host galaxies and their circum-galactic environments. Quasars’ potential to map the matter density of the Universe and help reconstruct the Universe’s spacetime geometry is still largely unexploited. The times are ripe for a critical assessment of our present knowledge of quasars as accreting black holes and of their evolution across the cosmic time. The foremost aim of this research topic is to review and contextualize the main observational scenarios following an empirical approach, to present and discuss the accretion scenario, and then to analyze how a closer connection between theory and observation can be achieved, identifying those aspects of our understanding that are still on a shaky terrain and are therefore uncertain knowledge. This research topic covers topics ranging from the nearest environment of the black hole, to the environment of the host galaxies of active nuclei, and to the quasars as markers of the large scale structure and of the geometry of spacetime of the Universe. The spatial domains encompass the accretion disk, the emission and absorption regions, circum-nuclear starbursts, the host galaxy and its interaction with other galaxies. Systematic attention is devoted to some key problems that remain outstanding and are clearly not yet solved: the existence of two quasar classes, radio quiet and radio loud, and in general, the systematic contextualization of quasar properties the properties of the central black hole, the dynamics of the accretion flow in the inner parsecs and the origin of the accretion matter, the quasars’ small and large scale environment, the feedback processes produced by the black hole into the host galaxy, quasar evolutionary patterns from seed black holes to the present-day Universe, and the use of quasars as cosmological standard candles. The timing is appropriate as we are now witnessing a growing body of results from major surveys in the optical, UV X, near and far IR, and radio spectral domains. Radio instrumentation has been upgraded to linear detector — a change that resembles the introduction of CCDs for optical astronomy — making it possible to study radio-quiet quasars at radio frequencies. Herschel and ALMA are especially suited to study the circum-nuclear star formation processes. The new generation of 3D magnetohydrodynamical models offers the prospective of a full physical modeling of the whole quasar emitting regions. At the same time, on the forefront of optical astronomy, applications of adaptive optics to long-slit spectroscopy is yielding unprecedented results on high redshift quasars. Other measurement techniques like 2D and photometric reverberation mapping are also yielding an unprecedented amount of data thanks to dedicated experiments and instruments. Thanks to the instrumental advances, ever growing computing power as well as the coming of age of statistical and analysis techniques, the smallest spatial scales are being probed at unprecedented resolution for wide samples of quasars. On large scales, feedback processes are going out of the realm of single-object studies and are entering into the domain of issues involving efficiency and prevalence over a broad range of cosmic epochs. The Research Topic "Quasars at all Cosmic Epochs" collects a large fraction of the contributions presented at a meeting held in Padova, sponsored jointly by the National Institute for Astrophysics, the Padova Astronomical Observatory, the Department of Physics and Astronomy of the University of Padova, and the Instito de Astrofísica de Andalucía (IAA) of the Consejo Superiór de Investigación Cientifica (CSIC). The meeting has been part of the events meant to celebrate the 250th anniversary of the foundation of the Padova Observatory.
Active Galactic Nuclei (AGN) --- extragalactic radio sources --- spectral energy distribution of quasars --- cosmology --- black holes --- accretion disks --- evolution of galaxies
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Accretion-ejection around compact objects, mainly around black holes, both in low mass, supermassive, and intermediate-mass, are rich and has been studied exhaustively. However, the subject is expanding and growing rapidly after the launch of different space-based satellites and ground-based telescopes in multiwavelength bands, leaving a range of questions on accretion and ejection mechanisms. The proper understanding of the underlying physical mechanisms responsible for observational evidence is still lacking for several reasons. With the advent of high-resolution satellite observations, it is possible to look at the problems globally as a complete package in a more consistent way. Recently, many new low mass black hole candidates have been discovered; however, very little is known about those systems, e.g., mass, spin parameter, and orbital period. The study in the spectro-temporal domain also needs proper understanding of spectral state change, quasi-periodic oscillation frequency evolution, hardness intensity diagram, and line emissions. The goal and motivation of this book are to focus on top-quality original works in the above-mentioned context, with important research facts that are written in a highly understandable way, from a theoretical, observational, and numerical simulation ground.This book is a collection of high-quality research work, which will give a compact and concise description of the overall view of the subject.
Research & information: general --- Physics --- Astronomy, space & time --- black hole physics --- rotating black holes --- relativistic jets --- active galactic nuclei --- supermassive black holes --- radio galaxies --- galaxies: active --- galaxies: jets --- galaxies: nuclei --- radiative transfer --- Seyfert 1 objects: individual: Mrk 335 --- X-Rays:binaries—stars individual: (XTE J1908+094)—stars:black holes—accretion --- accretion disks—shock waves—radiation:dynamics --- X-rays: binaries—stars individual: (V404 Cygni)—stars:black holes—accretion --- isofrequency --- geodesic orbits --- black string --- black hole evolution --- supermassive black hole --- accretion of matter --- galaxies: evolution --- galaxies --- active --- galaxies–quasars --- individual (Ton 599) --- BL lacertae objects --- OJ 287 --- accretion discs --- gravitational waves --- jets --- blazars --- X-rays --- synchrotron emission --- inverse-Compton emission --- optical spectroscopy --- ionized gas --- broad line region --- n/a --- X-Rays:binaries-stars individual: (XTE J1908+094)-stars:black holes-accretion --- accretion disks-shock waves-radiation:dynamics --- X-rays: binaries-stars individual: (V404 Cygni)-stars:black holes-accretion --- galaxies-quasars
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This book, dedicated to Roger Penrose, is a second, mathematically oriented course in general relativity. It contains extensive references and occasional excursions in the history and philosophy of gravity, including a relatively lengthy historical introduction. The book is intended for all students of general relativity of any age and orientation who have a background including at least first courses in special and general relativity, differential geometry, and topology. The material is developed in such a way that through the last two chapters the reader may acquire a taste of the modern mathematical study of black holes initiated by Penrose, Hawking, and others, as further influenced by the initial-value or PDE approach to general relativity. Successful readers might be able to begin reading research papers on black holes, especially in mathematical physics and in the philosophy of physics. The chapters are: Historical introduction, General differential geometry, Metric differential geometry, Curvature, Geodesics and causal structure, The singularity theorems of Hawking and Penrose, The Einstein equations, The 3+1 split of space-time, Black holes I: Exact solutions, and Black holes II: General theory. These are followed by two appendices containing background on Lie groups, Lie algebras, & constant curvature, and on Formal PDE theory.
Riemannian geometry. --- Differential geometry. --- Relativity physics --- History. --- Mathematics. --- Topology. --- Mathematical physics --- Penrose --- Gravity --- Einstein --- Black holes --- Mathematical Relativity --- Geometry, Riemannian. --- Geometry, Differential. --- Relativity (Physics)
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Relativistic quantum information is one of the most exciting fields of physics today. Not only does it open possibilities for new forms of computing but it also calls into question the peaceful coexistence between classical space–time and quantum physics with scenarios that reopen the relationships between locality and nonlocality in the foundational structure of physics. Curated by two international experts Ignazio Licata and Fabrizio Tamburini, this volume hosts a selection of particularly significant essays for the new territories, and is dedicated to the 60th anniversary of Prof. Ignazio Licata.
spacetime entanglement entropy --- Unruh effect --- gravitational force --- thermodynamics --- holographic principle --- simultaneous --- classical communication --- quantum key distribution --- plug-and-play configuration --- optical amplifier --- relativistic quantum information --- quantum cryptography --- summoning --- no-cloning --- no-signalling --- bit commitment --- quantum electrodynamics --- analogue gravity --- Bose-Einstein condensation --- information loss --- cosmological particle creation --- wormholes --- entanglement --- ER = EPR --- Planck scales --- colliding black holes --- quantum hair --- bohr-likr black holes --- n/a
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General relativity is a beautiful geometric theory, simple in its mathematical formulation but leading to numerous consequences with striking physical interpretations: gravitational waves, black holes, cosmological models, and so on. This introductory textbook is written for mathematics students interested in physics and physics students interested in exact mathematical formulations (or for anyone with a scientific mind who is curious to know more of the world we live in), recent remarkable experimental and observational results which confirm the theory are clearly described and no specialised physics knowledge is required.
General relativity (Physics) --- Black holes (Astronomy) --- Gravitational waves. --- Cosmology. --- Relativité générale (Physique) --- Trous noirs (Astronomie) --- Ondes gravitationnelles --- Cosmologie --- Relativity (Physics) --- Gravitation --- Nonrelativistic quantum mechanics --- Space and time --- Special relativity (Physics) --- Science. --- Physics.
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During the past few decades, plasma science has witnessed a great growth in laboratory studies, in simulations, and in space. Plasma is the most common phase of ordinary matter in the universe. It is a state in which ionized matter (even as low as 1%) becomes highly electrically conductive. As such, long-range electric and magnetic fields dominate its behavior. Cosmic plasmas are mostly associated with stars, supernovae, pulsars and neutron stars, quasars and active galaxies at the vicinities of black holes (i.e., their jets and accretion disks). Cosmic plasma phenomena can be studied with different methods, such as laboratory experiments, astrophysical observations, and theoretical/computational approaches (i.e., MHD, particle-in-cell simulations, etc.). They exhibit a multitude of complex magnetohydrodynamic behaviors, acceleration, radiation, turbulence, and various instability phenomena. This Special Issue addresses the growing need of the plasma science principles in astrophysics and presents our current understanding of the physics of astrophysical plasmas, their electromagnetic behaviors and properties (e.g., shocks, waves, turbulence, instabilities, collimation, acceleration and radiation), both microscopically and macroscopically. This Special Issue provides a series of state-of-the-art reviews from international experts in the field of cosmic plasmas and electromagnetic phenomena using theoretical approaches, astrophysical observations, laboratory experiments, and state-of-the-art simulation studies.
cosmic ray knee and ankle --- blazars --- numerical methods --- global jets --- MHD–accretion --- muti-messenger astronomy --- massive star supernovae --- galaxies: active --- TBD --- 26Al --- black holes --- accreting black holes --- particle-in-cell simulations --- kink-like instability --- laser-induced nuclear reactions --- magnetic fields --- magneto-hydrodynamics --- gamma-ray bursts --- active galactic nuclei --- accretion discs–jets --- numerical relativity --- plasma physics --- GRMHD --- high-power laser systems --- radio interferometry --- recollimation shocks --- effective lifetime --- multi-wavelength astronomy --- relativistic jets --- high energy astrophysics --- jets --- active galaxies --- relativistic astrophysics --- helical magnetic fields --- laser plasma --- X-ray binaries --- polarization --- the Weibel instability --- AGN --- neutrino astrophysics --- radiation mechanism: non-thermal --- nuclear astrophysics --- cosmic rays --- mushroom instability --- accretion disks --- MHD winds
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"Breakthrough Prize recipient Joseph Polchinksi (now deceased) reveals details of his upbringing, his collaborations with major figures in physics, and his significant contributions to string theory and cosmology"--
Autobiography: science, technology & medicine --- Cryogenics --- History of science --- multiverse --- theory of everything --- D-branes --- string theory --- black holes --- theoretical physics --- Stephen Hawking --- holographic universe --- universe --- string theorist --- autobiography --- scientist --- Joseph Polchinski --- life of a theoretical physicist --- Physicists --- Physics --- Cosmology. --- Philosophy. --- Polchinski, Joseph Gerard. --- BIOGRAPHY & AUTOBIOGRAPHY / Science & Technology --- SCIENCE / Physics / General --- SCIENCE / History --- Astronomy --- Deism --- Metaphysics
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The year 2019 saw the centenary of Eddington's eclipse expeditions and the corroboration of Einstein's general relativity by gravitational lensing. To mark the occasion, a Special Issue of Universe has been dedicated to the theoretical aspects of strong gravitational lensing. The articles assembled in this volume contain original research and reviews and apply a variety of mathematical techniques that have been developed to study this effect, both in 3-space and in spacetime. These include: · Mathematical properties of the standard thin lens approximation, in particular caustics; · Optical geometry, the Gauss–Bonnet method and related approaches; · Lensing in the spacetime of general relativity and modified theories; black hole shadows.
gravitational lensing --- weak deflection --- dark matter --- Gauss–Bonnet theorem --- black hole --- wormhole --- strong gravitational lensing --- magnification cross sections --- caustics --- gravitational lens --- general relativity --- ultralight particles --- black hole shadow --- event horizon telescope --- rotating black hole --- global monopole --- perfect fluid --- scalar field --- shadows --- black holes --- wormholes --- galaxies
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Galaxy groups consist of a few tens of galaxies bound in a common gravitational potential and contain a significant fraction of the overall universal baryon budget. Therefore, they are key to our understanding of how the bulk of matter in the Universe accretes and forms hierarchical structures and how different sources of feedback affect their gravitational collapse. However, despite their crucial role in cosmic structure formation and evolution, galaxy groups have received less attention compared to massive clusters. This is perhaps in part due to their rarity in being observed and properly characterized. With the advent of eROSITA, many thousands of galaxy groups will be detected by X-ray, complementing optical and SZ coverage. In this Special Issue we collected and organized the latest developments in our understanding of these systems and present future prospects from both observational and theoretical points of view.
fossil galaxy groups --- galaxy clusters --- galaxy groups --- X-ray and optical observations --- hydrodynamical simulations --- intragroup medium/plasma --- active galactic nuclei --- black holes --- elliptical galaxies --- active nuclei --- X-ray observations --- hydrodynamical and cosmological simulations --- galaxies:abundances --- galaxies:clusters:intracluster medium --- X-rays:galaxies --- galaxy surveys --- UV observations --- cosmological parameters --- n/a
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