Download or read book Parsec scale Structure in the Nuclei of Double lobed Radio Quasars written by David Hans Hough and published by . This book was released on 1986 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987 with total page 948 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quasars and Active Galactic Nuclei written by Marshall Harris Cohen and published by . This book was released on 1995 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1987-04 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parsec Scale Radio Jets written by J. Anton Zensus and published by Cambridge University Press. This book was released on 1990-08-16 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quasars and active galaxies are the most powerful emitters of radiation in the universe. Modern radio telescope arrays have shown that the ultimate energy source resides in the central few parsecs of the galactic nucleus, and powers the emitting regions by way of two oppositely-directed relativistic jets of energy. This volume presents the latest observations and theories of these remarkable objects. Topics discussed include superluminal motions, the physics of jets and shock fronts in jets, related optical observations, and cosmic evolution. Particular attention is given to the "unified theories," which attempt to show that many of the phenomena in powerful extragalactic objects are different aspects of a single, basic mechanism; the main difference in their appearance is a result of their different orientation with respect to the observer.
Download or read book Quasars and Active Galactic Nuclei written by Ajit K. Kembhavi and published by Cambridge University Press. This book was released on 1999-03-11 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: The latest observations and theoretical models are combined in this clear, pedagogic textbook for advanced undergraduates and graduate students.
Download or read book Quasars at All Cosmic Epochs written by Paola Marziani and published by Frontiers Media SA. This book was released on 2018-10-05 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Very Long Baseline Interferometry written by Marcello Felli and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: The quest for high resolution has preoccupied radio astronomers ever since radio waves were first detected from space fifty years ago. This venture was par ticularly stimulated by the discovery of quasars, and led to the development of interferometer techniques using baselines of transglobal dimensions. These meth ods have become known as Very Long Baseline Interferometry (VLBI). Arrays of radio telescopes situated all over the Earth (or even in space) are regularly used for researches in radio astronomy, reaching resolutions as small as a fraction of a milli arcsecond. The technique also allows the measurement of the positions of the radio telescopes to a few millimeters and so VLBI has become a major tool in geodesy and the study of the rotation of the Earth. VLBI has now passed the pioneer stage and is becoming a standard facility available to astronomers and geodesists, requiring the coordination of the operations of indpendently owned radio telescopes around the world. In Europe observatories from England, Federal Republic of Germany, France, Italy, Poland, Sweden and The Netherlands are coordinated in their VLBI activity by the European VLBI Network Consortium (EVN). The Programme Committee of the EVN allocates time to scientific projects on a routine basis three times a year. The Unites States has a similar arrangement of a network of independent radio observatories, and joint experiments using 'Global Network' are often made.
Download or read book The Two Sided Parsec Scale Structure of the Low Luminosity Active Galactic Nucleus in NGC 4278 written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Transport in Radio Galaxies and Quasars written by Philip E. Hardee and published by . This book was released on 1996 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Parsec scale properties of low power radio loud active galactic nuclei written by Marcello Giroletti and published by . This book was released on 2004* with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radio Structure in Quasars written by Pieter Dirk Barthel and published by . This book was released on 1984 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Observations and Simulations of Parsec scale Jets in Active Galactic Nuclei written by Amy Jo Mioduszewski and published by . This book was released on 1996 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Jets from Stars and Galactic Nuclei written by Wolfgang Kundt and published by Springer. This book was released on 2007-01-05 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jets are ubiquitous in the Universe, but ill-understood. Conservative books base their interpretations on focused stellar winds, ejected "bullets", black-hole central engines, and in-situ upgrading of electron energies via shocks. This volume, however, attempts a uniform interpretation of the bipolar-flow family, involving extremely relativistic pair plasma as the jet substance, and rotating magnets (possibly burning disks) as the central engines. Among the discussed sources are SS 433, YSO jets, planetary nebulae, our galactic center, and the class of extragalactic QSOs, both radio-loud and radio-quiet.
Download or read book Physics of the Parsec scale Structures in the Quasar 3C345 written by Andrew P. Lobanov and published by . This book was released on 1996 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structure and Kinematics of Quasar Broad Line Regions written by C. Martin Gaskell and published by . This book was released on 1999 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Proceedings of a March 1998 meeting, with papers in sections on general considerations and photoionization modeling, profile variation and reverberation mapping, flows, disks, narrow-line Seyfert 1 galaxies, the intermediate line region and lower-velocity gas, X-ray warm absorber and dust, and unified theories and connections with extended emission. Specific topics include spectral variability of NGC 4151 during 1990 and disk emission line issues. Lacks a subject index. The editor is associated with the University of Nebraska. Annotation c. Book News, Inc., Portland, OR (booknews.com)
Download or read book Quasars and Active Nuclei of Galaxies written by and published by . This book was released on 1978 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
