Download or read book The Central Structure of Radio Quasars written by Alicia Yinema Kate Nungarai Oshlack and published by . This book was released on 2002 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Small Scale Structure of Radio Galaxies and Quasars at 3 8 CM written by M. H. Cohen and published by . This book was released on 1971 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fringes were observed from 31 compact radio sources, including 8 known or suspected galaxies and 20 known or suspected quasars, by using the Goldstack interferometer at Lambda = 3.8 cm (d/Lambda = one hundred million). Fringe visibility curves were obtained for 9 sources showing structure on a scale of 0.001 sec of arc and simple models are fit to the data. Results for 3C 273 and 3C 279 are compared with data taken by Knight et al. (1971) at an earlier epoch. The apparent changes in brightness distribution of 3C 273 and 3C 279 are difficult to explain in terms of a super-light expansion. (Author).
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 An Introduction to Radio Astronomy written by Bernard F. Burke and published by Cambridge University Press. This book was released on 2019-08-22 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radio astronomy is an active and rapidly expanding field due to advances in computing techniques, with several important new instruments on the horizon. This text provides a thorough introduction to radio astronomy and its contribution to our understanding of the universe, bridging the gap between basic introductions and research-level treatments. It begins by covering the fundamentals physics of radio techniques, before moving on to single-dish telescopes and aperture synthesis arrays. Fully updated and extensively rewritten, the fourth edition places greater emphasis on techniques, with detailed discussion of interferometry in particular, and comprehensive coverage of digital techniques in the appendices. The science sections are fully revised, with new author Peter N. Wilkinson bringing added expertise to the sections on pulsars, quasars and active galaxies. Spanning the entirety of radio astronomy, this is an engaging introduction for students and researchers approaching radio astronomy for the first time.
Download or read book Quasars Agns and Related Research Across 2000 written by Lodewijk Woltjer and published by Springer Science & Business Media. This book was released on 2001-07-17 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proceedings of the international conference held in honor or Lodewijk Woltjer, focus on the physics, origin and space distribution of AGNs and quasars and their relationship to the environment, a very wide subject which has attracted much of Lodewijk Wolter's research interest. A number of lectures were also dedicated to reviewing the recent observational advances and those that may be attained by the introduction of new and powerful astronomical instrumentation both from the ground and from space, in recognition of the central role played by L. Woltjer in the promotion of the ESO VLT and of his involvement in shaping ESA's space programme Horizon 2000+.
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 Astronomy and Astrophysics Abstracts written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-12-14 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: Astronomy and Astrophysics Abstracts has appeared in semi-annual volumes since 1969 and it has already become one of the fundamental publications in the fields of astronomy, astrophysics and neighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. ... The abstracts are classified under more than hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world." Space Science Reviews #1 "Dividing the whole field plus related subjects into 108 categories, each work is numbered and most are accompanied by brief abstracts. Fairly comprehensive cross-referencing links relevant papers to more than one category, and exhaustive author and subject indices are to be found at the back, making the catalogues easy to use. The series appears to be so complete in its coverage and always less than a year out of date that I shall certainly have to make a little more space on those shelves for future volumes." The Observatory Magazine #1
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 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fifty Years of Quasars written by Mauro D'Onofrio and published by Springer Science & Business Media. This book was released on 2012-06-30 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: Formatted as a series of interviews with noted researchers in the field, this book reviews the history of quasar research and describes how advances in instrumentation and computation have aided quasar astronomy and changed our basic understanding of quasars.
Download or read book Extragalactic Radio Sources written by D.S. Heeschen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: IAU Symposium 97, Extragalactic Radio Sources, was held at Albuquerque, New Mexico August 3-7, 1981. It was co-sponsored by IAU Commissions 28, 40, 47 and 48 and by URSI Commission J. Financial and organizational support were provided by the National Radio Astronomy Observatory, the University of New Mexico, and the National Science Foundation. A wide variety of interesting objects and phenomena can be covered under the heading "Extragalactic Radio Sources", and a diverse set of topics was in fact discussed at the symposium. Radio galaxies, quasars, Seyfert galaxies and BL Lacertids received the most attention, but normal galaxies, the galactic center, and even SS433 were also discussed. While the unifying theme of the symposium was radio emission, studies at all wavelengths--X-ray, UV, optical, IR, and radio--were included. In general, the emphasis was on individual objects and the physical processes associated with them, but there were also papers on statistical studies and cosmology. The symposium was attended by 209 scientists from 18 countries.
Download or read book VLBI and Compact Radio Sources written by Roberto Fanti and published by Springer Science & Business Media. This book was released on 1984-05-31 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: I.A.U. symposium No. 110 on VLBI and Compact Radio Sources was held in Bologna, Italy from June 27 to July 1, 1983. 166 participants from 19 countries were registered and 106 invited and contributed papers were registered. The scientific presentations and discussion concentrated on VLBI observation and interpretation of galactic and extragalactic radio sour ces, including topics as diverse as quasars and galactic nuclei, inter stellar masers, pulsars, and astrometry. Geodetic applications and tech nical development were treated only briefly, as these topics have been the subject of other recent international symposia. Since the first VLBI observations in 1967, sensitivity, resolution, and image quality have improved dramatically. Radio maps shown at the symposium were of comparable quality to conventional synthesis maps be ing made at the time of the first VLBI experiments 15 years ago, but with a resolution more than a factor of 1000 better. We wanted to accommodate the large number of contributed papers in this rapidly developing field, but there was inadequate time for normal oral presentations and discussion. We therefore asked that all contrib uted papers be put on display for at least 24 hours prior to a brief oral summary. A question and discussion period followed groups of oral pres entations on the same or similar topic. In this way the opportunity for interactive discussion, not available in conventional poster displays, was preserved.
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 Jets in Extragalactic Radio Sources written by Klaus Meisenheimer and published by . This book was released on 1993 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: The existence of jets emanating from the central sources of radio galaxies and quasars was perhaps the most important discovery for our understanding of the nature of active galactic nuclei. These proceedings present reviews and research papers on extragalactic radio sources. The book begins witha discussion of the phenomenology and models of radio sources. The main partis devoted to detailed studies of jets by VLBI, to the information obtained about the structure of the central source as deduced from variability studies, to production, confinement and velocity of jets as well as to numerical simulations of the jet phenomenon. Reviews of the two best studied jets - those in the radio galaxy M87 and the quasar 3C273 - illustrate our current observational picture of extragalactic radio jets in all accessible wavelength ranges. A section on the influence of the environment on radio galaxies concludes the book. This topical volume addresses researchers and graduate students in astrophysics.
Download or read book National Optical Astronomy Observatories Newsletter written by and published by . This book was released on 2001 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1974 Part 1 written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is de voted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documentation of literature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original literature and publication of the abstracts will not exceed eight months. This time interval is near to that achieved by monthly abstracting journals, com pared to which our system of accumulating abstracts for about six months offers the advantage of greater convenience for the user. Volume II contains literature published in 1974 and received before August IS, 1974; some older literature which was received late and which is not recorded in earlier volumes is also included. Begin ning with this volume some minor changes of our classification scheme have been made. We acknowledge with thanks contributions to this volume by Dr. J. BouSka, who surveyed journals and publications in the Czech language and supplied us with abstracts in English, and by the Common wealth Scientific and Industrial Research Organization (C.S.I.R.O.), Sydney, for providing titles and abstracts of papers on radio astronomy.
Download or read book Radio Galaxies written by A. G. Pacholczyk and published by Elsevier. This book was released on 2014-06-20 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radio Galaxies: Radiation Transfer, Dynamics, Stability and Evolution of a Synchrotron Plasmon deals with the physics of a region in space containing magnetic field and thermal and relativistic particles (a plasmon). The synchrotron emission and absorption of this region are discussed, along with the properties of its spectrum; its linear and circular polarization; transfer of radiation through such a region; its dynamics and expansion; and interaction with external medium. Comprised of eight chapters, this volume explores the stability, turbulence, and acceleration of particles in a synchrotron plasmon as well as its application to the physics of radio galaxies. The discussion begins with a description of extragalactic radio sources and their properties, followed by an analysis of the emission and absorption of synchrotron radiation. Subsequent chapters focus on the transfer of polarized radiation in a magnetoactive plasma; hydromagnetics and hydromagnetic stability; confinement and structure of extended radio sources; and radio-tail galaxies. The book also considers compact radio sources before concluding with an evaluation of radio source theories. This monograph is addressed primarily to radio astronomers and graduate students working on the interpretation of observational data.
