Download or read book The Nature of Emission line Profile Variability and the Structure of the Line emitting Regions in Active Galactic Nuclei written by Kirk Thomas Korista and published by . This book was released on 1990 with total page 422 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 1994 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Nature of Compact Objects in Active Galactic Nuclei written by Andrew Robinson and published by Cambridge University Press. This book was released on 1994-03-03 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: What evidence is there for and against unified schemes for active galactic nuclei (AGN)? How do the AGN populations evolve over cosmological timescales? And what can the variability of their UV and X-ray emission tell us? These are just some of the exciting issues addressed in this volume of papers collected from the 33rd Herstmonceux conference in Cambridge. AGN are among the most spectacular objects known to astronomy. Yet, despite years of intense and wide-ranging research, the debate continues - what is their fundamental source of power? Rapid progress has been made towards answering this question by a variety of large-scale, multi-wavelength monitoring campaigns and the latest generation of satellite-borne observations. This volume provides a valuable overview and timely update of the exciting and rapidly developing field of AGN research - essential reading for graduate students and researchers.
Download or read book EMISSION LINE REGIONS IN ACTIVE GALACTIC NUCLEI STRUCTURE KINEMATICS PHYSICAL CONDITIONS AND CHEMICAL ABUNDANCES SEYFERT GALAXIES written by ANURADHA PURUSHOTTAM KORATKAR and published by . This book was released on 1990 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: a high confidence level. The rapid variability of the 3C 273 BLR suggests that there might be anisotropic continuum variability.
Download or read book Reverberation Mapping of the Broad line Region in Active Galactic Nuclei written by Rutherford Appleton Laboratory. Workshop on Astronomy and Astrophysics and published by . This book was released on 1994 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Active Galactic Nuclei written by Hugh Richard Miller and published by Springer. This book was released on 1988-07-13 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume summarizes recent developments in our understanding of active galactic nuclei, including quasars, seyfert galaxies and radio galaxies. The predominant emphasis is put on observational results with information from essentially all wave bands, but important theoretical results are also presented. Among the contributions are discussions of the different types of active galaxies, the nature of the central engine, the wiggly structure of radio jets, the dynamics of the gas in jets, the study of millimeter and extreme ultraviolet regions, and a discussion of the observed continuum of the entire electromagnetic spectrum. The intended readers are professional astronomers and astrophysicists as well as graduate students in this field of research.
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 ON THE STRUCTURE AND KINEMATICS OF ACTIVE GALACTIC NUCLEI OBSERVATIONAL ASPECTS written by E. Perez Jimenez and published by . This book was released on 1987 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spectropolarimetry Variability and the Taxonomy of Active Galactic Nuclei written by Robert W. Goodrich and published by . This book was released on 1988 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Active Galactic Nuclei written by Professor R. D. Blandford and published by Springer. This book was released on 2013-12-14 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1993-03 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Steps Toward Determination of the Size and Structure of the Broad Line Region in Active Galactic Nuclei 8 An Intensive Hst Iue and Ground Based St written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-11-14 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the data and initial results from a combined HST/IUE/ground-based spectroscopic monitoring campaign on the Seyfert 1 galaxy NGC 5548 that was undertaken in order to address questions that require both higher temporal resolution and higher signal-to-noise ratios than were obtained in our previous multiwavelength monitoring of this galaxy in 1988-89. IUE spectra were obtained once every two days for a period of 74 days beginning on 14 March 1993. During the last 39 days of this campaign, spectroscopic observations were also made with the HST Faint Object Spectrograph (FOS) on a daily basis. Ground-based observations, consisting of 165 optical spectra and 77 photometric observations (both CCD imaging and aperture photometry), are reported for the period 1992 October to 1993 September, although much of the data are concentrated around the time of the satellite-based program. These data constitute a fifth year of intensive optical monitoring of this galaxy. In this contribution, we describe the acquisition and reduction of all of the satellite and ground-based data obtained in this program. We describe in detail various photometric problems with the FOS and explain how we identified and corrected for various anomalies. During the HST portion of the monitoring campaign, the 1350 A continuum flux is found to have varied by nearly a factor of two. In other wavebands, the continuum shows nearly identical behavior, except that the amplitude of variability is larger at shorter wavelengths, and the continuum light curves appear to show more short time-scale variability at shorter wavelengths. The broad emission lines also vary in flux, with amplitudes that are slightly smaller than the UV continuum variations and with a small time delay relative to the UV continuum. On the basis of simple time-series analysis of the UV and optical continuum and emission line light curves, we find (1) that the ultraviolet and optical continuum variations are virtually simultaneous, wi...
Download or read book Astrophysics Of Quasi Stellar Objects And Active Galactic Nuclei written by Joseph S. Miller and published by University Science Books. This book was released on 1985 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Based on the 1984 Santa Cruz Astrophysics Workshop"--Verso t.p.
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 787 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is devoted 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 documenta tion 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, compared to which our system of accumu lating abstracts for about six months offers the advantage of greater convenience for the user. Volume 31 contains literature published in 1982 and received before July 15, 1982; some older literature which was received late and which is not recorded in earlier volumes is also included. We acknowledge with thanks contributions to this volume by Dr. J. Bouska, Prague, who surveyed journals and publications in Czech and supplied us with abstracts in English .
Download or read book Energy Research Abstracts written by and published by . This book was released on 1988 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1988 with total page 1132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Literature 1987 Part 2 written by U. Esser and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Astronomy and Astrophysics Abstracts aims to present a comprehensive documen tation of the literature concerning all aspects of astronomy, astrophysies, and their border fields. It is devoted to the recording, summarizing, and indexing of the relevant publications throughout the world. Astronomy and Astrophysics Abstracts is prepared by a special department of the Astronomisches Rechen-Institut under the auspices of the International Astronomical Union. Volume 44 records literature published in 1987 and received before February 15, 1988. Some older documents which we received late and which are not surveyed in earlier volumes are inc1uded too. We acknowledge with thanks contributions of our colleagues all over the world. We also express our gratitude to all organiza tions, observatories, and publishers which provide us with complimentary copies of their publications. Dr. Siegfried Böhme retired from his duties as co-editor of Astronomy and Astro physics Abstracts on December 31, 1987. Since 1950 he partieipated in the biblio graphie work of the institute. He served as a reviewer for the Astronomischer Jahresbericht and became one of the editors of Astronomy and Astrophysics Ab stracts in 1969. After his retirement in 1975 he took care of, particularly, the Russian literature on a voluntary basis for 12 years. It is a pleasure to thank Siegfried Böhme for his valuable contributions. Starting with Volume 33, all the recording, correction, and data processing work was done by means of computers. The recording was done by our technical staff members Ms. Helga Ballmann, Ms. Christiane Jehn, Ms. Monika Kohl, Ms.
