Download or read book Distant Obscured Quasars written by Alejo Martínez-Sansigre and published by . This book was released on 2006 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Associations Between Galaxies and Distant Quasars written by Lucyna Kedziora-Chudczer and published by . This book was released on 1992 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Supermassive Black Holes in the Distant Universe written by A.J. Barger and published by Springer Science & Business Media. This book was released on 2013-11-09 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quasars, and the menagerie of other galaxies with "unusual nuclei", now collectively known as Active Galactic Nuclei or AGN, have, in one form or another, sparked the interest of astronomers for over 60 years. The only known mechanism that can explain the staggering amounts of energy emitted by the innermost regions of these systems is gravitational energy release by matter falling towards a supermassive black hole --- a black hole whose mass is millions to billions of times the mass of our Sun. AGN emit radiation at all wavelengths. X-rays originating at a distance of a few times the event horizon of the black hole are the emissions closest to the black hole that we can detect; thus, X-rays directly reveal the presence of active supermassive black holes. Oftentimes, however, the supermassive black holes that lie at the centers of AGN are cocooned in gas and dust that absorb the emitted low energy X-rays and the optical and ultraviolet light, hiding the black hole from view at these wavelengths. Until recently, this low-energy absorption presented a major obstacle in observational efforts to map the accretion history of the universe. In 1999 and 2000, the launches of the Chandra and XMM-Newton X-ray Observatories finally broke the impasse. The impact of these observatories on X-ray astronomy is similar to the impact that the Hubble Space Telescope had on optical astronomy. The astounding new data from these observatories have enabled astronomers to make enormous advances in their understanding of when accretion occurs.
Download or read book Quasars Pulsars and Black Holes written by Frederic Golden and published by . This book was released on 1977-04 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Nature of Dust Obscured Quasars written by Eilat Glikman and published by . This book was released on 2006 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quasars written by Franz Daniel Kahn and published by Manchester University Press. This book was released on 1967 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Quasars Pulsars Black Holes and HEAO s written by and published by . This book was released on 1974 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Accretion Power in Astrophysics written by Juhan Frank and published by Cambridge University Press. This book was released on 2002-01-17 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accretion Power in Astrophysics examines accretion as a source of energy in both binary star systems containing compact objects, and in active galactic nuclei. Assuming a basic knowledge of physics, the authors describe the physical processes at work in accretion discs and other accretion flows. The first three chapters explain why accretion is a source of energy, and then present the gas dynamics and plasma concepts necessary for astrophysical applications. The next three chapters then develop accretion in stellar systems, including accretion onto compact objects. Further chapters give extensive treatment of accretion in active galactic nuclei, and describe thick accretion discs. A new chapter discusses recently discovered accretion flow solutions. The third edition is greatly expanded and thoroughly updated. New material includes a detailed treatment of disc instabilities, irradiated discs, disc warping, and general accretion flows. The treatment is suitable for advanced undergraduates, graduate students and researchers.
Download or read book An Introduction to Active Galactic Nuclei written by Bradley M. Peterson and published by Cambridge University Press. This book was released on 1997-02-13 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: How can we test if a supermassive black hole lies at the heart of every active galactic nucleus? What are LINERS, BL Lacs, N galaxies, broad-line radio galaxies and radio-quiet quasars and how do they compare? This timely textbook answers these questions in a clear, comprehensive and self-contained introduction to active galactic nuclei - for graduate students in astronomy and physics. The study of AGN is one of the most dynamic areas of contemporary astronomy, involving one fifth of all research astronomers. This textbook provides a systematic review of the observed properties of AGN across the entire electromagnetic spectrum, examines the underlying physics, and shows how the brightest AGN, quasars, can be used to probe the farthest reaches of the Universe. This book serves as both an entry point to the research literature and as a valuable reference for researchers in the field.
Download or read book Origin of Regularities in the Redshift Distributions of Distant Galaxies and Quasars written by Leonid M. Ozernoy and published by . This book was released on 1991 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High redshift Universe written by Gregory Zeimann and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present the discovery of only the second radio-selected, z ~ 6 quasar. We identified the z=5.95 quasar by matching the optical detections of the deep Sloan Digital Sky Survey (SDSS) Stripe 82 with their radio counterparts in the Stripe82 VLA Survey. The discovered quasar is optically-faint, z = 22.3 and M1450 ~ -24.5, but radio-bright, with a flux density of f[subscript 1.4GHz, peak] = 0.31mJy and a radio-loudness of R ~ 1100 (where R = f[subscript 5GHz]/f2500). The i - z color of the discovered quasar places it outside the color selection criteria for existing optical surveys. We also report the discovery of an IR-selected galaxy cluster in the IRAC Distant Cluster Survey (IDCS). New data from the Hubble Space Telescope spectroscopically confirm the galaxy cluster at z = 1.89 with robust spectroscopic redshifts for seven members. The cluster exhibits a red sequence with a scatter and color indicative of a formation redshift z[subscript f]>~ 3.5. The stellar age of the early-type galaxy population is approximately consistent with those of clusters at lower redshift (1 z 1.5) suggesting that clusters at these redshifts are experiencing ongoing or increasing star formation. Finally, we present near-IR spectroscopy for 18 galaxy clusters at 1.0
Download or read book Cosmic Evolution written by Eric J. Chaisson and published by Harvard University Press. This book was released on 2001-02-16 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chaisson addresses some of the most basic issues we can contemplate: the origin of matter and the origin of life, and the ways matter, life, and radiation interact and change with time. He designs for us an expansive yet intricate model depicting the origin and evolution of all material structures.
Download or read book Quasar Hosts written by David L. Clements and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Physics and Evolution of Active Galactic Nuclei written by Hagai Netzer and published by Cambridge University Press. This book was released on 2013-09-16 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive introduction to the theory underpinning our study of active galactic nuclei and the ways we observe them.
Download or read book Quasars and Pulsars written by Dewey B. Larson and published by . This book was released on 1971 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book H and H Lines in Low and High Redshift Type 2 obscured Quasars written by Ning Jin and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
