Download or read book A Study of the Structure and Kinematics of the Narrow line Region in Seyfert Galaxies written by Sylvain Veilleux and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 1989 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Kinematics of the Narrow line Regions in the Seyfert Galaxies NGC 4151 and NGC 1068 written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present a study of high-resolution long-slit spectra of the Narrow-Line Regions (NLRs) of NGC 4151 (a Seyfert 1 galaxy) and NGC 1068 (a Seyfert 2 galaxy) obtained with the Space Telescope Imaging Spectrograph (STIS) aboard the Hubble Space Telescope (HST). The spectra were retrieved from the Multimission Archive at Space Telescope (MAST) and were obtained from five and seven orbits of HST time resulting in five and seven parallel slit configurations at position angles of 52 degrees and 38 degrees for NGC 4151 and NGC 1068 respectively. The spectra have a spatial resolution of 0.2 arcsecond across and 0.1 arcsecond along each slit. Observations of [O III] emission from the NLRs were made using the medium resolution G430M grating aboard HST. The spectral resolving power of the grating, R~ 9000, resulted in the detection of multiple kinematic components of the [O III] emission line gas along each slit. Radial velocities of the components were measured using a Gaussian fitting procedure. Biconical outflow models were generated to match the data and for comparison to previous models done with lower dispersion observations. The general trend is an increase in radial velocity roughly proportional to distance from the nucleus, followed by a linear decrease after roughly 100 pc. This is similar to that seen in other Seyfert galaxies, indicating common acceleration and deceleration mechanisms. The full-width at half-maximum (FWHM) of the emission lines reaches a maximum of 1000 km/s near the nucleus, and generally decreases with increasing distance to about 100 km/s in the extended narrow-line region (ENLR), starting at about 400 pc from the nucleus. In addition to the bright emission knots, which generally fit our model, there are faint high velocity clouds that do not fit the biconical outflow pattern of our kinematic model. A comparison of our observations with high-resolution radio maps shows that the kinematics of the faint NLR clouds may be affected by the radio lobes that comprise the inner jet. However, the bright NLR clouds show a smooth transition across the radio knots in radial velocity and velocity dispersion plots and remain essentially undisturbed in their vicinity, indicating that the radio jet is not the principal driving force on the outflowing NLR clouds. A dynamical model was developed for NGC 1068; it includes forces of radiation pressure, gravity, and drag due an ambient medium, simultaneously acting on the NLR clouds. The velocity profile from this model was too steep to fit the data, which show a more slowly increasing velocity profile. Gravity alone was not able to slow down the clouds but with the drag forces included, the clouds could slow down, reaching systemic velocities at distances that depend on the column densities of the NLR gas and density of the intercloud medium. A biconical model using the geometric parameters from our kinematic fit, and the velocity law from the dynamic fit, was used to match the data. The resulting dynamic model represented a poor fit to the data, indicating the need for additional dynamical considerations.
Download or read book An Observational Study of the Narrow line Region of Intermediate Seyfert Galaxies written by Ross David Cohen and published by . This book was released on 1981 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Narrow line Regions of Jet dominated Seyfert Galaxies written by David John Vikas Rosario and published by . This book was released on 2007 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quasars at All Cosmic Epochs written by and published by . This book was released on 2018 with total page 0 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 Examining the Kinematics of Narrow line Region Gas in Active Galaxies Using HST written by José R. Ruiz and published by . This book was released on 2003 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Broad Line Variations and Kinematics of Seyfert Galaxies written by Edward I. Rosenblatt and published by . This book was released on 1989 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atomic Transition Probabilities written by W. L. Wiese and published by . This book was released on 1966 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Emission Line Regions Kinematics in Selected Seyfert Galaxies written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Astrophysics Of Gas Nebulae and Active Galactic Nuclei written by Donald E. Osterbrock and published by University Science Books. This book was released on 2006 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thoroughly revised and expanded throughout, the new edition is a graduate-level text and reference book on gaseous nebulae, nova and supernova remnants. Much of the new data and new images are from the Hubble Space Telescope with two wholly new chapters being added along with other new features. The previous edition which was tried and tested for thirty years has now been succeeded by a revised, updated, larger edition, which will be valuable to anyone seriously interested in astrophysics.
Download or read book Motions in the Narrow Line Regions of Seyfert Galaxies written by William Stuart Carter and published by . This book was released on 1993 with total page 282 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 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
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 Seyfert Galaxy Narrow line Regions written by Jan Mojmir Vrtilek and published by . This book was released on 1983 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Possible Models for Balmer Emission Line Regions in Seyfert Galaxies written by William Merritt Adams and published by . This book was released on 1973 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study is directed toward two unexplained phenomena exhibited by the Balmer emission lines in Seyfert galaxies; their unique profile structure, and their anomalous intensity ratios. The study of the line profiles consists of an examination of three proposed mechanisms for explaining the broad wings found on the Balmer lines in several of these objects. The models considered are: (1) a uniform medium in which self-absorption of allowed lines increases their escape path length, thus increasing the probability of their being electron scattered so as to account for the wings; (2) the line wings are formed in a separate region with high velocity dispersion; and (3) the lines with wings are formed in a separate region with high velocity dispersion; optical depth is greater, thus creating the wings by electron scattering. It is concluded that the evidence favors the third possibility. (Modified author abstract).
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.
