Download or read book A Study of the Kinematics and Nuclear Structure of the Barred Spiral Galaxies NGC 1365 and NGC 1512 and of the Nuclear Jet in NGC 3309 written by Steven Jörsäter and published by . This book was released on 1984 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of the Kinematics and Nuclear Structure of Barred Spiral Galaxies NGC 1365 and 1512 and of the Nuclear Jet in NGC 3309 written by Steven Jörsäter and published by . This book was released on 1984 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structures and Dynamics of Ngc 3359 written by Veera Boonyasait and published by . This book was released on 2003 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spiral Structure in Galaxies written by Giuseppe Bertin and published by MIT Press. This book was released on 1996 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: How does it happen that billions of stars can cooperate to produce the beautiful spirals that characterize so many galaxies, including ours? This book presents a theory of spiral structure that has been developed over the past three decades under the continuous stimulus of new observational studies. The theory unfolds in a way that can be grasped by any reader with an undergraduate science background who is interested in astronomy, as well as by graduate students and scientists actively involved in astronomy or related subjects who want to see the "backbone" and the physical content of the theory. The foundations of this theoretical framework were laid in the early 1960s, following the pioneering work of B. Lindblad. C. C. Lin had already contributed significantly to the field of fluid mechanics when he turned his attention to spiral structures, and he has focused on the problem ever since. Giuseppe Bertin joined this research effort when he first visited at MIT in 1975, bringing to the project knowledge from his work on elliptical galaxies and plasma astrophysics. Together, Bertin and Lin have contributed to the exciting developments on spiral structure of the last few decades, working closely with many observers and other theorists. In this book they describe the density-wave theory with the goal of making the key concepts and astrophysical implications explicit and accessible. The essence of the solution Bertin and Lin present is that the spirals are wave rather than material phenomena and generally trace intrinsic characteristics of the individual galaxies. The book is in three parts--Physical Concepts, Observational Studies, and Dynamical Mechanisms--with most of the technical details confined to the last part.
Download or read book Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 1365 written by Per A. B. Lindblad and published by . This book was released on 1994 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Understanding the Formation and Evolution of Nuclei in Galaxies Using N body Simulations written by Markus Hartmann and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Central massive objects like supermassive black holes and stellar nuclear clusters are common in all type of galaxies. I use N-body simulations to study the formation and evolution of nuclear clusters and to investigate the influence of the dynamical evolution of disc galaxies on the structural and kinematical properties of the host galaxy. I show that the second moment of velocities determine a lower limit on the dissipative formation process, which is about 50% in the case of the nuclear cluster in the late-type spiral galaxy NGC 4244. The vertical anisotropy of nuclear clusters can be used to determine an upper limit on the formation process due to merger or accretion of star clusters, which is about 10% for the nuclear cluster in NGC 4244. This is the first time that we have strong evidence of a hybrid formation scenario for nuclear clusters. In a set of 25 galaxy simulations I study bar formation in disc galaxies. I show that bar formation lead to the increase in mass in the central region of galaxies. This mass increase raises the velocity dispersion of stars in the disc and bulge component, which explains the offset of barred galaxies in the relation between the mass of the supermassive black hole, M., and the velocity dispersion of stars in the bulge, [delta]e, the M. - [delta]e relation (Gueltekin et al. 2009). While Graham et al. (2011) argued that the orbital structure of stars within the bar could be responsible for the observed offset of barred galaxies from the M. - [delta]e relation of unbarred galaxies, I show that the effect of stellar orbits in bars on [delta]e is less than 15% compared to the increase in mass which raises [delta]e by 40%. The offset I find in the simulation is comparable to the offset using the recent sample of M. measurements of elliptical, unbarred and barred disc galaxies from Gueltekin et al. (2009).
Download or read book Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 1365 written by and published by . This book was released on 1996 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Optical and HI Study of the Interacting Galaxies NGC 1512 and 1510 written by and published by . This book was released on 1979 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Stellar Kinematics and Dynamics of Barred Galaxies I NGC 936 written by Kormendy, J. (John) and published by . This book was released on 1983 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mass and Luminosity Distributions in the Barred Spiral Galaxies NGC 1566 and NGC 1808 written by Stephen George Bransgrove and published by . This book was released on 1985 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Shearing Spiral Arms of the Barred Galaxy Ngc 1365 written by Jason C. Speights and published by . This book was released on 2008 with total page 150 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 The H I Distribution and Dynamics in Two Late type Barred Spiral Galaxies written by Daniel J. Pisano and published by . This book was released on 1997 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure of Active Galactic Nuclei written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-13 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: We are continuing our systematic investigation of the nuclear structure of nearby active galactic nuclei (AGN). Upon completion, our study will characterize hypothetical constructs such as narrow-line clouds, obscuring tori, nuclear gas disks. and central black holes with physical measurements for a complete sample of nearby AGN. The major scientific goals of our program are: (1) the morphology of the NLR; (2) the physical conditions and dynamics of individual clouds in the NLR; (3) the structure and physical conditions of the warm reflecting gas; (4) the structure of the obscuring torus; (5) the population and morphology of nuclear disks/tori in AGN; (6) the physical conditions in nuclear disks; and (7) the masses of central black holes in AGN. We will use the Hubble Space Telescope (HST) to obtain high-resolution images and spatially resolved spectra. Far-UV spectroscopy of emission and absorption in the nuclear regions using HST/FOS and the Hopkins Ultraviolet Telescope (HUT) will help establish physical conditions in the absorbing and emitting gas. By correlating the dynamics and physical conditions of the gas with the morphology revealed through our imaging program, we will be able to examine mechanisms for fueling the central engine and transporting angular momentum. The kinematics of the nuclear gas disks may enable us to measure the mass of the central black hole. Contemporaneous X-ray observations using ASCA will further constrain the ionization structure of any absorbing material. Monitoring of variability in the UV and X-ray absorption will be used to determine the location of the absorbing gas, possibly in the outflowing warm reflecting gas, or the broad-line region, or the atmosphere of the obscuring torus. Supporting ground-based observations in the optical, near-IR, imaging polarimetry, and the radio will complete our picture of the nuclear structures. With a comprehensive survey of these characteristics in a complete sample of nearby AGN, our conclus...
Download or read book The Peculiar Spiral Galaxy NGC 4258 written by Geert Dick van Albada and published by . This book was released on 1978 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary also in Dutch.
Download or read book The Distribution of Light Around the Nucleus in the Spiral Galaxies NGC 4258 and NGC 7331 written by Odd Jensen and published by . This book was released on 1960 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure and Dynamics of the Spiral Galaxy NGC 4736 written by Robert Andrew Schommer and published by . This book was released on 1977 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
