Download or read book Stellar Disk Evolution and Gaseous Disk Turbulence of Dwarf Irregular Galaxies written by Hong-Xin Zhang and published by Springer. This book was released on 2016-08-27 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the stellar disk evolution and gas disk turbulence of the most numerous galaxies in the local Universe – the dwarf galaxies. The “outside-in” disk shrinking mode was established for a relatively large sample of dwarf galaxies for the first time, and this is in contrast to the “inside-out” disk growth mode found for spiral galaxies. Double exponential brightness profiles also correspond to double exponential stellar mass profiles for dwarf galaxies, which is again different from most spiral galaxies. The cool gas distribution in dwarf galaxies was probed with the spatial power spectra of hydrogen iodide (HI) gas emission, and provided indirect evidence that inner disks of dwarf galaxies have proportionally more cool gas than outer disks. The finding that no correlation exists between gas power spectral indices and star formation gave important constraints on the relation between turbulence and star formation in dwarf galaxies.
Download or read book Lessons from the Local Group written by Kenneth Freeman and published by Springer. This book was released on 2014-11-13 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our understanding of galaxy formation comes mostly from two sources: sensitive observations at high angular resolution of the high-redshift Universe, where galaxies are observed to be forming, and detailed observations of individual stars and clouds in the Local Group, where telltale remnants from its formative time remain and similar processes operate at a low level today. The current conference focusses on key aspects of the Local Group, composed of the Milky Way, Andromeda and Triangulum Spiral Galaxies, the Large and Small Magellanic Cloud galaxies, numerous dwarf and irregular galaxies, and intergalactic gas. Topics include the halo and thick disk of the Milky Way with its first stars and stellar streams; the Milky Way bar, bulge and outer edge; interstellar dust and turbulence; star formation processes and stellar scattering in spiral arms; views through the infrared Eyes of the Spitzer Space Telescope; globular clusters; the Local Gould Belt; stellar metallicities and elemental abundances; the environment and black hole in the Milky Way nucleus; orbits of the Magellanic Clouds and galaxy dwarfs; interstellar dust and turbulence; the outer disks and halos of the Andromeda and Triangulum galaxies; ripples from a collision in Andromeda; and arcs of carbon stars in the Triangulum and intergalactic clouds. This volume also discusses surveys of planetary nebulae, galaxy morphology at low and high redshift, cosmic evolution of star and galaxy formation and gas accretion, Lyman alpha emitting galaxies, ultra-low surface brightness imaging, and more. Readers are given a clear and comprehensive view of this wide range of topics written by specialists in each field. This is the proceedings of an International Conference at the Seychelles archipelago in May 2014, on the occasion of the 60th birthday of David Block and the millionth (base two) birthday of Bruce Elmegreen.
Download or read book Island Universes written by R. S. de Jong and published by Springer Science & Business Media. This book was released on 2007-05-24 with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains an up-to-date review of the structure and evolution of disk galaxies from both the observational and theoretical point of view. It is the proceedings of the "Island Universes" conference held at the island of Terschelling in July 2005. It brings together a broad range of aspects of disk galaxies: structure and dynamics, the latest multi-wavelength surveys, low- and high redshift observations, theory and observations.
Download or read book The Evolution of Galaxies written by Marc Sauvage and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 563 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies have a history. This has become clear from recent sky surveys which have shown that distant galaxies, formed early in the life of the Universe, differ from the nearby ones. New observational windows at ultraviolet, infrared and millimetric wavelengths (provided by ROSAT, IRAM, IUE, IRAS, ISO) have revealed that galaxies contain a wealth of components: very hot gas, atomic hydrogen, molecules, dust, dark matter ... A significant advance is expected due to new instruments (VLT, FIRST, XMM) which will allow one to explore the most distant Universe. Three Euroconferences have been planned to punctuate this new epoch in galactic research, bringing together specialists in various fields of Astronomy.
Download or read book Physics of the Gaseous and Stellar Disks of the Galaxy written by Ivan R. King and published by . This book was released on 1994 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Galaxy Formation and Evolution written by Andrea Cimatti and published by . This book was released on 2019-10-31 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive examination of nearly fourteen billion years of galaxy formation and evolution, from primordial gas to present-day galaxies.
Download or read book Galaxy Disks and Disk Galaxies written by José G. Funes (S. J) and published by . This book was released on 2001 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation Proceedings of a meeting sponsored by the Vatican Observatory and held at Pontifical Gregorian U., Rome, in June 2000. The conference included some 230 participants from 30 countries and covered topics related to the structure, formation, and evolution of galaxies with disks. Topics include the stellar and gaseous disk of the Milky Way; the global characteristics of galaxy disks; their structure, morphology, and dynamics; the gaseous components, star formation, and chemical evolution; the interactions, accretions, mergers, and starbursts; the dark and luminous matter; the establishment of the scaling laws; and the formation and evolution of disk galaxies from theoretical and observational points of view. Annotation c. Book News, Inc., Portland, OR (booknews.com)
Download or read book Dwarf Galaxies Keys to Galaxy Formation and Evolution written by Polychronis Papaderos and published by Springer Science & Business Media. This book was released on 2012-04-23 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dwarf galaxy research constitutes an extremely vibrant field of astrophysical research, with many long-standing questions still unsettled and new ones constantly arising. The intriguing diversity of the dwarf galaxy population, observed with advanced ground-based and space-borne observatories over a wide spectral window providing an unprecedented level of detail, poses new challenges for both observers and theoreticians. The aim of this symposium was to bring together these two groups to exchange ideas and new results on the many evolutionary aspects of and open issues concerning dwarf galaxies. The main topics addressed include: the birth of dwarf galaxies: theoretical concepts and observable relics across wavelengths and time, the morphological, structural and chemical evolution of dwarf galaxies, possible evolutionary connections between early-type and late-type dwarfs, the star formation history of dwarf galaxies and its dependence on intrinsic and environmental properties, the origin and implications of starburst activity in dwarf galaxies, the fate of dwarfish systems born out of tidally ejected matter in galaxy collisions.
Download or read book Dynamical Evolution of Galaxies written by Xiaolei Zhang and published by Walter de Gruyter GmbH & Co KG. This book was released on 2017-12-04 with total page 337 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research monograph presents a new dynamical framework for the study of secular morphological evolution of galaxies along the Hubble sequence. Classical approaches based on Boltzmann’s kinetic equation, as well as on its moment-equation descendants the Euler and Navier-Stokes fluid equations, are inadequate for treating the maintenance and long-term evolution of systems containing self-organized structures such as galactic density-wave modes. A global and synthetic approach, incorporating correlated fluctuations of the constituent particles during a nonequilibrium phase transition, is adopted to supplement the continuum treatment. The cutting-edge research combining analytical, N-body simulational, and observational aspects, as well as the fundamental-physics connections it provides, make this work a valuable reference for researchers and graduate students in astronomy, astrophysics, cosmology, many-body physics, complexity theory, and other related fields. Contents Dynamical Drivers of Galaxy Evolution N-Body Simulations of Galaxy Evolution Astrophysical Implications of the Dynamical Theory Putting It All Together Concluding Remarks Appendix: Relation to Kinetics and Fluid Mechanics
Download or read book Structural Properties of Clumpy Galaxies and Spheroids at High Redshift written by Anita Zanella and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis explores the still unanswered question of how distant galaxies evolve through cosmic time: on one side it focuses on star-forming clumpy galaxies, on the other it investigates the size evolution of passive compact ones. Despite star forming clumps have been observed in high-redshift irregular galaxies since a while, their nature and fate are still highly debated. Violent gravitational disk instability in gas-rich, turbulent galaxies has been proposed as the main cause for in-situ clumps formation, although a fraction of them might have an ex-situ origin. Furthermore, clumps contribution to galaxy evolution is highly debated: it is not clear yet if they are long-lived or if stellar feedback rapidly disrupts them. From both the in-depth study of an extremely young clump that we discovered in the disk of a galaxy at redshift z ~ 2, and the analysis of a full statistical sample, I concluded that at least some clumps form in-situ due to violent disk instability and that they typically live ~ 500 Myr. This supports numerical simulations indicating that clumps are longlived and could play an important role in bulge growth. This might stabilize the disk, quench star formation and have therefore a link with the formation of the compact and passive galaxies that have been observed at high redshift. They have significant smaller sizes, at fixed stellar mass, than local counterparts. This discovery has ignited an important debate concerning the possible mechanisms that could inflate the galaxy sizes without altering much their mass. I analyzed a sample of 32 galaxies and I concluded that multiple minor mergers could be the main drivers of their observed time evolution.
Download or read book Dynamical Evolution of Disk Galaxies written by Frank Hohl and published by . This book was released on 1970 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computer model for isolated disks of stars is presented and is used to study the self-consistent motion of large numbers of point masses as they move in the plane of the galactic disk. The Control Data 6600 computer system at the Langley Research Center was used to integrate the equations of motion for each star for systems containing from 50,000 to 200,000 stars. Any initially cold balanced disk was found to be violently unstable. A sufficient amount of velocity dispersion will stabilize all small-scale disturbances. However, most disks investigated were found to be unstable against slowly growing long-wavelength modes, and after about two rotations the disks tended to assume a bar-shaped structure. It was also found that the final mass distribution for most disks could be closely approximated by an exponential variation irrespective of the initial mass distribution. To study the development of spiral structure, the model was modified to include a fixed central force similar to that in the Schmidt model of the Galaxy. The mass of the stars in the disk was taken to be from 5 to 50 percent of the total mass of the Galaxy. The evolution of a number of initial distributions of stars was investigated. The results of the calculation gave a velocity dispersion for the disk stars which was about 50 percent larger than the value of about 30 km/sec found from observation of stars in the solar neighborhood. For some of the disks investigated, a pronounced spiral structure remained even after 8.5 rotations.
Download or read book Physics Briefs written by and published by . This book was released on 1993 with total page 1058 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Star forming Dwarf Galaxies and Related Objects written by D. Kunth and published by Atlantica Séguier Frontières. This book was released on 1985 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Galaxy Disk in Cosmological Context IAU S254 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2009-04-16 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: The paradigm of a dark energy- and dark matter-dominated Universe, with the hierarchical merger scenario for the formation of galaxies, has scored impressive successes in matching the observed Universe. However, the theory fails to explain the difficulty in generating ordinary disk galaxies such as the Milky Way, suggesting that some important physics must be missing in current models. IAU Symposium 254 was organized to address this question, gathering researchers from an unusually broad range of fields, from cosmology to interstellar matter, and the formation and evolution of stars. High-class reviews, lectures and posters combine to define the frontiers in the field and point the way to new avenues of research. This volume presents a unique set of succinct overviews illuminating the full range of topics in this very active field. It also honors Danish astrophysicist Bengt Strömgren (1908-1987), who laid much of the foundation for this entire field.
Download or read book The Evolution of Galaxies written by José M. Vilchez and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Galaxies have a history. This has become clear from recent sky surveys showing that distant galaxies, formed early in the life of the Universe, differ from the nearby ones. This book contains the proceedings of a 2000 conference addressing observational clues in this area.
Download or read book Introduction to Galaxy Formation and Evolution written by Andrea Cimatti and published by Cambridge University Press. This book was released on 2019-10-17 with total page 587 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive examination of nearly fourteen billion years of galaxy formation and evolution, from primordial gas to present-day galaxies.
Download or read book The Stellar Content and Star Formation Rates of Dwarf Irregular Galaxies written by Jacqueline Michelle Dunn and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The star formation histories and evolution of 70 dwarf irregular galaxies that reside in differing local and global environments are investigated. Local environment is defined by the local galaxy number density, where high indicates at least one neighbor within 200 kpc and low indicates no neighbors within 1 Mpc. Global environment is classified as either the field or a galaxy group / cluster. The shallow gravitational potentials of these galaxies are more susceptible to changes in morphology and dynamics by external perturbations, making dwarf irregular galaxies ideal candidates for a study on the role of environment in galaxy evolution. Absolute magnitudes, colors, central surface brightnesses, and star formation rates were compared using UBVRIJHK and Halpha photometry. With a high degree of statistical significance, galaxies in local high density environments have brighter central and effective surface brightnesses, while those in global high density environments have brighter absolute magnitudes, central and effective surface brightnesses, and higher star formation rates. However, no difference is seen among the different environments when considering star formation rates normalized by HI mass. Sersic profiles were fit to the V and R band surface brightness profiles of the galaxies. No correlation exists between structural characteristics and environment. Spectral energy distribution models were generated by varying the rate of stellar formation and amplitude to replicate periodic burst and constant star formation rate scenarios. Of the 28 galaxies for which star formation history analysis was performed, roughly half were well fit by one of the models. Periodic burst systems account for roughly half of those galaxies, with the remaining galaxies being better represented by continuously star forming systems. The star formation histories are uncorrelated with both local and global environmental classifications. Numerical simulations provide insight into the effects of differing gravitational environments, and indicate global environment having a larger influence on the physical properties of a dwarf galaxy. The star formation histories and structural properties of dwarf irregular galaxies were found to be independent of environment, indicating that cluster membership and proximity to a neighboring galaxy have no systematic long-term effects on the evolution of the objects in this study.
