Download or read book Molecular Gas and Star Formation in the Central Regions of Virgo Spiral Galaxies written by Blaise Canzian and published by . This book was released on 1990 with total page 662 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Star Formation in Galaxies written by and published by . This book was released on 1987 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mapping the Galaxy and Nearby Galaxies written by Keiichi Wada and published by Springer Science & Business Media. This book was released on 2007-12-20 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Readers with any kind of an interest in astronomy will find this work fascinating, detailing as it does the proceedings of the symposium of the same name held in Japan in 2006. The symposium focused on mapping the interstellar media and other components in galactic disks, bulges, halos, and central regions of galaxies. Thanks to recent progress in observations using radio interferometers and optical/infrared telescopes in ground and space, our knowledge on structures of our Galaxy and nearby galaxies has been growing for the last decade.
Download or read book Molecular Gas in Dwarf Galaxies written by Adam Kirby Leroy and published by . This book was released on 2006 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gas Distribution Star Formation and Giant Molecular Cloud Evolution in Nearby Spiral Galaxies written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Vision Of An Old Cluster A Untangling Coma Berenices written by Alain Mazure and published by World Scientific. This book was released on 1998-08-15 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Together with Virgo, the Coma Berenices cluster is one of the most well-studied clusters at all wavelengths and in all aspects, from the Sunyaev-Zeldovich effect to star formation in galaxies. In a way, it is the prototype of rich clusters. Recent observational results, linked to the improvement of techniques such as X-ray and UV observations, along with multi-object spectroscopy, have shown that they could change our vision of this cluster. It is thus time for observers and theoreticians to confront all these new ideas and observations on the Coma cluster.The topics in this volume include: cosmological aspects of the Coma cluster, comparison with distant clusters; substructures; matter content and distribution; Sunyaev-Zeldovich effect; dynamical modelling, cluster dynamics; environmental effects on galaxies, star formation.
Download or read book The Star Formation History of Virgo Spiral Galaxies written by Cirino Pappalardo and published by . This book was released on 2010 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the influence of ram pressure stripping on the star formation history of cluster spiral galaxies. Ram pressure stripping is the hydrodynamical interaction between the interstellar medium (ISM) of a spiral galaxy that is moving inside the potential well of a cluster, and the intracluster medium (ICM). If the dynamical pressure exerted by the ICM is larger than the restoring force due to the galactic potential, the galaxy loses gas from the outer disk. The Virgo cluster is an ideal laboratory to study environmental effects on galaxy evolution, because it is rich in spirals and dynamically young. From observations we know that the amount of atomic gas in Virgo spirals is less than that of galaxies in the field. In particular cluster spirals show truncated HI disks (Giovanelli & Haynes 1983, Cayatte et al. 1990). For those galaxies that also show a symmetrical stellar distribution, ram pressure stripping is the most probably origin of the gas-disk truncation.
Download or read book The Realm of the Nebulae written by Edwin Powell Hubble and published by Yale University Press. This book was released on 1982-01-01 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: No modern astronomer made a more profound contribution to our understanding of the cosmos than did Edwin Hubble, who first conclusively demonstrated that the universe is expanding. Basing his theory on the observation of the change in distanct galaxies, called red shift, Hubble showed that this is a Doppler effect, or alteration in the wavelength of light, resulting from the rapid motion of celestial objects away from Earth. In 1935, Hubble described his principal observations and conclusions in the Silliman lectures at Yale University. These lectures were published the following year as "The Realm of the Nebulae," which quickly became a classic work.
Download or read book Radial Gas Flows and Star Formation in Spiral Galaxies written by Tony Hao Wong and published by . This book was released on 2000 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Planets Stars and Stellar Systems written by William C Keel and published by Springer. This book was released on 2013-02-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is volume 6 of Planets, Stars and Stellar Systems, a six-volume compendium of modern astronomical research, covering subjects of key interest to the main fields of contemporary astronomy. This volume on “Extragalactic Astronomy and Cosmology” edited by William C. Keel presents accessible review chapters on Galaxy Morphology, Elliptical and Disk Galaxy Structure and Modern Scaling Laws, Star Formation in Galaxies, The Cool ISM in Galaxies, The Influence of Environment on Galaxy Evolution, Clusters of Galaxies, Active Galactic Nuclei, Large Scale Structure of the Universe, Distance Scale of the Universe, Galaxies in the Cosmological Context, Evolution of Active Galactic Nuclei, The Intergalactic Medium, and Cosmic Microwave Background. All chapters of the handbook were written by practicing professionals. They include sufficient background material and references to the current literature to allow readers to learn enough about a specialty within astronomy, astrophysics and cosmology to get started on their own practical research projects. In the spirit of the series Stars and Stellar Systems published by Chicago University Press in the 1960s and 1970s, each chapter of Planets, Stars and Stellar Systems can stand on its own as a fundamental review of its respective sub-discipline, and each volume can be used as a textbook or recommended reference work for advanced undergraduate or postgraduate courses. Advanced students and professional astronomers in their roles as both lecturers and researchers will welcome Planets, Stars and Stellar Systems as a comprehensive and pedagogical reference work on astronomy, astrophysics and cosmology.
Download or read book Molecular Gas in Virgo Cluster Spiral Galaxies written by Jeffrey D. Kenney and published by . This book was released on 1987 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Gas and Star Formation in Nearby Galaxies written by Dyas Utomo and published by . This book was released on 2017 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the local Universe, stars form within molecular clouds. Therefore, the properties of molecular clouds may determine the star formation rate. Conversely, star formation also gives feedback to the clouds where the stars reside. In this dissertation, I present the interplay between the molecular gas and star formation, through three parts below. First, I identify and characterize the properties of molecular clouds in NGC4526, resulting in the first catalog of molecular clouds in an early-type galaxy. As a population, the molecular clouds in NGC4526 are gravitationally bound and have a steeper mass distribution than that in the Milky Way. These molecular clouds are also more luminous, denser, and have a higher velocity dispersion than their counterparts in the Milky Way. These different properties may be due to a more intense interstellar radiation field than in the Galactic disk and a weaker external pressure than in the Galactic center. Second, I combine the mm-wave interferometric data from CARMA and the optical Integral Field Unit data from CALIFA to study the molecular depletion time on kilo-parsec scales of nearby galaxies. In particular, the molecular depletion time between the galactic centers and disks is compared. I find that some galactic centers have shorter depletion time than that in the disks, which means that those centers form stars more efficiently per unit molecular gas mass. This places the galactic centers as an intermediate regime between galactic disks and starburst galaxies. The central drop of depletion time is also correlated with a central increase in the stellar mass surface density, suggesting that a shorter depletion time is associated with the molecular gas compression by the stellar gravitational potential. Third, the feedback from star formation to maintain turbulence in the interstellar matter of M33 is investigated. I show that supernovae have enough energy to maintain atomic gas turbulence inside 4 kpc radius and within molecular clouds, assuming a constant value of turbulent dissipation time of 9.8 Myrs. In the outer parts, the energy from the differential rotation of galaxy is large enough to maintain atomic gas turbulence through the magneto-rotational instability (MRI). I conclude that the sum of supernovae and MRI energy maintains turbulence at all radii where atomic hydrogen is detected in M33.
Download or read book The Evolution of Galaxies and Their Environment written by David J. Hollenbach and published by . This book was released on 1993 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Distribution of Mass Within Spiral Galaxies written by Thomas Per Krister Martinsson and published by . This book was released on 2011 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Galaxies Through Cosmic Time written by Amber Bauermeister and published by . This book was released on 2012 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past decade, molecular gas observations have begun probing the high redshift universe in a systematic way using increasingly powerful millimeter instruments. This work has significantly advanced our understanding of the history of gas consumption by star formation in galaxies, revealing the high redshift universe to be similar in many ways to what we know locally. Specifically, molecular gas studies suggest that at both high and low redshift, the molecular gas reservoir in galaxies is insufficient to support on-going star formation. This is the molecular gas depletion problem, and motivates the research presented in this dissertation. I first investigate the molecular gas depletion problem on cosmic scales. Using the observed cosmic densities of the star formation rate, atomic gas and molecular gas, combined with measurements of the molecular gas depletion time in local galaxies, I derive the history of gas consumption by star formation from z = 0 to z ~ 4. I show that models in which the molecular gas is not replenished, or is only replenished by atomic gas, are not consistent with observational constraints. I find that star formation on cosmic timescales must be fueled by intergalactic ionized gas at an average rate that roughly traces the star formation rate density of the universe. Further, I predict the volume averaged density of molecular gas to increase by a factor of 1.5 - 10 to z ~ 1.5 over the currently measured value, which implies that galaxies at high redshift must, on average, be more molecular gas-rich than they are at the present epoch, consistent with observations. Next I focus on the observational constraints on the molecular gas content of galaxies from z ~ 1 - 2 to today. Recent observations suggest z ~ 1 - 2 galaxies harbor molecular gas reservoirs an order of magnitude larger than their local counterparts, implying significant evolution of the molecular gas content of galaxies over the past 8 billion years. However, this period of time has been relatively un-observed in molecular gas. To fill in this observational gap, I carry out the Evolution of molecular Gas in Normal Galaxies (EGNoG) survey, a study of molecular gas in 31 star-forming galaxies from z = 0.05 to z = 0.5. With observations of the CO(1-0) and CO(3-2) rotational lines using the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the EGNoG survey accomplishes two goals: tracing the evolution of the molecular gas content of galaxies at intermediate redshifts and constraining the excitation of the molecular gas in these galaxies. With 24 detections out of 31 observed galaxies, I calculate an average molecular gas fraction of 7 - 20% at z ~ 0.05 - 0.5, which is in line with observations at high and low redshift and agrees well with the evolution predicted by a simple empirical prescription for gas consumption by star formation in galaxies from z ~ 1 - 2 to today. The EGNoG observations of four galaxies at z = 0.3 (the gas excitation subsample) yield robust detections of both lines in three galaxies (and an upper limit on the fourth). I find an average line ratio, r31 = L'(CO(3-2)) / L'(CO(1-0)), of 0.46 ± 0.07 (with systematic errors less than 40%), which implies sub-thermal excitation of the CO(3-2) line. As the EGNoG galaxies are representative of the main sequence of star-forming galaxies, I extend this result to include main sequence galaxies at high redshift. To support the observations carried out at CARMA as part of the EGNoG survey, I give two appendices. The first details the data reduction and flux measurement for the EGNoG survey, including a description of the use of polarized calibrators to calibrate data from single, linearly polarized feeds. In the second appendix, I describe the absolute flux calibration of CARMA data and the automated monitoring system I helped put in place in order to maintain a historical record of the flux of common calibrators. Finally, I return to the gas depletion problem in the local universe. I carry out a pilot study of atomic (HI) gas in groups of galaxies in order to investigate the role of tidal interactions in transporting atomic gas from the outskirts of galaxy disks to the central regions so that it may replenish the molecular gas and fuel ongoing star formation. I image three groups of galaxies in the 21 cm line of HI with the Allen Telescope Array (ATA), detecting many galaxies not previously observed in HI as well as four previously undetected clouds of HI between galaxies that account for up to 3% of the HI reservoir of the groups. To investigate the potential role of this gas in the ongoing star formation in the group, I compare the mass of the detected HI gas in and between galaxies in the group to the estimated star formation rates of the group members.
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 The Interstellar Medium in External Galaxies written by David J. Hollenbach and published by . This book was released on 1990 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt:
