Download or read book Far infrared Emission from Rich Clusters of Galaxies written by Caroline Virginia Cox and published by . This book was released on 1995 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Clusters and Superclusters of Galaxies written by A.C. Fabian and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 373 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters and superclusters of galaxies are the largest objects in the Universe. They have been the subject of intense observational studies at a variety of wavelengths, from radio to X-ray which has provoked much theoretical debate and advanced our understanding of the recent evolution of the large-scale structure of the Universe. The current status of the subject is reviewed in this volume by active researchers who lectured at a NATO Advanced Study Institute held in Cambridge, England in July 1991. Much of the material is presented in a pedagogical manner and will appeal to scientists, astronomers and graduate students interested in extragalactic astronomy.
Download or read book Far Infrared Emission from Galaxies and Quasars written by Girish Kumar Beeharry and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling the Far infrared Emission in Spiral Galaxies written by Simone Bianchi and published by . This book was released on 1999 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book From Xrays to Far Infrared written by Ricardo Manuel Pérez Martínez and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Clusters of Galaxies are the largest gravitationally bound systems known. Discovered by Charles Messier in the XVIII century, they started to be systematically studied two hundred years later, when Abell and Zwicky undertook a series of surveys to identify concentrations of galaxies in the accessible Universe. These initial studies concluded that clusters of galaxies were formed by objects with the same visual colors and used them to establish memberships. This has been since then one of the biggest issues in this field: the accurate separation of cluster population versus projected foreground or background objects. One other issue is to establish the dynamical status of both the cluster itself and the sources within. From the latter, the former can be inferred, even by crude assumptions on the typical mass of the galaxies, since the velocity dispersion of the members and the cluster radius are linked via the Virial Theorem. However, early observations from spaceborne telescopes discovered significant extended X–ray emission from the cluster cores that was soon identified as Bremsstrahlung radiation in the di use intracluster plasma. The detection of such hot gas led to the calculation of the potential well needed to keep it bound to the system and the amount of gas required. Both estimates, from optical and X–ray data disagreed by up to (and even beyond) 70% in some cases. At the same time, the characteristics of the cluster population were studied and compared to field galaxies. It was found that cluster members favoured elliptical morphologies, larger masses and red colours, versus the dominant fraction of blue mid size spirals in the field. Moreover, the fraction of blue galaxies was found to vary along the clustercentric distance and with redshift, increasing this blue fraction directly with both. It was established that clusters of galaxies harboured much more mass that that directly observable in optical wavelengths and that their members had undergone or were undergoing transformations that made their evolutionary path diverge from their counterparts in the field. To appropriately address those issues a key observable was demanded: accurate redshifts. However, that was found hard to get. On the one hand, photometric redshifts by themselves lack of the precision needed to establish whether a galaxy is within the cluster or not. On the other, spectroscopic redshifts are extremely demanding in terms of observation time and the selection of objects imply some a-priori criteria that may significantly bias the result, focusing in typical cluster members and eventually overlooking objects in the ends of the distribution function of luminosities and colors...
Download or read book Study of the Far Infrared Emission of Nearby Spiral Galaxies written by Willie Drouhet and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In my PHD work I explored the links between the physical properties of interstellar dust and other components of nearby spiral galaxies especially their stellar content. I worked on 46 disk galaxies from KINGFISH with IRAC/MIPS/PACS/SPIRE maps (3.6 - 500 microns). A bias is usually introduced in estimating disk orientations by using only a single surface brightness isophote. Thus I devised different surface brightness levels separated by constant steps in surface brightness and extracted isophotes at these levels in all FIR maps as well as in all IRAC 4.5 microns maps. To further assess the coherence of the shapes of isophotes across galactic disks, I built a quantitative indicator of the difference in shape between two ellipses with same center and same semi-major axis.I defined an acceptable level of difference between isophote shapes, by comparing disk orientations found in litterature. Using this level, I found regions inside the galactic disks where the isophotal shapes are similar. From these, I extracted one disk orientation per wavelength band. I found in the vast majority of the disk galaxy maps, be it dominated by stellar or dust emission, that a large fraction of the isophotes I extracted are coherent with the idea of an underlying disk. Comparing, for each galaxy, disk orientations extracted at all wavelengths, I found evidence in 20 galaxies out of 46, that on radial ranges as large as 1/3 of the visible disk (as measured by R25), the shapes of isophotes are morphologically similar. Thus for these 20 galaxies I devised consistent disk orientations both for the stellar and dust content. These 20 galaxies are less luminous, less emitting in the IR w.r.t. the optical, less barred, and characterized by later stage types than average. I also found that the disk orientations devised by my photometric method yield results more similar to H-alpha kinematic orientations than other photometric studies based on a single isophote level.Using the orientations I found and H-alpha dynamics disk orientations, I averaged azimuthally surface brightnesses to produce radial spectral energy distributions (SED) profiles. Once fitted with a cosmic dust emission model, they resulted in radial profiles of dust and stellar content properties. I found the dust intercepted power to be proportionnal to the product of the total dust mass and the average ISRF shining on dust. This former quantity is better correlated with the bolometric stellar luminosity than any of the dust mass or the dust heating ISRF separately. Thus the old stellar populations may be an important heating source for dust. The power intercepted by dust is also very well correlated with the total infrared power. The dust intercepts a larger quantity of power coming from stars in more actively star forming galaxies.Dust exhibit radial mass surface density profiles less well described by Sersic functions than stellar ones. When both profiles are well fitted by Sersic functions, stellar density profiles have smaller half mass radii than the isophotal optical radius (R25) separately in later type galaxies, but also in more quiescent galaxies. Sersic index and half mass radius distributions have larger widths for dust than for stellar surface density profiles.I also found that the ratio of dust over stellar surface density is an important factor to explain the variations with galactic morphological type of the ratio of dust intercepted power over the power emitted by old stellar populations. This later link could be intertwined with spiral structure strength in stage types later than 2.
Download or read book Clusters of Galaxies written by William R. Oegerle and published by Cambridge University Press. This book was released on 1990 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collected in this volume are the review papers from the Space Telescope Science Institute symposium on Clusters of Galaxies held in May 1989. Fifteen experts in the field have presented summaries of our current understanding of the formation and evolution of clusters and their constituent galaxies. Subjects covered include the existence and importance of subclustering, models of the evolution of clusters and the intracluster medium, the effect of the cluster environment on galaxies, observations of high redshift clusters, and the use of clusters as tracers of large scale structure. This book provides a timely focus for future observational and theoretical work on clusters of galaxies.
Download or read book Cooling Flows in Clusters and Galaxies written by A.C. Fabian and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 377 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray astronomers discovered the diffuse gas in clusters of galaxies about 20 years ago. It was later realized that the central gas density in some clusters, and in elliptical galaxies, is so high that radiative cooling is a significant energy loss. The cooling time of the gas decreases rapidly towards the centre of the cluster or galaxy and is less than a Hubble time within the innermost few hundred kiloparsecs. This results in a cooling flow in which the gas density rises in order to maintain pressure to support the weight of the overlying gas. The rate at which mass is deposited by the flow is inferred to be several hundreds of solar masses per year in some clusters. The fraction of clusters in which cooling flows are found may exceed 50 per cent. Small flows probably occur in most normal elliptical galaxies that are not in rich clusters. The implications of this simple phenomenon are profound, for we appear to be witnessing the ongoing formation of the central galaxy. In particular, since most of the gas is undetected once it cools below about 3 million K, it appears to form dark matter. There is no reason why it should be detectable with current techniques if each cooling proton only recombines once and the matter condenses into objects of low mass.
Download or read book More Things in the Heavens written by Michael Werner and published by Princeton University Press. This book was released on 2019-06-25 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A sweeping tour of the infrared universe as seen through the eyes of NASA’s Spitzer Space Telescope Astronomers have been studying the heavens for thousands of years, but until recently much of the cosmos has been invisible to the human eye. Launched in 2003, the Spitzer Space Telescope has brought the infrared universe into focus as never before. Michael Werner and Peter Eisenhardt are among the scientists who worked for decades to bring this historic mission to life. Here is their inside story of how Spitzer continues to carry out cutting-edge infrared astronomy to help answer fundamental questions that have intrigued humankind since time immemorial: Where did we come from? How did the universe evolve? Are we alone? In this panoramic book, Werner and Eisenhardt take readers on a breathtaking guided tour of the cosmos in the infrared, beginning in our solar system and venturing ever outward toward the distant origins of the expanding universe. They explain how astronomers use the infrared to observe celestial bodies that are too cold or too far away for their light to be seen by the eye, to conduct deep surveys of galaxies as they appeared at the dawn of time, and to peer through dense cosmic clouds that obscure major events in the life cycles of planets, stars, and galaxies. Featuring many of Spitzer’s spectacular images, More Things in the Heavens provides a thrilling look at how infrared astronomy is aiding the search for exoplanets and extraterrestrial life, and transforming our understanding of the history and evolution of our universe.
Download or read book X Ray Emission from Clusters of Galaxies written by Craig L. Sarazin and published by Cambridge University Press. This book was released on 1988-03-17 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: First published in 1988, this book is a comprehensive survey of the astrophysical characteristics of the hot gas which pervades clusters of galaxies. In our universe, clusters of galaxies are the largest organised structures. Typically they comprise hundreds of galaxies moving through a region of space ten million light years in diameter. The volume between the galaxies is filled with gas having a temperature of 100 million degrees. This material is a strong source of cosmic X-rays. Dr Sarazin describes the theoretical description of the origin, dynamics, and physical state of the cluster gas. Observations by radio and optical telescopes are also summarised. This account is addressed to professional astronomers and to graduate students. It is an exhaustive summary of a rapidly expanding field of research in modern astrophysics.
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 Far Infrared Supplement written by Daniel Y. Gezari and published by . This book was released on 1993 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: The catalog contains about 210,000 observations of roughly 20,000 individual sources, and supporting appendices. The literature search is complete for years 1965 through 1990.
Download or read book The Search for Extended Infrared Emission Near Interacting and Active Galaxies 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 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The following subject areas are covered: the search for extended far IR emission; the search for extended emission in galaxy groups; a brief review of the flattening algorithm; the target groups; extended emission from groups and intergalactic HI clouds; and morphological image processing. Appleton, Philip N. Unspecified Center NAG5-1186...
Download or read book 3K SN s Clusters Hunting the Cosmological Parameters with Precision Cosmology written by Domingos Barbosa and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: A JENAM 2002 Workshop, Porto, Portugal, 3-5 September 2002
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-06 with total page 1216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Gas Dust and Star Formation in Galaxies IAU S292 written by Tony Wong and published by Cambridge University Press. This book was released on 2013-04-11 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Our knowledge of the molecular gas content in galaxies has advanced rapidly in the past decade with systematic surveys from ground-based radio facilities, coupled with advances in observations and modeling of the thermal dust emission associated with the gas. This Symposium Proceedings provides a timely overview of the latest observations of molecular gas and dust in the Milky Way and in other galaxies. It also covers related topics including the initial conditions for star formation, observational tracers of star formation and interstellar conditions, and simulations of the turbulent, multiphase interstellar medium. Featuring ten review articles by leaders in the field, and including early results and prospects for the ALMA observatory, this volume will prove especially useful for graduate students or scientists who are pursuing or planning research in this area.
Download or read book Literature 1989 Part 1 written by Astronomisches Rechen-Institut and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1433 pages. Available in PDF, EPUB and Kindle. Book excerpt: From the reviews: "Astronomy and Astrophysics Abstracts has appeared in semi-annual volumes since 1969 and it has already become one of the fundemental publications in the fields of astronomy, astrophysics and neighbouring sciences. It is the most important English-language abstracting journal in the mentioned branches. ...The abstracts are classified under more than a hundred subject categories, thus permitting a quick survey of the whole extended material. The AAA is a valuable and important publication for all students and scientists working in the fields of astronomy and related sciences. As such it represents a necessary ingredient of any astronomical library all over the world." Space Science Review# "Dividing the whole field plus related subjects into 108 categories, each work is numbered and most are accompanied by brief abstracts. Fairly comprehensive cross-referencing links relevant papers to more than one category, and exhaustive author and subject indices are to be found at the back, making the catalogues easy to use. The series appears to be so complete in its coverage and always less than a year out of date that I shall certainly have to make a little more space on those shelves for future volumes." The Observatory Magazine#
