Download or read book Les abondances chimiques dans les galaxies spirales de type pr coce written by Yvan Dutil and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Les abondances chimiques dans les galaxies spirales de type pr coce written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Les gradients d abondances chimiques dans les galaxies spirales barr es written by Pierre Martin (astronome).) and published by . This book was released on 1992 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book EVOLUTION CHIMIQUE ET SPECTRO PHOTOMETRIQUE DES GALAXIES SPIRALES written by SAMUEL.. BOISSIER and published by . This book was released on 2000 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE THESE PRESENTE UN MODELE D'EVOLUTION CHIMIQUE ET SPECTRO-PHOTOMETRIQUE COHERENT POUR L'ENSEMBLE DES GALAXIES SPIRALES. DANS UNE PREMIERE ETAPE, NOUS AVONS MODELISE LA VOIE LACTEE POUR LAQUELLE LES NOMBREUSES OBSERVABLES PERMETTENT DE CONTRAINDRE LES PARAMETRES DU MODELE (EFFICACITE DE LA FORMATION STELLAIRE, TEMPS CARACTERISTIQUE DE FORMATION DU DISQUE, ETC). NOUS AVONS ENSUITE GENERALISE LE MODELE DE LA VOIE LACTEE A UNE SPIRALE QUELCONQUE EN INVOQUANT DEUX PARAMETRES : LA VITESSE DE ROTATION DE LA GALAXIE, ET SON PARAMETRE DE SPIN. LE SEUL DEGRE DE LIBERTE DE CETTE GENERALISATION CONCERNE LE TEMPS CARACTERISTIQUE DE L'INFALL (FORMATION PAR APPORT PROGRESSIF DE GAZ PRIMORDIAL). NOUS AVONS ETABLI QUE POUR REPRODUIRE UN LARGE ENSEMBLE D'OBSERVATIONS, IL EST INDISPENSABLE DE SUPPOSER QUE LES DISQUES BARYONIQUES DES GALAXIES MASSIVES SE SONT FORMES PLUS RAPIDEMENT QUE CEUX DES GALAXIES DE FAIBLE MASSE. L'ANALYSE D'UN ENSEMBLE HOMOGENE DE DONNEES MULTI-LONGUEUR D'ONDE NOUS A PERMIS DE CONFIRMER LA NECESSITE DE CETTE HYPOTHESE. LA GRILLE DE MODELES AINSI OBTENUE EST COMPATIBLE AVEC L'ENSEMBLE DES OBSERVATIONS DISPONIBLES POUR LES GALAXIES PROCHES. ELLE REPRODUIT AUSSI LES GRADIENTS D'ABONDANCE ET DE COULEUR QUE L'ON PEUT OBSERVER DANS CELLES-CI. NOUS AVONS EN PARTICULIER MIS EN EVIDENCE UNE CORRELATION ENTRE LA VALEUR DU GRADIENT D'ABONDANCE ET L'INVERSE DU RAYON CARACTERISTIQUE DU DISQUE STELLAIRE. NOUS AVONS VERIFIE QUE LES PREDICTIONS CONCERNANT L'EVOLUTION DE NOS MODELES SONT EN ACCORD AVEC LES OBSERVATIONS DE SPIRALES A REDSHIFT ELEVE (INFERIEUR A 1). NOUS AVONS AUSSI VERIFIE QU'UNE FOIS LES BIAIS OBSERVATIONNELS PRIS EN COMPTE, LES PREDICTIONS DES MODELES SONT COMPATIBLES AVEC L'HYPOTHESE SELON LAQUELLE LES SYSTEMES ABSORBANTS LORENTZIENS DANS LES SPECTRES DES QUASARS SONT LES PRECURSEURS DES GALAXIES SPIRALES.
Download or read book Etude de l volution chimique et dynamique d objets proto galactiques written by Sébastien Poirier and published by . This book was released on 2004 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse traite de l'évolution des galaxies. Afin de comprendre la nature évolutive des galaxies spirales, nous étudions les relations entre la chimie et la dynamique. Nous avons mis en place une étude numérique couplant chimie et dynamique dans un schéma totalement auto-gravitant, auto-cohérent et tridimensionnel, et incluant l'enrichissement chimique en Fer, Oxygène et Magnésium, dû aux supernovae de type Ia et de type II. Afin d'aborder la question de l'évolution intrinsèque d'une galaxie, nous considérons une famille d'objets proto-galactiques conduisant par effondrement monolithique à la formation de disque galactique. La caractérisation morphologique, cinématique et chimique de ces objets montre la validité d'une telle approche. Ces galaxies développent une structure spirale due à l'onde densité induit par la présence d'une barre possédant une faible structure boîte/cacahuète. Nous ne constatons pas la croissance d'un bulbe sur la durée des simulations. Nous montrons que ces galaxies présentent des gradients d'abondances et une population stellaire unique. Nous en concluons la nécessité de phénomènes extrinsèques aux galaxies pour expliquer les différentes populations stellaires.Par ailleurs, nous sommes impliqués dans la photométrie et la spectroscopie d'amas de galaxies distants du projet EDisCS. Nous avons eu l'importante responsabilité de la réalisation des masques spectroscopiques pour l'instrument VLT-FORS2 par la mise en œuvre d'un programme de sélection automatique des galaxies devant être observées. Nous avons de plus développé un programme de décomposition bidimensionnelle du profil de luminosité des galaxies.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1997 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1998 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Information Bulletin written by and published by . This book was released on 1999 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book De la m tallicit et la formation stellaire des galaxies spirales barr es written by Christian Carles and published by . This book was released on 2016 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Afin d'étudier l'historique de formation stellaire et d'enrichissement chimique des galaxies spirales barrées, j'ai simulé l'évolution de 27 galaxies spirales, barrées et non barrées, de diverses masses stellaires et fractions de gaz. Alors que les galaxies non barrées présentent une évolution lente et continue sur les deux milliards d'années que durent nos simulations, les galaxies barrées ont une évolution bien plus explosive, et ce particulièrement pour les galaxies les plus massives. Dans un premier temps, je montre que la présence de la barre entraine un flot important de gaz des régions périphériques vers le centre de la galaxie barrée, causant un sursaut de formation stellaire et une croissance importante de l'abondance chimique centrale, et que l'amplitude et la vitesse à laquelle ce sursaut arrive augmentent avec la masse de la galaxie. Cet épisode de sursaut stellaire entraine alors une diminution importante de la masse de gaz, entrainant à son tour une décroissance de la formation stellaire et une stagnation de l'enrichissement chimique pour le reste de l'évolution de la galaxie. Dans un deuxième temps, je montre qu'à cause de la dynamique en deux périodes très différentes des galaxies barrées, deux galaxies de masse très semblable peuvent avoir des taux de formation stellaire et des métallicités complètement différentes en fonction de leur stade évolutif, stade qu'on ne peut déterminer aisément. Cette difficulté est tout aussi importante lorsqu'on compare le coeur des galaxies barrées et non barrées entre elles, étant donné que des coeurs comparables sont situés dans les galaxies très différentes, et que des galaxies semblables ont des coeurs très différents.
Download or read book The Journal of the Royal Astronomical Society of Canada written by Royal Astronomical Society of Canada and published by . This book was released on 1998 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Library catalogue in 1911" (31 p.) appended to v. 4.
Download or read book A Frequency Dictionary of French written by Deryle Lonsdale and published by Routledge. This book was released on 2009-03-25 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Frequency Dictionary of French is an invaluable tool for all learners of French, providing a list of the 5000 most frequently used words in the language. Based on a 23-million-word corpus of French which includes written and spoken material both from France and overseas, this dictionary provides the user with detailed information for each of the 5000 entries, including English equivalents, a sample sentence, its English translation, usage statistics, and an indication of register variation. Users can access the top 5000 words either through the main frequency listing or through an alphabetical index. Throughout the frequency listing there are thematically-organized lists of the top words from a variety of key topics such as sports, weather, clothing, and family terms. An engaging and highly useful resource, the Frequency Dictionary of French will enable students of all levels to get the most out of their study of French vocabulary. Former CD content is now available to access at www.routledge.com/9780415775311 as support material. Designed for use by corpus and computational linguists it provides the full text in a format that researchers can process and turn into suitable lists for their own research work. Deryle Lonsdale is Associate Professor in the Linguistics and English Language Department at Brigham Young University (Provo, Utah). Yvon Le Bras is Associate Professor of French and Department Chair of the French and Italian Department at Brigham Young University (Provo, Utah).
Download or read book A New Pocket Dictionary of the French and English Languages in Two Parts written by Thomas Nugent and published by . This book was released on 1770 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stellar Pulsation written by and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The X ray Universe written by Wallace H. Tucker and published by . This book was released on 1985 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Beyond the range of optical perception--and of ordinary imaginings--a new and violent universe lay undetected until the advent of space exploration. Supernovae, black holes, quasars and pulsars--these were the secrets of the highenergy world revealed when, for the first time, astronomers attached their instruments to rockets and lofted them beyond the earth's x-ray-absorbing atmosphere. The X-Ray Universe is the story of these explorations and the fantastic new science they brought into being. It is a first-hand account: Riccardo Giacconi is one of the principal pioneers of the field, and Wallace Tucker is a theorist who worked closely with him at many critical periods. The book carries the reader from the early days of the Naval Research Laboratory through the era of V-2 rocketry, Sputnik, and the birth of NASA, to the launching of the Einstein X-Ray Observatory. But this is by no means just a history. Behind the suspenseful, sometimes humorous details of human personality grappling with high technology lies a sophisticated exposition of current cosmology and astrophysics, from the rise and fall of the steady-state theory to the search for the missing mass of the universe.
Download or read book An Introduction to Differential Manifolds written by Jacques Lafontaine and published by Springer. This book was released on 2015-07-29 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is an introduction to differential manifolds. It gives solid preliminaries for more advanced topics: Riemannian manifolds, differential topology, Lie theory. It presupposes little background: the reader is only expected to master basic differential calculus, and a little point-set topology. The book covers the main topics of differential geometry: manifolds, tangent space, vector fields, differential forms, Lie groups, and a few more sophisticated topics such as de Rham cohomology, degree theory and the Gauss-Bonnet theorem for surfaces. Its ambition is to give solid foundations. In particular, the introduction of “abstract” notions such as manifolds or differential forms is motivated via questions and examples from mathematics or theoretical physics. More than 150 exercises, some of them easy and classical, some others more sophisticated, will help the beginner as well as the more expert reader. Solutions are provided for most of them. The book should be of interest to various readers: undergraduate and graduate students for a first contact to differential manifolds, mathematicians from other fields and physicists who wish to acquire some feeling about this beautiful theory. The original French text Introduction aux variétés différentielles has been a best-seller in its category in France for many years. Jacques Lafontaine was successively assistant Professor at Paris Diderot University and Professor at the University of Montpellier, where he is presently emeritus. His main research interests are Riemannian and pseudo-Riemannian geometry, including some aspects of mathematical relativity. Besides his personal research articles, he was involved in several textbooks and research monographs.
Download or read book Aeronomy written by P. M. Banks and published by Elsevier. This book was released on 2013-09-24 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aeronomy, Part A is an attempt to make a comprehensive exposition of the processes in aeronomy, the study of composition, movement, and thermal balance of the upper regions of the planetary atmosphere. The text covers topics such as atmospheric regions and atmospheric density, the temperature and molecular mass of the atmosphere; the permanent constituents and the molecular and isotonic composition of the homosphere; and the transition from the homosphere to the heterosphere. Also covered are topics such as the temperature gradient and energies in the thermosphere, conditions at 200km and above 250km, solar radiation and ionization, and aeronomic reactions. The book is recommended for scientists, especially natural physicists, who would like to know more about the field of aeronomy and its advances.
Download or read book Pronunciation of the French language written by Félix Émile Darqué and published by . This book was released on 1859 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
