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Université De Montréal Et Université De Provence Cinématique Et Université de Montréal et Université de Provence Cinématique et dynamique des galaxies spirales barrées par Olivier Hernandez Thèse effectuée en cotutelle au Département de Physique Faculté des arts et des sciences Université de Montréal et au Laboratoire d’Astrophysique de Marseille Université de Provence Thèse présentée à la Faculté des études supérieures de l’Université de Montréal en vue de l’obtention du grade de Phi1osophi Doctor (Ph.D.) en Physique et à l’Université de Provence en vue de l’obtention du grade de Docteur de l’Université de Provence Décembre, 2004 ©Olivier Hernandez, 2004 Oc u 5 P005 ,e10 Université dl1 de Montréal Direction des bibliothèques AVIS L’auteur a autorisé l’Université de Montréal à reproduire et diffuser, en totalité ou en partie, par quelque moyen que ce soit et sur quelque support que ce soit, et exclusivement à des fins non lucratives d’enseignement et de recherche, des copies de ce mémoire ou de cette thèse. L’auteur et les coauteurs le cas échéant conservent la propriété du droit d’auteur et des droits moraux qui protègent ce document. Ni la thèse ou le mémoire, ni des extraits substantiels de ce document, ne doivent être imprimés ou autrement reproduits sans l’autorisation de l’auteur. Afin de se conformer à la Loi canadienne sur la protection des renseignements personnels, quelques formulaires secondaires, coordonnées ou signatures intégrées au texte ont pu être enlevés de ce document. Bien que cela ait pu affecter la pagination, il n’y a aucun contenu manquant. NOTICE The author of this thesis or dissertation has granted a nonexclusive license allowing Université de Montréal to reproduce and publish the document, in part or in whole, and in any format, solely for noncommercial educational and research purposes. The author and co-authors if applicable tetain copyright ownership and moral rights in this document. Neither the whole thesis or dissertation, nor substantial extracts from it, may be printed or otherwise reproduced without the author’s permission. In compliance with the Canadian Privacy Act some supporting forms, contact information or signatures may have been removed from the document. While this may affect the document page count, t does flot represent any loss of content from the document. Université de Montréal Faculté des études supérieures et Laboratoire d’Astrophysique de Marseille Université de Provence Cette thèse intitulée Cinématique et dynamique des galaxies spirales barrées présentée et soutenue à l’Université de Montréal par Olivier Hernandez a été évaluée par un jury composé des personnes suivantes Anthony Moffat, Président-rapporteur et membre du jury (Université de Montréal) Claude Carignan, Directeur de recherche (Université de Montréal) Philippe Amram, Directeur de recherche (Université de Provence) Jacques Boulesteix, Membre du jury (Université de Provence) Françoise Combes, Examinateur externe (Observatoire de Paris) Paul Arminjon, Représentant du Doyen de la FES Thèse acceptée le 21 février 2005 Résumé La masse totale (lumineuse et non lumineuse) des galaxies est déduite de la vitesse circulaire de rotation des galaxies. L’observation spectroscopique de type Fabry-Perot du gaz ionisé des galaxies spirales permet d’obtenir leur cinématique. Dans le cas de champs de vitesses parfaitement axisymétriques - c’est à dire pour des galaxies spirales non barrées et non actives - ces champs de vitesses donnent directement accès à la composante circulaire de la vitesse de rotation. Les champs de vitesses des galaxies barrées sont plus complexes et ont besoin d’une analyse plus poussée pour en déduire leur vitesse circulaire. Or, les galaxies spirales barrées constituent plus des deux tiers des galaxies spirales. Une étude à grande échelle sur un échantillon de spirales barrées est donc nécessaire pour comprendre les mouvements non circulaires dans les galaxies. Cette thèse propose les moyens nécessaires pour rechercher la composante axi symétrique des galaxies spirales. L’accent a d’abord été mis sur une instrumentation de haute qualité, en développant FANTOMM, la caméra à comptage de photons la plus sensible au monde couplée à un interféromètre de Fabry-Perot. Dans un premier temps, l’analyse des données d’observation - d’un échantillon rigoureusement choisi de spirales barrées BHùBAR - a permis d’obtenir des champs de vitesses de grande qualité. Par la suite, la méthode de Tremaine-Weinberg, surtout utilisée jusqu’à maintenant avec la composante stellaire et qui permet de déterminer la fréquence de rotation de la barre dans une galaxie, a été utilisée sur ces données Hù et s’est révélée également efficace avec la composante de gaz ionisé. Enfin tous les éléments précédents ont permis d’étudier, parmi les galaxies de l’échantillon BHcBAR, des éléments clés de leur évolution - résonances des orbites, fréquences de rota tion des barres, ondes stationnaires multiples,... - qui permettront, grâce aux modèles N corps+SPH développés en parallèle, de déterminer beaucoup plus précisément la masse de galaxies spirales barrées. - Mots clés : Instrumentation astronomique Caméra à comptage de photons - RÉSUMÉ - - Spectroscopie 3D Interférométrie Fabry-Perot Évolution des galaxies spirales barrées - Cinématique - Dynamique - Modélisation N-coprs+SPH. S ummary The total mass (luminous and dark) of galaxies is derived from their circular veloci ties. Spectroscopic Fabry-Perot observations of the ionized gas component of spiral galaxies allow one to derive their kinematics. In the case of purely axisymmetric velocity fields - as in non-active and unbarred spirals galaxies - the circular velocities can be derived directly. Ho wever, the velocity fields of barred galaxies (which constitute two thirds of the spirals) exhibit strong non-circular motions and need a careful analysis to retrieve the circulai component. This thesis proposes the necessary steps to recover the axisymmetric component of barred spiral galaxies. The first step was to develop the best instrumentation possible for this work. FANTOMM, which is the most sensitive photon counting camera ever developed, was coupled to a Fabry-Perot interferometer. The observations of a sample of barred spiral galaxies - the BHcBAR sample - was assembled in order to obtain the most rigourous velocity fields. Then, the Tremaine-Weinberg method, which can determine the bar pattern speed and is usually used with the observations of stellar component, lias been tested on the ionised gas and gave satisfactory results. Finally, all the above techniques have been applied to the BHcBAR sample in order to study the key parameters of the galaxies’ evolution - bar pattern speeds, multiple stationary waves, resonances etc... - which will allow one to use N body+SPH simulations to model properly the non-circular motions and determine the true total mass of barred spiral galaxies. - Keywords : Astronomical instrumentation Photon counting system - 3D Spectroscopy - - Fabry-Perot Interferometer Evolution of bar spiral galaxies - Kinematics - Dynamics - N-coprs+SPH modelling. Remerciements Mes premiers remerciements vont tout naturellement à mes deux directeurs de thèse Claude Carignan et Philippe Amram, qui ont toujours été présents au cours de ce doctorat et m’ont sincèrement soutenu sur divers plans (universitaire, moral, financiers, ...). Merci beaucoup, j’espère vivement que nous auront encore beaucoup de projets en commun. Je voudrais aussi profiter de cette occasion pour remercier les personnes avec qui j’ai travaillé et qui ont contribué à la qualité de ce travail. D’abord, ceux de Montréal, Oli vier II et Laurent, votre aide et savoir précieux nous ont permis d’aller plus loin et de mieux comprendre la physique des Galaxies. Marie-Maude et Damien, merci pour votre disponi bilité et vos savoir-faire respectifs. Enfin, merci à Sébastien pour les longues discussions et les perspectives de carrière... Ensuite, je ne voudrais pas oublier le soutien et la collabora tion avec l’équipe de l’Observatoire de Marseille. Jean-Luc et Jacques, c’est un plaisir de travailler avec vous, même à 2500 m d’altitude. Michel, Philippe B., Olivier B. et Olivia, je vous remercie aussi pour votre expérience utilisée à juste profit dans ce travail. Hervé, de l’Observatoire de Lyon, je tiens aussi à te remercier pour m’avoir reçu plusieurs fois et partager tes expériences théoriques et multiprocesseurs. Enfin, une mention spéciale pour Chantal B., de l’Observatoire de Paris, pour ton enthousiasme inégalable même à 4500 m d’altitude! V” Table des matières Résumé iii Summary y Remerciements vi Liste des tableaux xi Liste des figures xii Abréviations xv Introduction 1 1 Du photon à la corotation 4 1.1 Instrumentation 5 1.1.1 Beaucoup de bruit pour rien 5 1.1.2 L’interféromètre Fabry-Perot et le comptage de photons 9 1.1.3 FANTOMM 12 1.2 Champs de vitesses et modèles de masse 14 1.2.1 Composantes d’une galaxie 14 1.2.2 Les différentes formes de l’hydrogène 15 1.2.3 Les champs de vitesses 16 1.2.4 Problématique des champs non axisymétriques 17 1.3 Les galaxies spirales barrées 20 1.3.1 Approximation des épicycles 23 1.3.2 La méthode de Tremaine-Weinberg 30 1.4 Dynamique numérique des galaxies 33 TABLE DES MATIÈRES viii 1.4.1 Problèmes à N-corps 33 1.4.2 Code hydrodynamique - SPH 36 1.4.3 Codes couplés étoiles-gaz 37 1.4.4 GADGET 38 1.4.5 La science en mouvement 39 2 FaNTOmN: Le Fabry-Perot au sommet de son art 41 2.1 Introduction 43 2.2 Basic considerations about the use of IPCSs with multiplex instruments . 44 2.2.1 Photon counting systems vs CCDs : the readout noise
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