Morphology, Kinematics and Star Formation Across the Hubble Sequence of Galaxies PDF
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Springer Theses Recognizing Outstanding Ph.D. Research Santiago Erroz-Ferrer Morphology, Kinematics and Star Formation Across the Hubble Sequence of Galaxies Springer Theses Recognizing Outstanding Ph.D. Research Aims and Scope The series “Springer Theses” brings together a selection of the very best Ph.D. theses from around the world and across the physical sciences. Nominated and endorsed by two recognized specialists, each published volume has been selected foritsscientificexcellenceandthehighimpactofitscontentsforthepertinentfield of research. For greater accessibility to non-specialists, the published versions includeanextendedintroduction,aswellasaforewordbythestudent’ssupervisor explainingthespecialrelevanceoftheworkforthefield.Asawhole,theserieswill provide a valuable resource both for newcomers to the research fields described, and for other scientists seeking detailed background information on special questions. Finally, it provides an accredited documentation of the valuable contributions made by today’s younger generation of scientists. Theses are accepted into the series by invited nomination only and must fulfill all of the following criteria (cid:129) They must be written in good English. (cid:129) ThetopicshouldfallwithintheconfinesofChemistry,Physics,EarthSciences, Engineeringandrelatedinterdisciplinary fields such asMaterials,Nanoscience, Chemical Engineering, Complex Systems and Biophysics. (cid:129) The work reported in the thesis must represent a significant scientific advance. (cid:129) Ifthethesisincludespreviouslypublishedmaterial,permissiontoreproducethis must be gained from the respective copyright holder. (cid:129) They must have been examined and passed during the 12 months prior to nomination. (cid:129) Each thesis should include a foreword by the supervisor outlining the signifi- cance of its content. (cid:129) The theses should have a clearly defined structure including an introduction accessible to scientists not expert in that particular field. More information about this series at http://www.springer.com/series/8790 Santiago Erroz-Ferrer Morphology, Kinematics and Star Formation Across the Hubble Sequence of Galaxies Doctoral Thesis accepted by the University of La Laguna, Spain 123 Author Supervisor Dr. SantiagoErroz-Ferrer Prof. JohanKnapen Instituto deAstrofísicadeCanarias Instituto deAstrofísicadeCanarias University of LaLaguna University of LaLaguna SanCristóbal deLa Laguna SanCristóbal deLa Laguna Spain Spain and CaseWestern ReserveUniversity Cleveland, OH USA ISSN 2190-5053 ISSN 2190-5061 (electronic) SpringerTheses ISBN978-3-319-26397-7 ISBN978-3-319-26398-4 (eBook) DOI 10.1007/978-3-319-26398-4 LibraryofCongressControlNumber:2015954963 SpringerChamHeidelbergNewYorkDordrechtLondon ©SpringerInternationalPublishingSwitzerland2016 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfrom therelevantprotectivelawsandregulationsandthereforefreeforgeneraluse. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authorsortheeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinor foranyerrorsoromissionsthatmayhavebeenmade. Printedonacid-freepaper SpringerInternationalPublishingAGSwitzerlandispartofSpringerScience+BusinessMedia (www.springer.com) ’ Supervisor s Foreword Galaxies are the building blocks of the Universe, and the study of their formation and evolution is key to the understanding of how the Universe has acquired its presentshape. Ofparticularinterest isthedetailedstudy oftheinternal,or secular, evolution of galaxies. This describes the evolution induced by internal processes suchastheactionsofspiralarms,bars,ovals,galacticwinds,blackholes,anddark matter haloes. Secular evolution plays an important role in the evolution of spiral galaxies,and one key advantageis that one can study therelevant physics ingreat detail through observations of the nearest galaxies. This thesis describes a study of the morphology, kinematics, and star formation properties of carefully selected samples of nearby galaxies. The work is closely related to the Spitzer Survey of Stellar Structure of Galaxies (S4G), a mid-infrared imaging study of some 3000 nearby galaxies. This Survey has provided accurate measurements of many basic parameters of the sample galaxies, such as morpho- logical type, stellar mass, and the presence of structural components such as bars, lenses, or rings. In the context of this thesis, a subsample of 29 galaxies was selected from the overall sample for follow-up study, and observed with two dif- ferent instruments on the 4.2 m William Herschel Telescope in La Palma: ACAM and GHαFAS. With those, imaging in the Hα line and Fabry-Perot spectroscopy was obtained, to derive star formation rates and gas kinematics, respectively. Among the main results of the thesis is the study of correlations of kinematic parameters of the sample galaxies, such as the central slope of the rotation curve, with the overall parameters of the galaxies and their spiral arms and bars. A fundamental advance here is that a sample of 29 galaxies was used, spanning a wide range in morphological type, stellar mass, and bar and spiral properties, and that kinematic data at high spatial and spectral resolution were obtained for all of them. In combination with the accurate parameters yielded by the S4G survey, important results are obtained on streaming and other non-circular motions in galaxies, on the distribution and rates of star formation, and on how correlations of these parameters and of the rotation curve shape with basic galaxy parameters yield clues on the evolutionary processes taking place in disk galaxies. The data v vi Supervisor’sForeword obtained for this project have all been made public, and form part of the lasting legacy of this work. This thesis work, carried out between September 2010 and October 2014 at the University of La Laguna and the Instituto de Astrofísica de Canarias, has led to a number of publications in refereed journals and presentations at international conferences. The thesis was defensed at the Aula Magna of the Physics Faculty of the University of La Laguna (Tenerife, Spain), and was honoured Summa Cum Laude. San Cristóbal de La Laguna Prof. Johan Knapen July 2015 Preface The topic of this thesis is the study of the morphology, kinematics, and star for- mation of nearby galaxies, aiming to clarify a number of long-standing open questions about their formation, evolution, and physical properties. First, I have addressed the star formation and its distribution across the Hubble sequence of galaxies. In particular, I have studied massive star formation in ellip- tical, lenticular, and early-type galaxies. Although these galaxies have generally low gas content and low levels of star formation, there is a significant subset that shows evidence of ongoing star formation in the form of extended UV emission. I have obtained Hα imaging of ten such galaxies, finding that in most cases, their starformationratesarecomparabletothosefoundindiskgalaxies.Thisisprobably because the sample selection is biased toward star-forming galaxies. I confirm that massivestarformationcausestheextendedUVemissioninoursample,intheform of outer spiral arms and/or outer (pseudo) rings. This thesis has been developed in the context of the Spitzer Survey of Stellar StructureinGalaxies(S4G),whichhasobtainedmid-IRimagesofmorethan2350 galaxies in the local Universe. These images and the studies within the S4G col- laboration have been complemented with the ancillary kinematic data obtained within the framework of this thesis. I present a kinematical study of 29 spiral galaxiesincludedintheS4Gsample,usingHαFabry-Perot(FP)dataobtainedwith theGalaxyHαFabry-PerotSysteminstrumentattheWilliamHerschelTelescopein LaPalma,complementedwithimagesintheRbandandinHα.Theprimarygoalis tostudytheevolutionandpropertiesofthemainstructuralcomponentsofgalaxies through the kinematical analysis of the FP data, complemented with studies of morphology, star formation, and mass distribution. In this thesis, I describe how these data have been obtained, processed, and analyzed. This program of 3D kinematicsenables thestudy of themotions oftheionized gaswithinthe galaxies, including in-depth investigations of the rotation curves, velocity moment maps, velocity residual maps, and position–velocity diagrams. Galaxy disks are supported by rotation to minimize the total energy when conserving the angular momentum. However, through the evolution of a galaxy, vii viii Preface several processes interfere on the kinematics of the galaxy and provoke deviations from the pure rotation, what we call non-circular motions. In particular, non-axisymmetric structures such as bars are understood to create potentials that influence the way material move toward the center of the galaxy. As a first step to understandthenon-circularmotions,Ipresentdetailedresultsonthebarredgalaxy NGC864fromthekinematicalprogram.Ifindasymmetriesinthevelocityfieldin thebarzone,causedbynon-circularmotions,probablyinresponsetothepotential of the bar. Thestudyregardingthenon-circularmotionsisexpandedtothewholesampleof galaxies.Inparticular,thosemotionsfoundalongthebarsandspiralarms.Thedata indicatethattheamplitudeofthenon-circularmotionscreatedbythebarintheHα gas does not correlate with the strength of the bar. The amplitude of those non- circularmotionsrelatedtothespiralarmsdoesnotcorrelatewitheitherarmclassor star formation rate along the spiral arms. This implies that the presence and mag- nitude of streaming motions in the arms seem to be a local phenomenon. I also study here the global SFRs of the galaxies of the sample, and in particular the star formation within the bar and its relationship with its kinematics. The dynamics in the central parts of galaxies are influenced by both baryonic matter(gasandstars)andDM.Thisthesiswilltrytofindoutwhichcontributionis more important regarding the dynamics of the central parts of the galaxy. Taking advantage of the high angular and spectral resolution of the kinematic data, I perform a detailed study of the shape of the innermost part of the rotation curve of the sample galaxies. In particular, I quantify the steepness of the rotation curve bymeasuringitsslope.Aspreviouslynotedintheliteratureand,infact,physically intuitive, I find that the compactness of the mass in the central parts of a galaxy (more concretely, the presence of the bulge) is translated into steeper slopes. Otherwise,Ifindnoinfluenceofthedegreeofsecularevolutionofagalaxyonthe value of the slope, as the presence of the bar and the star formation rate does not correlate with the slope. I find that although the luminous matter dominates the gravitationalpotentialinthecentralpartsofthegalaxies,darkmatterisalsopresent. Acknowledgments IwouldliketothankJohanKnapen,RyanLeaman, MauricioCisternas,andBarry Madore for his comments and suggestions during the preparation of this thesis. I would like to thank Inma Martínez Valpuesta for her suggestions as the referee ofthethesis.IwouldliketothankJoanFontandJoséRamónSánchez-Gallegofor their assistance with the reduction and calibration of the FP and Hα data. I would like to thank the Carnegie Observatories for hospitality and facility support. The thesis is based on observations made with the NOT and WHT operated on the island of La Palma, in the Spanish Observatorio del Roque de Los Muchachos oftheInstitutodeAstrofísicadeCanarias.Thedatapresentedherewereobtainedin partwithALFOSC,whichisprovidedbytheInstitutodeAstrofísicadeAndalucia under a joint agreement with the University of Copenhagen and NOTSA. Some of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and contracts. I thank the entire S4G team for their efforts in this project. This research has made use of the HyperLeda database (http://leda.univ-lyon1.fr) and the NASA/IPAC Extragalactic Database (NED), which is operated by JPL, Caltech, under contract with NASA. ix
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