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Proquest Dissertations EXPLORING THE NEUTRAL HYDROGEN DISTRIBUTION AND THE GAS-RICH DWARF GALAXY POPULATION IN THE INTERACTING GALAXY GROUP NGC 3166/9 ETUDE DE LA DISTRIBUTION D'HYDROGENE NEUTRE ET DE LA POPULATION DE GALAXIES NAINES RICHES EN GAZ DU GROUPE DE GALAXIES EN INTERACTION NGC 3166/9 A Thesis Submitted to the Division of Graduate Studies of the Royal Military College of Canada by Karen Li Guen Lee-Waddell, BSc, BA Sub-Lieutenant In Partial Fulfilment of the Requirements for the Degree of Master of Science in Physics August 2011 © This thesis may be used within the Department of National Defence but copyright for open publication remains the property of the author. Library and Archives Bibliotheque et 1*1 Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington OttawaONK1A0N4 OttawaONK1A0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-82214-2 Our file Notre reference ISBN: 978-0-494-82214-2 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lnternet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distribute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non­ support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation. without the author's permission. In compliance with the Canadian Conformement a la loi canadienne sur la Privacy Act some supporting forms protection de la vie privee, quelques may have been removed from this formulaires secondaires ont ete enleves de thesis. cette these. While these forms may be included Bien que ces formulaires aient inclus dans in the document page count, their la pagination, il n'y aura aucun contenu removal does not represent any loss manquant. of content from the thesis. 1+1 Canada dedicated to my mother to live in our hearts is not to die Acknowledgements This thesis would not have been possible without the support of many people. First and foremost, I wish to express my sincere gratitude to my supervisor, Dr. Kristine Spekkens, who was abundantly helpful and offered invaluable assistance, support and guidance. My thanks and appreciation goes to all my friends, classmates and colleagues for their continued help and wishes for the successful completion of this project. A special thanks goes to Poonam Chandra for the invaluable tutorials in AIPS, Sabrina Stierwalt for her assistance with the observations, Jayaram Chengalur for the much appreciated technical advice and Martha P. Haynes for providing the ALFALFA data. I would like to thank the staff of the GMRT who have made the observations in this work possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. Finally, I would like to express my heartfelt thanks to my family, for their never ending support and encouragement, and to my husband, for always ensuring that my sky does not fall. ii Abstract Lee-Waddell, Karen Li Guen. MSc. Royal Military College of Canada, July 2011. Exploring the Neutral Hydrogen Distribution and the Gas-rich Dwarf Galaxy Population in the Interacting Galaxy Group NGC 3166/9. Supervised by Dr. Kristine Spekkens. In order to quantify the membership, properties and nature of the gas- rich dwarf galaxy population in the interacting galaxy group NGC 3166/9 - previously shown by the Arecibo Legacy Fast ALFA survey (ALFALFA) to have extensive neutral hydrogen (H i) emission in and around its core region - high-resolution H I observations have been obtained using the Giant Metre- wave Radio Telescope (GMRT). The GMRT data recovers less than 40% of the H I flux detected by ALFALFA suggesting that there is a broadly distributed intergalactic component to the H I emission. A thorough search of the GMRT datacube revealed eight dwarf galaxy candidates with gas masses ranging from 4 to 31 x 107 MQ, dynamical masses up to 14 x 108 M© and stellar masses ranging from 0.2 to 2 x 107 MQ. Most of these dwarfs are likely to be pri­ mordial dwarf irregular galaxies; however, one candidate is clearly associated with a prominent tidal feature below NGC 3166 and is a probable tidal dwarf galaxy with a dynamical to gas mass ratio close to unity. These results are in­ tegral to understanding galaxy formation and evolution in group environments. Keywords: galaxy group interactions, neutral hydrogen, tidal dwarf galaxy in Resume Lee-Waddell, Karen Li Guen. MSc. College Militaire Royal du Canada, Juillet 2011. Etude de la Distribution d'Hydrogene Neutre et de la Population de Galaxies Naines Riches en Gaz du Groupe de Galaxies en Interaction NGC 3166/9. These dirigee par Dr. Kristine Spekkens. L'objectif de ce projet etait d'etudier l'appartenance, les proprietes et l'origine de la population de galaxies naines riches en gaz du groupe NGC 3166/9. Precedemment, VArecibo Legacy Fast ALFA Survey (ALFALFA) avait mesure une grande quantite d'hydrogene neutre (H i) dans la region centrale de ce groupe en interaction. Pour la presente etude, des observations a tres haute resolution de la raie d'emission H I ont ete obtenues au Giant Meter- wave Radio Telescope (GMRT). Ces donnees contiennent moins de 40% du flux detecte par ALFALFA, ce qui suggere l'existence d'une composante en emission a grande echelle, distribute a travers le groupe. Suite a une analyse plus approfondie du cube de donnees du GMRT, huit galaxies naines poten- tielles ont ete recensees. Ces candidates possedent une masse gazeuse comprise entre 4 et 31 x 107 M©, une masse dynamique allant jusqu'a 14 x 108 M© ainsi qu'une masse stellaire entre 0.2 et 2 x 107 M©. La plupart de ces objets sont probablement des galaxies naines irregulieres primordiales. Cependant, Fun d'entre eux est manifestement affecte par la force de maree exercee par NGC 3166. II s'agirait d'une galaxie naine de maree possedant un rapport de la masse dynamique a la masse de gazeuse proche de un. Ces resultats sont es- iv sentiels a la comprehension des mecanismes de formation et d'evolution des galaxies dans un environnement de groupe. Mots cles: groupe de galaxies en interaction, hydrogene neutre, galaxie naine de maree v Table of Contents 1 Introduction 1 1.1 Galactic Properties 1 1.1.1 Dwarf Galaxies 2 1.1.2 Luminous and Dark Galaxy Components 3 1.2 Galaxy Groups and Interactions 7 1.2.1 Tidal Dwarf Galaxies 9 1.3 Neutral Hydrogen 11 1.4 Literature Review: NGC 3166/9 14 2 Radio Astronomy 18 2.1 Flux Density 18 2.2 Radio Antenna Properties 19 2.3 Interferometry 23 2.4 Editing and Calibration 25 2.5 Imaging 26 3 Data Reduction 29 3.1 Obtaining Data from the GMRT 29 3.2 Data Reduction using AIPS 32 3.3 Imaging in AIPS 33 4 H I in the NGC 3166/9 Group 41 vi 4.1 H I Detections 41 4.2 Flux Density Measurements and H I Masses 56 4.3 Dynamical Masses 59 4.4 H I Results 60 5 SDSS & GALEX Observations of NGC 3166/9 63 5.1 Stellar Masses from SDSS Data 63 5.2 Star Formation Rates from GALEX Data 68 5.3 SDSS & GALEX Results 73 6 Discussion 76 6.1 Comparison to the Local Group 77 6.2 Tidal Dwarf Galaxy Candidates 78 6.3 Dwarf Galaxy Comparisons 82 6.4 Notes on Individual Dwarf Galaxies 84 7 Conclusion 87 7.1 Future Work 88 Bibliography 91 A Calculations 96 Detection Limit Calculations 96 Global Profile Calculations 98 B Channel Maps 99 Curriculum Vitae 107 vn List of Tables 3.1 GMRT Observation Setup and Image Properties 31 4.1 Coordinates of Sources Identified in the GMRT Data 43 4.2 H I Masses from the GMRT Data 58 4.3 H I Masses from the ALFALFA Data 59 4.4 Dynamical Masses from the GMRT Data 62 5.1 Stellar and Baryonic Mass Estimates from Archival SDSS Data 67 5.2 GALEX FUV Star Formation Rates 72 5.3 GALEX NUV Star Formation Rates 73 5.4 Summary of Results for the Dwarf Galaxy Candidates 75 vni List of Figures 1.1 Hubble sequence of galaxies (Ville Koistinen). Spirals are di­ vided into those with (SBa, SBb, and SBc) and those without (Sa, Sb, Sc) bars and then classified based on the appearance of their arms. Ellipticals are denoted by the letter E followed by an integer that represents their degree of ellipticity. SOs, known as lenticulars, consist of a bright central bulge surrounded by a disk-like, non-spiral structure making them true hybrids of both morphologies 2 ix Multi-wavelength images - at approximately the same linear scale - of M51, the "Whirlpool Galaxy", consisting of a large Sa spiral (M51a) and its dwarf companion (M51b): a) Chan­ dra X-ray image of hot material around black holes, neutron stars and binary systems (NASA/CXC/Wesleyan/R.Kilgard); b) Galaxy Evolution Explorer (GALEX) ultraviolet image of young, massive stars (NASA/JPL-Caltech); c) Hubble Space Telescope (HST) optical image of the stellar population par­ tially shrouded by dust (NASA/ESA/S.
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