On the Prevalence of Starbursts in Dwarf Galaxies Item Type text; Electronic Dissertation Authors Lee, Janice Christine Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 02/10/2021 09:45:45 Link to Item http://hdl.handle.net/10150/193782 ON THE PREVALENCE OF STARBURSTS IN DWARF GALAXIES by Janice Christine Lee A dissertation submitted to the faculty of the DEPARTMENT OF ASTRONOMY in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY in the Graduate College of THE UNIVERSITY OF ARIZONA 2006 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Janice Christine Lee entitled On the Prevalence of Starbursts in Dwarf Galaxies and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy _______________________________________________________________________ Date: September 5, 2006 Robert Kennicutt _______________________________________________________________________ Date: September 5, 2006 Deidre Hunter _______________________________________________________________________ Date: September 5, 2006 Romeel Dave _______________________________________________________________________ Date: September 5, 2006 Xiaohui Fan Final approval and acceptance of this dissertation is contingent upon the candidate’s submission of the final copies of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement. ________________________________________________ Date: September 5, 2006 Dissertation Director: Robert Kennicutt 3 STATEMENT BY AUTHOR This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the Univer- sity Library to be made available to borrowers under rules of the Library. Brief quotations from this dissertation are allowable without special permis- sion, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. SIGNED: Janice Christine Lee 4 ACKNOWLEDGMENTS I am extremely grateful for the strong scientific network that has supported my intellectual and professional development as an astronomer, and it is a sincere pleasure to acknowledge the folks that have been at its core. First, special thanks are in order for my advisor Rob Kennicutt. Like any par- ent with high expectations for his children, Rob would never, ever allow me to short-change myself in terms of my career aspirations, and by example he has impressed upon me the critical importance of unyielding tenacity and contin- ual growth. Rob’s sage scientific guidance and support has been important in helping me to complete this thesis and to also lay the groundwork for ambitious future endeavors. I would also like to thank my H« survey teammates who have labored to create the dataset on which this thesis is based. This includes Rob, who has led the project, data analyst extraordinaire Sanae Akiyama, who also manages the broader H« flux database, Jose Funes (Vatican Observatory) and Shoko Sakai (UCLA). Sanae, Jose and Shoko have also given me much advice and encourage- ment for which I am grateful. Two others who have been absolutely integral to helping me survive in our intensely competitive field are John Salzer (Wesleyan) and Liese van Zee (Indi- ana). Salzer and the Wesleyan Astronomy Department (to whom I also owe my gratitude) opened the doors for me to a life in academic research when there were few other options for a person who had already left college on an alternate career path. van Zee took me under her wing early in my grad career when I was con- vinced my dissertation should focus on observationally constraining the inner profiles of dark matter haloes. For many years, both of these incredibly devoted teachers have not only been expert sounding boards for my ideas and questions on the nature of star formation in dwarf galaxies, but have also been generous dispensers of advice, comfort and friendship. I also warmly thank my peers (both former and current grads and postdocs) at Steward for their camaraderie and for creating the supportive, fun and fer- tile scientific environment that I have grown in. Those who must be especially noted include Joannah Hinz, Chien Peng, Christian Drouet D’Aubigny, academic siblings John Moustakas and Moire Prescott, officemate Iva Momcheva, Christy Tremonti, Rose Finn, Casey Meakin, Marianne Vestergard, Audra Baleisis, Cathy Petry and all the members of the recently established Women’s Science Forum. Finally, fruitful discussions with committee member D. Hunter (Lowell), D. Garnett, D. Zaritsky, A. Zabludoff, former advisor C. Impey, A. Dolphin, D. Mc- Carthy, J. Harris, M. Mac Low (AMNH), E. Skillman (Minnesota), S. Oey (Michi- gan), C. Martin (UCSB), and J. Gallagher (Wisconsin) are acknowledged. M. Haynes (Cornell) is thanked for providing access to the GALPHOT package and the Arecibo General Catalog of HI in local galaxies. 5 DEDICATION They say that it takes a village to raise a child, and this must especially be true when mom is off writing a thesis. I thus dedicate this work to the small village of devoted family and friends who have helped me care for my children while I have worked countless days and nights trying to figure out what in the Universe is going on in these very complicated dwarf galaxies. For my family — for my husband Ted, whose passions and life goals parallel my own — at the roots, it is our true and equal partnership in marriage and par- enthood that makes it possible for us to simultaneously fulfill our commitments to both our children and our chosen vocations. For my mom Evylin, my dad Ben, my sisters Jenny and Nin, and my brother Jun. For the teachers and staff and the Satori School. And for the good Lord, who has abundantly provided for and watched over all of us. I am extremely thankful for all of you – your precious ef- forts have been essential in enabling me to finally reach this milestone. Kobe and Kylie, of course, are very lucky to have you too, and it is my utmost hope that the examples that we set for them now will inspire and propel them to assiduously seek out their dreams in the future and live their lives to the very, very fullest. 6 TABLE OF CONTENTS LIST OF FIGURES ................................ 9 LIST OF TABLES ................................. 11 ABSTRACT .................................... 12 CHAPTERS: 1INTRODUCTION 14 1.1 The Significance of Starbursts in Dwarf Galaxies ........... 14 1.2 Methods for Constraining the Prevalence of Bursts . .... 15 1.3 Our Current Understanding of the Evolutionary Status of Dwarf Irregular Galaxies . ...................... 18 1.4 Overview of the Thesis . ...................... 21 2OBSERVATIONS OF THE CURRENT STAR FORMATION IN A COMPLETE SAMPLE OF DWARF GALAXIES 25 2.1 Introduction . ............................. 25 2.2 The 11HUGS Sample . ...................... 27 2.2.1 The Motivations for, and Challenges in Assembling a Volume-Limited Sample in the Local Neighborhood . .... 27 2.2.2 Construction of the Sample . ............... 30 2.2.3 A Catalog of Star-Forming Galaxies within 11 Mpc . .... 37 2.3 11HUGS: H« Imaging . ...................... 52 2.3.1 Observations . ...................... 52 2.3.2 Image Processing and Continuum Subtraction . .... 54 2.3.3 Astrometry . ...................... 55 2.3.4 Aperture Photometry ...................... 56 2.3.5 Absolute Flux Calibration . ............... 57 2.3.6 Integrated Flux and EW Error Analysis . ........... 58 2.3.7 Literature Comparison of Integrated Fluxes and EW .... 62 2.3.8 The 11HUGS Integrated H« Flux and EW Catalog . .... 68 3BASIC PROPERTIES OF THE 11HUGS SAMPLE 85 3.1 Selection Properties . ...................... 85 3.2 Completeness . ............................. 85 Ì 3.2.1 The Rauzy Completeness Statistic . ........... 86 3.2.2 Luminosity and Mass Functions Comparisons . .... 89 3.2.3 Comparison with Local Volume Galaxies found in HIPASS . 91 3.3 Non-detections . ............................. 92 7 TABLE OF CONTENTS — CONTINUED 4GLOBAL STAR FORMATION PROPERTIES OF GALAXIES IN THE 11 MPC VOLUME:GENERAL OBSERVATIONAL PATTERNS 100 4.1 ABSTRACT . .............................100 4.2 The H« EW as a Relative Star Formation Indicator . ....101 Å Î ÑÜ 4.3 The Local Galaxy Sequence in the -EW and -EW Planes . 102 4.3.1 Sources of Data . ......................103 4.3.2 Qualitative Features . ......................104 4.3.3 Quantitative Features ......................107 4.3.4 Physical Underpinnings of the Observed Sequence . ....110 5DWARF GALAXY STARBURST STATISTICS 122 5.1 ABSTRACT . .............................122 5.2 Adopted Definitions . ......................122