Western University Scholarship@Western Electronic Thesis and Dissertation Repository 12-7-2018 1:30 PM Multiwavelength, Machine Learning, and Parallax Studies of X-ray Binaries in Three Local Group Galaxies Robin Arnason The University of Western Ontario Supervisor Barmby, Pauline The University of Western Ontario Graduate Program in Astronomy A thesis submitted in partial fulfillment of the equirr ements for the degree in Doctor of Philosophy © Robin Arnason 2018 Follow this and additional works at: https://ir.lib.uwo.ca/etd Part of the External Galaxies Commons Recommended Citation Arnason, Robin, "Multiwavelength, Machine Learning, and Parallax Studies of X-ray Binaries in Three Local Group Galaxies" (2018). Electronic Thesis and Dissertation Repository. 5931. https://ir.lib.uwo.ca/etd/5931 This Dissertation/Thesis is brought to you for free and open access by Scholarship@Western. It has been accepted for inclusion in Electronic Thesis and Dissertation Repository by an authorized administrator of Scholarship@Western. For more information, please contact [email protected]. Abstract X-ray binary stars are rare systems consisting of a black hole or neutron star and a main- sequence companion star. They are useful probes of galaxy properties and interesting labora- tories for extreme physical conditions. In this thesis, I investigated the X-ray binary population of three galaxies in the Local Group. The Sculptor Dwarf Spheroidal Galaxy offers the chance to study a primordial low-mass X-ray binary (LMXB) population in an isolated, low-metallicity environment. Combining X- ray, optical, and infrared observations, I have studied nine previously identified and discovered four additional LMXB candidates in this galaxy. Of these candidates, all but one are either background galaxies or foreground stars, meaning that Sculptor is presently effectively devoid of bright LMXBs. If Sculptor is able to retain primordial LMXBs at a similar rate to globular clusters, it is likely that bright XRBs in globular clusters observed in the present day were dynamically formed. The Andromeda Galaxy has the largest catalogue of Chandra-studied X-ray sources of any nearby galaxy. I have used this population to test a proof-of-concept method for identifying X-ray binary candidates using machine learning algorithms trained on known sources. After testing a variety of commonly used algorithms, I find that the best-performing random forest algorithm can identify X-ray binary candidates with ∼ 85% accuracy. I have identified 16 new strong X-ray binary candidates and find that 4 sources classified as X-ray binaries by this method coincide with star clusters identified by the Panchromatic Hubble Andromeda Treasury project. The Milky Way’s X-ray binary population is the easiest to study but the most challenging for which to accurately measure distance. I have crossmatched Galactic X-ray binary catalogs to the second data release of the Gaia mission, finding candidate counterparts for 86 Galactic X-ray binaries. Distances to Gaia candidate counterparts are systematically smaller than those measured using Type I X-ray bursts, suggesting that these bursts do not consistently reach the Eddington limit. High-mass X-ray binaries are correlated with the Galaxy’s spiral arms and low-mass X-ray binaries are anti-correlated with the Galaxy’s spiral arms at a low level of significance. Keywords: binaries: X-ray; Galaxies: Local Group; Galaxies, individual: Sculptor Dwarf Spheroidal, M31, Milky Way; stars: black holes, neutron; X-rays: bursts – Galaxy: structure; techniques: parallaxes, methods: statistical, observational i Co-Authorship Statement All research is the result of collaboration; this thesis is no exception. Each of the three projects presented in this thesis was led by me, and I performed the analysis. I have benefited greatly from guidance, suggestions, and assistance in interpretation from my co-authors: my supervi- sor Dr. Pauline Barmby, Dr. Arash Bahramian, Dr. Steve Zepf, Dr. Thomas Maccarone, Dr. Neven Vulic, Hadi Papei, and Dr. Mark Gorski. In Chapter 2, Dr. Maccarone and Dr. Zepf were the PIs of the original observations that made the project possible. They also provided assistance in interpretation. Dr. Barmby performed the reduction of the Spitzer data - I performed my analysis on the completed Spitzer catalogues. Dr. Bahramian took the Chandra observations that I reduced and ran them in ACISEXTRACT. I performed the analysis and interpretation of the Chandra photometry and spectroscopy that are the products of ACISEXTRACT. Dr. Barmby and Dr. Bahramian also assisted in interpretation of the results. This paper is submitted to Monthly Notices of the Royal Astronomical Society. In Chapter 3, Dr. Vulic created the Chandra catalogs used in the study. I joined the individual catalogs for each field, and performed all of the analysis. Dr. Vulic and Dr. Barmby provided guidance both on the catalogue itself, as well as interpretation of the results. This paper will be submitted shortly. In Chapter 4, Dr. Barmby and Mr. Papei performed the work of investigating the method used in the literature to measure distance to each X-ray binary in our matched sample. I cross- matched the catalogues to Gaia, though Mr. Papei performed the query to the Bailer-Jones catalogue to obtain the Gaia distance to each object. I constructed the simulation and per- formed the analysis. Dr. Barmby, Dr. Gorski, and Mr. Papei all provided guidance on the interpretation of results. This paper will be submitted shortly. ii Epigraph “The popular stereotype of the researcher is that of a skeptic and a pessimist. Nothing could be further from the truth! Scientists must be optimists at heart, in order to block out the incessant chorus of those who say ‘It cannot be done.’ ” - Sid Meier’s Alpha Centauri (1999) iii Dedication For Mom, Dad, Holly, Ba, and all the birds. iv Acknowledgements This thesis has, like many, been a mix of exciting discovery and keyboard-breaking frustration. No one knows this better than my supervisor, Dr. Pauline Barmby. For the last four years you’ve been my mentor, my ally, my collaborator, and my friend. You taught me by example that being a good scientist isn’t just a matter of doing good research – we also have a duty to make a positive impact on our community, whether on campus or elsewhere. I could not have had a better supervisor. The direction of my thesis has benefited immensely from guidance from my Advisory Committee members. Thanks to Dr. Jan Cami and Dr. Giovanni Fanchini, who gave me useful research/career advice and struck a balance between pushing me forward and letting me work out the details. Special thanks also to the collaborators who I have had the privilege of working with over the course of this degree: Dr. Arash Bahramian, Dr. Tom Maccarone, Dr. Steve Zepf, Dr. Neven Vulic, Dr. Mark Gorski, and Hadi Papei. Without your guidance and assistance my thesis would not have gotten off the ground. Thanks to the wonderful staff and faculty at Western P&A who have been there to help in matters academic and bureaucratic: Clara Buma, Brian Davis, Phin Perquin, Henry Leparskas, Dr. Sarah Gallagher, Dr. Martin Houde, Dr. Els Peeters, Dr. Stan Metchev, Dr. Paul Wiegert, Dr. Silvia Mittler, and Dr. Andy Pon. Good friends are rarer than X-ray binaries, and I’ve been blessed to have many here at Western. Keegan, Moh, Dan, Megan, Amanda, Kendra, Isabelle, Hadi, Ghazal, Sina, Sahar, Laura, Aycha, Shannon, Amgad, Jeff, Cameron, and Ellie. Thanks for all the great times and for your support, I couldn’t have done it without you. I also owe my success to my friends at home and abroad who have been there in spirit as I worked my way through this degree. Reggie, Sarah, Arash, Andrei, Ana, Stephen P., Abbie, Caitie, Kaitlyn, Stephen B., Megan, Mitch, Ryley, Curt, Karl, Ed, Kabir, Nathan, Kris, Kaylie, Dave, Amy, and Pearl. Thanks always to my family, who has helped and supported me since the very beginning. Mom, you taught me the value of effective writing and communication and you’re the best secret baking advice-giver I could ask for. Dad, you helped ignite my sense of wonder and curiosity in the mysteries of the universe. Holly, you’ve been my forever friend since my first moment in this world. Ba, you’ve always believed that I’ve had the smarts to do whatever I wanted, ever since I was very small. Thanks for the love and the support – I love you. v Contents Abstract i Co-Authorship Statement ii Epigraph iii Dedication iv Acknowledgements v List of Figures ix List of Tables xi 1 Introduction 1 1.1 Compact Stellar Remnants . 1 1.2 X-ray Binary Formation . 6 1.3 Galaxies and the Local Group . 11 1.4 X-ray Binaries in the Local Group . 17 2 Multiwavelength survey of Sculptor Dwarf X-ray Sources 32 2.1 Introduction . 32 2.1.1 XRB Production . 32 2.1.2 XRB Populations in Dwarf Galaxies . 34 2.1.3 Sculptor Dwarf Spheroidal Galaxy . 35 2.2 Data . 35 2.2.1 Chandra Data Reduction . 35 2.2.2 Gemini Imaging Data Reduction . 36 2.2.3 Gemini Spectroscopic Data . 38 2.2.4 Spitzer Data . 38 2.2.5 Matching . 39 2.3 Analysis . 39 2.3.1 SD X-1 . 40 2.3.2 SD X-2 . 41 2.3.3 SD X-3 . 45 2.3.4 SD X-4 . 45 2.3.5 SD X-5 . 45 vi 2.3.6 SD X-6 . 48 2.3.7 SD X-7 . 48 2.3.8 SD X-8 . 48 2.3.9 SD X-9 . 49 2.3.10 SD X-10 . 49 2.3.11 SD X-11 . 49 2.3.12 SD X-12 .