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Galactic Building Blocks: Searching for Dwarf Galaxies Near and Far Andrew Lipnicky [email protected]

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Rochester Institute of Technology RIT Scholar Works Theses Thesis/Dissertation Collections 7-2017 Galactic Building Blocks: Searching for Dwarf Galaxies Near and Far Andrew Lipnicky [email protected] Follow this and additional works at: http://scholarworks.rit.edu/theses Recommended Citation Lipnicky, Andrew, "Galactic Building Blocks: Searching for Dwarf Galaxies Near and Far" (2017). Thesis. Rochester Institute of Technology. Accessed from This Dissertation is brought to you for free and open access by the Thesis/Dissertation Collections at RIT Scholar Works. It has been accepted for inclusion in Theses by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. R I T · · Galactic Building Blocks: Searching for Dwarf Galaxies Near and Far Andrew Lipnicky A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Astrophysical Sciences and Technology in the College of Science, School of Physics and Astronomy Rochester Institute of Technology © A. Lipnicky July, 2017 Rochester Institute of Technology Ph.D. Dissertation Galactic Building Blocks: Searching for Dwarf Galaxies Near and Far Author: Advisor: Andrew Lipnicky Dr. Sukanya Chakrabarti A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Astrophysical Sciences and Technology in the College of Science, School of Physics and Astronomy Approved by Dr.AndrewRobinson Date Director, Astrophysical Sciences and Technology Certificate of Approval Astrophysical Sciences and Technology R I T College of Science · · Rochester, NY, USA The Ph.D. Dissertation of Andrew Lipnicky has been approved by the undersigned members of the dissertation committee as satisfactory for the degree of Doctor of Philosophy in Astrophysical Sciences and Technology. Dr. Margaret Bailey, Committee Chair Date Dr. Sukanya Chakrabarti, Dissertation Advisor Date Dr. Eric Blackman Date Dr. Jeyhan Kartaltepe Date For my father. ACKNOWLEDGEMENTS It takes a village to raise a child. Likewise, it takes a collaboration to make great science and the work presented in this Dissertation could not have been done without the help of many, many people. Firstly, I would like to thank my family, especially my mother and late father, for always supporting me and helping me through the hard times I have faced along the way. I am also indebted to Camille Erickson, for supporting me through all the late nights, crazy ramblings, and always lending me her ear, I am so thankful. My good friend, Marcus Freeman, also deserves my gratitude for all the wonderful, long emails of support and so much more. I would also like to recognize all my friends and officemates for helpful discussions and laughs, especially Triana Almeyda, Kevin Cooke, Davide Lena, Dmitry Vorobiev, and Dan Wysocki. I would be remiss if I did not also thank my Artisan family of Scottsville for all the morning laughs and advice. Of course, I would also like thank my advisor, Sukanya Chakrabarti, for her support and understanding. Mel Wright, William Cotton, and Jay Lockman also deserve my thanks for all their help with the radio data reduction. Nidia Morrell deserves special recognition for stepping in to perform my observations in Chile when I simultaneously got an ear, throat, sinus, eye, and chest infection and had to go to the hospital to recover. Michael Richmond also deservers special recognition for all the help he gave me with the optical observations I performed, the many letters of support he wrote, and for always being able to explain my research to me more easily than I could. Finally, I would like to thank my program director, Andy Robinson, for all the guidance and support he o↵ered me. I would like to thank the Shea Garrison-Kimmel and the ELVIS collaboration, Barbara Can- tinella and the GASS collaboration, and Juerg Diemand and Via Lactea collaboration for making their data publicly available and easily accessible. Some of the data presented in this dissertation 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. Parts of this dissertation made use of data from the Sloan Digital Sky Survey. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org. My work has been supported by the National Radio Astronomy Observatory under the Student Observing Support program project GBT 16B-285 and from National Science Foundation grant number 1517488. i DECLARATION I, ANDREW LIPNICKY (“the Author”), declare that no part of this dissertation is substan- tially the same as any that has been submitted for a degree or diploma at the Rochester Institute of Technology or any other University. I further declare that this work is my own. Those who have contributed scientific or other collaborative insights are fully credited in this Dissertation, and all prior work upon which this Dissertation builds is cited appropriately throughout the text. This Dissertation was successfully defended in Rochester, NY, USA on June 21, 2017. A Chapter of this Dissertation has previously been published by the Author in a peer-reviewed paper appearing in the Monthly Notices of the Royal Astronomical Society (MNRAS): • Chapter 2 is based on paper Lipnicky & Chakrabarti (2017), entitled Is the vast polar structure of dwarf galaxies a serious problem for ⇤ cold dark matter?, (2017, MNRAS, 468, 1671), co-authored with Sukanya Chakrabarti (the Dissertation advisor). A Chapter of this Dissertation will be submitted for peer-review and publication: • Chapter 3 is based on a paper entitled Scaling Relations for Neutral Hydrogen Studies of Spiral Galaxies: Relating Density Structure to Passing Satellites (in preparation), co-authored with Sukanya Chakrabarti (the Dissertation advisor), and collaborator Phillip Chang. A Chapter of this Dissertation has been submitted for peer-review and publication to appear in the Monthly Notices of the Royal Astronomical Society: • Chapter 5 is based on a paper entitled The First Detection of Neutral Hydrogen in Emission in a Strong Spiral Lens (MNRAS, submitted), co-authored with Sukanya Chakrabarti (the Dissertation advisor), and collaborators Melvyn C. H. Wright, Leo Blitz, Carl Heiles, William Cotton, David Frayer, Roger Blandford, Yiping Shu, and Adam S. Bolton. ii LIST OF PUBLISHED WORK 1. The First Detection of Neutral Hydrogen in Emission in a Strong Spiral Lens Andrew Lipnicky, Sukanya Chakrabarti, Melvyn C. H. Wright, Leo Blitz, Carl Heiles, William Cotton, David Frayer, Roger Blandford, Yiping Shu, and Adam S. Bolton, 2017, MNRAS, submitted 2. Galactoseismology: Discovery of a cluster of receding, variable halo stars Sukanya Chakrabarti, Rodolfo Angeloni, Kenneth Freeman, Benjamin Sargent, Joshua D. Simon, Piotr Konorski, Wolfgang Gieren, Branimir Sesar, Andrew Lipnicky, Leo Blitz, Gibor Basri, Massimo Marengo, William Vacca, Puragra Guhathakurta, Alice Quillen, and Philip Chang, 2017, ApJL, accepted 3. Is the vast polar structure of dwarf galaxies a serious problem for ⇤ cold dark matter? Andrew Lipnicky and Sukanya Chakrabarti, 2017, MNRAS, 468, 1671 iii ABSTRACT The prevailing model of structure formation that describes how matter is distributed through- out the Universe is known as the ⇤cold dark matter paradigm. A key component of this paradigm is dark matter, which has so far gone undetected in laboratory experiments but is inferred from a wide variety of astrophysical observations. Although the cold dark matter paradigm is extremely successful on large scales, there are significant di↵erences between what computer simulations pre- dict and what we observe on galaxy scales. The purpose of the work presented in this Dissertation is to address some of the issues surrounding the current structure formation paradigm and further develop some tools for investigating small scale structure. An issue that has caused recent contro- versy is known as the Planes of Dwarf Galaxies problem which describes the curious alignment of the Milky Way’s dwarf galaxies into a thin planar structure. We have investigated this structure through time by integrating their orbits using the latest proper motion data as well as compared the distribution with current cosmological simulations and found no significant di↵erence between the Milky Way distribution and simulations. Through analysis of observations of the disturbances in the extended neutral hydrogen disks of spiral galaxies, one can characterize dark matter substructure and the dark matter halo of a host galaxy. This process is called Tidal Analysis. Using a simple test particle code to model satellite interactions with a gas disk, we have developed a scaling relation to relate the observed density response of the disk to the mass and pericenter of a satellite. With this relation, observers can now immediately infer the recent interaction history of a spiral galaxy from neutral hydrogen studies. Changing gears to observational studies of small scale structure, we report observations of Cepheid variables in a putative dwarf galaxy located along the line of sight of the galactic plane that was first predicted through the use of Tidal Analysis. Observations are still ongoing; however, preliminary results indicate that the Cepheids are part of structure that is moving independently of the Milky Way. Finally, in an e↵ort to use Tidal Analysis on other galaxies to constrain substructure, we have begun a 21-cm radio observing campaign of a set of spiral galaxies at redshift z 0.1 to obtain ⇠ their total mass in neutral hydrogen. This unique set of galaxies also act as strong gravitational lenses, thus allowing us to use both Tidal Analysis and gravitational lensing together for the first time.
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  • METALLICITY DISTRIBUTION FUNCTIONS of FOUR LOCAL GROUP DWARF GALAXIES* Teresa L

    METALLICITY DISTRIBUTION FUNCTIONS of FOUR LOCAL GROUP DWARF GALAXIES* Teresa L

    The Astronomical Journal, 149:198 (14pp), 2015 June doi:10.1088/0004-6256/149/6/198 © 2015. The American Astronomical Society. All rights reserved. METALLICITY DISTRIBUTION FUNCTIONS OF FOUR LOCAL GROUP DWARF GALAXIES* Teresa L. Ross1, Jon Holtzman1, Abhijit Saha2, and Barbara J. Anthony-Twarog3 1 Department of Astronomy, New Mexico State University, P.O. Box 30001, MSC 4500, Las Cruces, NM 88003-8001, USA; [email protected], [email protected] 2 NOAO, 950 Cherry Avenue, Tucson, AZ 85726-6732, USA 3 Department of Physics and Astronomy, University of Kansas, Lawrence, KS 66045-7582, USA; [email protected] Received 2015 January 26; accepted 2015 April 16; published 2015 May 27 ABSTRACT We present stellar metallicities in Leo I, Leo II, IC 1613, and Phoenix dwarf galaxies derived from medium (F390M) and broad (F555W, F814W) band photometry using the Wide Field Camera 3 instrument on board the Hubble Space Telescope. We measured metallicity distribution functions (MDFs) in two ways, (1) matching stars to isochrones in color–color diagrams and (2) solving for the best linear combination of synthetic populations to match the observed color–color diagram. The synthetic technique reduces the effect of photometric scatter and produces MDFs 30%–50% narrower than the MDFs produced from individually matched stars. We fit the synthetic and individual MDFs to analytical chemical evolution models (CEMs) to quantify the enrichment and the effect of gas flows within the galaxies. Additionally, we measure stellar metallicity gradients in Leo I and II. For IC 1613 and Phoenix our data do not have the radial extent to confirm a metallicity gradient for either galaxy.