Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1989 Using Tilted-Ring Models and Numerical Hydrodynamics to Study the Structure, Kinematics and Dynamics of HI Disks in Galaxies. Dimitris Michael Christodoulou Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Christodoulou, Dimitris Michael, "Using Tilted-Ring Models and Numerical Hydrodynamics to Study the Structure, Kinematics and Dynamics of HI Disks in Galaxies." (1989). LSU Historical Dissertations and Theses. 4769. https://digitalcommons.lsu.edu/gradschool_disstheses/4769 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS The most advanced technology has been used to photo- ’ graph and reproduce this manuscript from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are re­ produced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. These are also available as one exposure on a standard 35mm slide or as a 11 " x 23" black and white photographic print for an additional charge. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Beil & HoweM Information Com pany 300 North Zeeb Road .Arm Arbor Ml 48106 184b USA 313/614/00 800 5210600 Order Number 901725S Using tilted-ring models and numerical hydrodynamics to study the structure, kinematics a^d dynamics of HI disks in galaxies Christodoulou, Dimitris Michael, Ph.D. The Louisiana State University and Agricultural and Mechanical Col., 1989 U-M-I 300 N. Zeeb Rd. Ann Arbor, MI 48106 USING TILTED-RING MODELS AND NUMERICAL HYDRODYNAMICS TO STUDY THE STRUCTURE, KINEMATICS AND DYNAMICS OF HI DISKS IN GALAXIES A Dissertation Submitted to the Graduate Faculty of the Louisiana State I lnversity and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Physics and Astronomy by Dimitris Michael Christodoulou B.S., University of Thessaloniki, Greece. 19S4 August 1989 A C K N O W L ED OE M I M S The hist few years at LSE have been a delight. My work lias moved ahead smoothly m an ideal environment Many people and several resources have heen responsible. The Vi >1 k reported in this dispel t at ii >n has hern sponsored, in part, by \S F through the giants AS I So 01S-12 and ASJ Si 01 ,">03 to ,1. E. Tohhne and. 111 part, hy the Louisiana State I_ nive] sity. lint this is a page primarily devoted to ]>eople. First. I would like to thank my a (hi-or. Dr. Joel E. d oh line, for his continuous help and guidance and for all the things lie taught me. Indeed. only those rvho have worked with him can really appreciate the difference. Second. 1 would like to express my appreciation to I)rs. Ganesh Chan miipiin. Arlo Landolt. Charles Perry. Detlev km -ter. and John Drilling for Teaching me Astronomy, Tim'd. I have to thank Monika Lee and fha tensia \ aides for assisting me m computations rind Linda Gauthier for typing many manuscripts, including this one. Jeff Anderson's work on video animat ion and movie making is also greatly appreciat ed. Finally. I should acknowledge the fun I haic had all those nights at the com­ puter room and the nearby coffee shop. G<>n/alo kuster. Harold Williams. Han Chen. Bing Y 11. Saied Andalih, and Ramon Lopez Pena are definitely guilty for sharing the fun. In addition. I am obliged to Harold for many stimulating discussions before and after he left LSI . ii TABLE OI CONTENTS page Acknnwledgi‘liients ........................................................................................................................ ii Table of Content' ........................................................................................................................ iii List of In’ >!< - ... .......................................................................................................................... \ List < if I- igui < s ............................. vi Abst met ......................................................................................................................................... viii 1 Int roductiou ............................................................................................................................. 1 1.1 Kmemntical versus Dynamical Modeling ............................................................. 2 1.2 Historical Out line of Ilelated Work ....................................................................... 4 1.2 Summary of this Wot k ................................................................................................. S '1 Ki:.< ]..•: ’,< ;•! NI<ol*•]i:.r. ......................................................................................................... 13 2 .1 Edgi1 on Spirals .............................................................................................................. 13 2.2 Barred Spirals ................................................................................................................ 17 2.3 HI Disks m Ellipticals ............... IS 2.4 Permission to Publish Observations ................................................................... 20 3 Dynamical Modeling ..... ........................................................................................ 20 3.1 Introduction ................................ 30 3.2 Dynamical Equations and Initial M odels ............................................. 35 3.3 Settling Time-Scales and Inflow ............................................................................ 37 3.-4 Model Evolutions .......................................................................................................... 42 a ) /„ — 0° .......................................................................................................................... 42 b) Low and moderate inclinations 43 c) High inclinations and polar rings ..................................................................... 44 d) Strongly distorted halos ...................................................................................... 47 in pn^e i i Development of dynamical twists ........................ 40 3.5 Linear Behavior of the PP Instability ..................................................................... 50 4 Summary of Conclusions ................................................................................. 85 Epilogue ....................... SO References ....................................................................................................................................... 00 Appendix A .................................. 05 Appendix If .................................................................... 101 Appendix ( 1 1 2 Cui'i'ieulmn Vita ........................................ 2S2 IV LIST OF TABLES page Table 2.1 Warping A twisting angles for C'en A .................................................. 24 Table 3.1 Estimated settling t ime-seales ...................... 53 Table 3.2 Linear growth rates (^.7 1 and ]>attern S]>eeds (j,’/f ) of the PP instability ........................................................ 54 \ LIST OF FIGURES page Figure 2.1 Isodensity maps of NGC 0007 from the standard tilted-ring model (top) and from a spiral densiry field showing an illusionary warp (bottom) .................................. 25 Figure 2.2 Isovelocity maps of NGC 572S from the actual observation [Seliommrr el ill- 1 f)SS] (top) and from the tilted-ring model ............................................... 20 2.5 Isi neloci (y maps of NGC 51 2^ ( Cen A) from the actual observation [Bland et ah 10S7J ( top) and from the model (m iddle) and the model s isodensity map (bottom) ......................................................................... 27 F igm f 2.4 Isovelocity maps of NGC 4275 fi oin the actual observation [Knapp 19S2] (top) and from t he m<xlel (bot tuni) ............................... 2S F IgtUl * 3.1 (a) 3 D isodensity diagrams duiing the evolution of the extended ring (tn„ — 4.2 j. initially ])laced at an inclination of t,, — 1 0 ° from the equatorial plane of a spheroidal potential