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Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and wAite photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Bell & Howell Information and Learning 300 North Zeeb Road, Ann Arbor. Ml 48106-1346 USA 800-521-0600 UMT NOTE TO USERS This reproduction Is the best copy available. UMI UNIVERSITY OF OKLAHOMA GRADUATE COLLEGE THE DIRECT ANALYSIS OF SPECTRA OF TYPE LA SUPERNOVAE A DISSERTATION SUBMITTED TO THE GRADUATE FACULTY in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY By Kazuhito Hatano Norman, Oklahoma 2000 UMI Number. 9975802 UMI UMI Microform9975802 Copyright 2000 by Bell & Howell Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. Bell & Howell Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 © Copyright by Kazuhito Hatano 2000 All Rights Reserved THE DIRECT ANALYSIS OF SPECTRA OF TYPE lA SUPERNOVAE A DISSERTATION APPROVED FOR THE DEPARTMENT OF PHYSICS AND ASTRONOMY BY David Branch (Chair) Edward Baron William Romanishin towski Kelvin Droegemeier Acknowledgments I wish to thank David Branch for his unlimited support, kindness, understanding, and patience for my works. Without his advisements, this thesis would not have been completed. I would also like to thank Eddie Baron for many discussions and answering my technical questions. I would also like to thank Bill Romanishin, Ron Kantowski, and Kelvin Droegemeier for serving as a committee member and offering useful advisements. I would like to thank the people in the supernova group, Adana Fisher, Peter Nugent, Dean Elichardson, Eric Lentz, Darrin Casebeer, and Jennifer Deaton for their suggestions and discussions. I also wish to thank Nick and Penny Nicholas, my family, and my friends for kind supports. Finally, I wish to thank Peter Gamavich, Alex Filippenko, and Yulei Qiu for providing me lots of observed spectra and figures. IV Table of Contents Introduction 1 1.1 Classification of S N e ................................................................................... 1 1.2 Progenitor of SNe ......................................................................................... 3 1.3 Goal of This Dissertation ............................................................................. 4 Ion Signatures in Supernova Spectra 6 2.1 INTRODUCTION ..................................................................................... 7 2.2 LINE OPTICAL D EPTH S......................................................................... 8 2.2.1 Calculations ....................................................................................... 8 2.2.2 Hydrogen-rich .................................................................................... 12 2.2.3 Helium-Rich .................................................................................... 16 2.2.4 Carbon/Oxygen-Rich .................................................................... 20 2.2.5 C arbon-burned ................................................................................. 22 2.2.6 O xygen-burned................................................................................. 22 2.2.7 Nickel-decay ....................................................................................... 26 2.3 SYNTHETIC SPECTRA ......................................................................... 28 2.4 Additional discussions ............................................................................... 29 3 Ion Signatures in Supernova Spectra II: Ultraviolet (UV) and In­ frared (IR) 40 On the High-Velocity Ejecta of the Type la Supernova 1994D 58 4.1 Introduction ................................................................................................... 59 4.2 Previous Studies of SN 1994D S p e c tr a .................................................. 59 4.3 Spectrum Synthesis Procedure .................................................................. 60 4.4 R esults............................................................................................................ 61 4.4.1 Twelve Days Before M axim um ....................................................... 61 4.4.2 Eight and Two Days Before M aximum ...................................... 63 4.4.3 Evolution of the Ca II H&K F eature .......................................... 67 4.5 D iscussion ........................ 69 4.6 Conclusion ...................................................................................................... 71 5 On the Spectrum of the Peculiar Type la Supernova 1997br and the Nature of SN 1991T-like Events 74 5.1 Introduction ..................................................................................................... 75 5.2 Procedure and Results ................................................................................. 76 5.2.1 Pre-m axim um.................................................................................... 77 5.2.2 P ost-m axim um ................................................................................. 80 5.3 Discussion ........................................................................................................ 84 5.4 Conclusion ........................................................................................................ 91 Spectral Analysis of the Sub—Luminous Type la SNe 92 6.1 Sub-Luminous Type la S N e ...................................................................... 93 6.1.1 SN 1991bg......................................................................................... 93 6.1.2 SN 1999by......................................................................................... 94 6.1.3 S u m m a ry......................................................................................... 101 6.2 Analysis of the 580 nm Feature .................................................................. 103 6.2.1 The 580 nm Feature and the Depth R a tio .................................... 103 6.2.2 Ti II Lines ......................................................................................... 109 Spectral Analysis of Other Type la SNe 115 7.1 Early Time Spectra ......................................................................................... 115 7.1.1 SN 1986G ..................................................................................... 116 7.1.2 SN 1 9 9 2 A ..................................................................................... 117 7.1.3 SN 1 9 8 9 B ..................................................................................... 120 7.1.4 SN 1 9 9 4 D ..................................................................................... 121 7.1.5 SN 1998aq ..................................................................................... 124 7.1.6 SN 1999aa..................................................................................... 126 7.1.7 SN 1 9 9 0 N ..................................................................................... 130 7.1.8 SN 1998bu ..................................................................................... 132 7.1.9 D iscussion ......................................................................................... 137 7.2 High-Velocity S u p em o v ae ............................................................................ 139 7.2.1 SN 1 9 8 4 A ..................................................................................... 139 7.2.2 SN 1997bq ..................................................................................... 141 7.2.3 SN 19 9 9 cl..................................................................................... 141 7.2.4 D iscussion .......................................................................................... 144 8 On the Spectroscopic Diversity of Type la Supernovae 150 8.1 Introduction ................................................................................................... 151 8.2 D a t a ................................................................................................................ 152 8.3 Results ............................................................................................................. 153 VI 8.3.1 R(Si II) versus uio(Si I I ) ................................................................ 153 8.3.2 Pre-maximum spectra ...................................................................