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Copyright by Robert Michael Quimby 2006 The Dissertation Committee for Robert Michael Quimby certifies that this is the approved version of the following dissertation: The Texas Supernova Search Committee: J. Craig Wheeler, Supervisor Peter H¨oflich Carl Akerlof Gary Hill Pawan Kumar Edward L. Robinson The Texas Supernova Search by Robert Michael Quimby, A.B., M.A. DISSERTATION Presented to the Faculty of the Graduate School of The University of Texas at Austin in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY THE UNIVERSITY OF TEXAS AT AUSTIN December 2006 Acknowledgments I would like to thank J. Craig Wheeler, Pawan Kumar, Gary Hill, Peter H¨oflich, Rob Robinson and Christopher Gerardy for their support and advice that led to the realization of this project and greatly improved its quality. Carl Akerlof, Don Smith, and Eli Rykoff labored to install and maintain the ROTSE-IIIb telescope with help from David Doss, making this project possi- ble. Finally, I thank Greg Aldering, Saul Perlmutter, Robert Knop, Michael Wood-Vasey, and the Supernova Cosmology Project for lending me their image subtraction code and assisting me with its installation. iv The Texas Supernova Search Publication No. Robert Michael Quimby, Ph.D. The University of Texas at Austin, 2006 Supervisor: J. Craig Wheeler Supernovae (SNe) are popular tools to explore the cosmological expan- sion of the Universe owing to their bright peak magnitudes and reasonably high rates; however, even the relatively homogeneous Type Ia supernovae are not intrinsically perfect standard candles. Their absolute peak brightness must be established by corrections that have been largely empirical. Hundreds of SNe are now found every year, shrinking the statistical errors in the cosmolog- ical parameters, but most of these distant discoveries do little to further the physical understanding of SNe, which could illuminate unknown systematics. The Texas Supernova Search was not designed to discover the most SNe nor the most distant SNe, but it was instead created to amass a small collection of well-observed nearby SNe with detailed, multi-epoch spectral observations beginning at the earliest possible phases. For the past two years, I have pointed ROTSE-IIIb's 1.85 X 1.85 degree field of view at nearby galaxy clusters and v searched thousands of galaxies, covering hundreds of square degrees on the sky, for supernovae. With ToO time on the neighboring 9.2m Hobby-Eberly Telescope, the search has captured SNe spectra at some of the earliest phases ever. In this dissertation I describe the Texas Supernova Search and present the 30 supernovae, 11 novae, and 6 dwarf novae discovered in the first two years of the program. vi Table of Contents Acknowledgments iv Abstract v List of Tables xi List of Figures xii Chapter 1. Introduction 1 Chapter 2. Early-Time Observations of the GRB 050319 Opti- cal Transient 6 2.1 Introduction . 7 2.2 Observations . 8 2.3 Analysis . 9 2.4 Results . 11 2.5 Discussion . 18 Chapter 3. SN 2005cg: Explosion Physics and Circumstellar In- teraction of a Normal Type Ia Supernova in a Low- Luminosity Host 23 3.1 Introduction . 24 3.2 Observations . 26 3.3 The Si IIline profiles . 30 3.4 Evidence for CSM Interaction . 33 3.5 Host Galaxy and Progenitor Constraints . 34 3.6 SN 2005cg in Context With Other SNe Ia . 38 3.7 Discussion and Conclusions . 39 vii Chapter 4. The Texas Supernova Search 43 4.1 Search Fields . 44 4.2 Search Pipeline . 53 4.2.1 Imaging . 53 4.2.2 Data Flow . 54 4.2.3 Reference Templates . 55 4.2.4 Image Subtraction . 56 4.2.5 Candidate Filtering . 58 4.2.6 Web-Based Scanning . 61 4.2.7 Final Checks . 64 4.3 Observing Log . 64 4.4 ROTSE-III Light Curves . 74 4.5 HET Spectra . 76 Chapter 5. TSS Discoveries 78 5.1 Supernovae . 78 5.1.1 SN 2004gk . 82 5.1.2 SN 2004gu . 83 5.1.3 SN 2004gy . 84 5.1.4 SN 2005ap . 85 5.1.5 SN 2005ay . 86 5.1.6 SN 2005az . 87 5.1.7 SN 2005bg . 88 5.1.8 SN 2005ck . 89 5.1.9 SN 2005cr . 90 5.1.10 SN 2005hf . 91 5.1.11 SN 2005hj . 92 5.1.12 SN 2005ir . 93 5.1.13 SN 2005la . 93 5.1.14 SN 2005nb . 94 5.1.15 SN 2006X . 95 5.1.16 SN 2006an . 96 viii 5.1.17 SN 2006bj . 97 5.1.18 SN 2006bp . 98 5.1.19 SN 2006cg . 99 5.1.20 SN 2006cj . 99 5.1.21 SN 2006ct . 100 5.1.22 SN 2006cy . 101 5.1.23 SN 2006da . 102 5.1.24 SN 2006db . 103 5.1.25 SN 2006eb . 103 5.1.26 SN 2006em . 104 5.1.27 SN 2006gt . 105 5.1.28 SN 2006gy . 105 5.1.29 SN 2006hx . 106 5.1.30 SN 2006je . 107 5.2 Extragalactic Novae . 138 5.3 Galactic Dwarf Novae . 152 5.4 Other Variable Stars . 159 Chapter 6. SN 2005hj: Evidence for Two Classes of Normal- Bright SNe Ia and Implications for Cosmology 165 6.1 Introduction . 166 6.2 Observations . 170 6.2.1 Spectral Characteristics of SN 2005hj . 176 6.3 Physical Constraints from Explosion Models . 182 6.4 Discussion and Conclusions . 190 Chapter 7. SN 2006bp: Probing the Shock Breakout of a Type II Supernova 196 7.1 Photometry . 196 7.1.1 ROTSE-III Light Curve . 204 7.2 Spectroscopy . 206 7.3 Discussion . 210 Appendices 223 ix Appendix A. RPHOT: A Photometry Package for ROTSE-III Data 224 A.1 Running RPHOT . 225 A.1.1 The RPHOT Photometry Console . 227 A.1.2 Selecting The Target and Reference Stars . 228 A.1.3 Aperture Photometry . 230 A.1.4 PSF-fit Photometry . 232 A.1.5 Neighbor Subtraction . 232 A.1.6 Photometry Calibration . 233 A.1.7 Light Curve Binning . 234 A.2 Photometry Checks . 235 A.3 Analysis Tools . 236 A.4 Input and Output . 236 A.4.1 Making Figures and Tables Within RPHOT . 237 A.4.2 Other Command Line Options . 237 Appendix B. The GRBlog Database and Web Interface 238 B.1 The GRB Coordinates Network . 238 B.2 Motivation for GRBlog . 239 B.3 Extraction of GCN Circular Data . 239 B.4 GRBlog Interface . 240 B.4.1 Message View . 240 B.4.2 Burst View . 241 B.4.3 Table View . 243 B.4.4 Data View . 243 B.5 GRBlog Search Form . 246 Bibliography 250 Vita 264 x List of Tables 2.1 ROTSE-IIIb Observations of GRB 050319 . 13 4.1 TSS Search Fields . 50 4.1 TSS Search Fields . 51 4.1 TSS Search Fields . 52 4.2 TSS Observing Log . 69 4.2 TSS Observing Log . 70 4.2 TSS Observing Log . 71 5.1 Supernovae Discovered by the TSS . 80 5.2 Extragalactic Novae Discovered by the TSS . 139 5.3 Galactic Dwarf Novae Discovered by the TSS . 152 5.4 Variable Stars Discovered by the TSS . 160 5.4 Variable Stars Discovered by the TSS . 161 5.4 Variable Stars Discovered by the TSS . 162 5.4 Variable Stars Discovered by the TSS . 163 5.4 Variable Stars Discovered by the TSS . 164 6.1 Observing Log for HET Spectra of SN 2005hj . 173 7.1 ROTSE-III Observations of SN 2006bp . 200 7.1 ROTSE-III Observations of SN 2006bp . 201 7.1 ROTSE-III Observations of SN 2006bp . 202 7.1 ROTSE-III Observations of SN 2006bp . 203 7.2 Observing Log for HET Spectra of SN 2006bp . 207 A.1 RPHOT modes . 228 xi List of Figures 2.1 ROTSE-III and RAPTOR light curve for the GRB 050319 op- tical transient for t0 = ttrigger0. The line gives the best fit single power-law to the combined data set, α = −0:854. The verti- cal shaded band marks the last, FRED-like peak in the γ-ray light curve and the arrow marks the first break in the XRT light curve. RAPTOR data have been shifted by 0.21 mag as described in the text. 14 2.2 ROTSE-III and RAPTOR light curve for the GRB 050319 opti- cal transient for t0 = ttrigger1. The line gives the best smoothly broken power-law fit to the joint data set with α1 = −0:36, α2 = −0:88, and tb = 418 s. The smoothness parameter was fixed at s = 20. The arrow marks the first break in the XRT light curve. 16 3.1 ROTSE-IIIc unfiltered light curve of SN 2005cg (magnitudes calibrated against the Sloan r-band). The curve is the fitted R-band template from Knop et al. (2003) dilated in time by (1+z)=s where s.
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