The Landscape of Relativistic Stellar Explosions

ISBN-13: 9783031153662 / Angielski / Twarda / 2022 / 307 str.

Anna Y. Q. Ho

Opis

This thesis reports the discovery of relativistic stellar explosions outside of the gamma ray band, using optical time domain surveys. It is well known that some massive stars end their lives with the formation of a compact object (a neutron star or black hole) that launches a relativistic jet detectable from earth as a burst of gamma rays. It has long been suspected, however, that gamma ray bursts are only the tip of the iceberg in a broad landscape of relativistic explosions, and so the results presented in this thesis represent a major breakthrough. Highlights of this thesis include: characterization of the first major new class of relativistic explosions in a decade; the discovery of abrupt end-of-life mass-loss in a surprisingly diverse range of stars; and the routine discovery of afterglow emission and several events that may represent baryonically dirty jets or jets viewed slightly off axis. These discoveries necessitated the solution of difficult technical challenges such as the identification of rare and fleeting “needles” in a vast haystack of time-varying phenomena in the night sky, and responding to discoveries within hours to obtain data across the electromagnetic spectrum from X-rays to radio wavelengths. 

Spis treści

TABLE OF CONTENTS

Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii

Published Content and Contributions . . . . . . . . . . . . . . . . . . . . . . ix

Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

List of Illustrations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii

List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxiv

Chapter I: Introduction and Summary . . . . . . . . . . . . . . . . . . . . . 1

1.1 Landscape Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Summary of Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Chapter II: ZTF20aajnksq (AT 2020blt): A Fast Optical Transient at I 2•9

With No Detected Gamma-Ray Burst Counterpart . . . . . . . . . . . . . 13

2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

2.3 Comparison to GRB Afterglows . . . . . . . . . . . . . . . . . . . . 22

2.4 Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . 32

Chapter III: iPTF Archival Search for Fast Optical Transients . . . . . . . . . 35

3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3.2 Data and Candidate Selection . . . . . . . . . . . . . . . . . . . . . 38

3.3 Properties of the iPTF M-dwarf Flares . . . . . . . . . . . . . . . . 40

3.4 Rate of Relativistic Fast Optical Transients in iPTF . . . . . . . . . . 45

3.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.6 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Chapter IV: SN 2020bvc: a Broad-lined Type Ic Supernova with a Doublepeaked

Optical Light Curve and a Luminous X-ray and Radio Counterpart 52

4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

4.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

4.3 Light Curve Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 67

4.4 Spectroscopic Properties . . . . . . . . . . . . . . . . . . . . . . . . 69

4.5 Modeling the Light Curve . . . . . . . . . . . . . . . . . . . . . . . 74

4.6 Modeling the Fast Ejecta . . . . . . . . . . . . . . . . . . . . . . . . 77

4.7 Early ZTF Light Curves of Nearby Ic-BL SNe . . . . . . . . . . . . 83

4.8 Summary and Discussion . . . . . . . . . . . . . . . . . . . . . . . 85

4.9 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Chapter V: The Broad-lined Ic Supernova ZTF18aaqjovh (SN 2018bvw): An

Optically Discovered Engine-driven Supernova Candidate with Luminous

Radio Emission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

5.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

xi

5.3 Analysis and Discussion . . . . . . . . . . . . . . . . . . . . . . . . 119

5.4 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . 125

Chapter VI: Evidence for Late-stage Eruptive Mass Loss in the Progenitor to

SN 2018gep, a Broad-lined Ic Supernova: Pre-explosion Emission and a

Rapidly Rising Luminous Transient . . . . . . . . . . . . . . . . . . . . 128

6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

6.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

6.3 Basic Properties of the Explosion and its Host Galaxy . . . . . . . . 146

6.4 Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

6.5 Comparison to Unclassified Rapidly Evolving Transients at High

Redshift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

6.6 Summary and Future Work . . . . . . . . . . . . . . . . . . . . . . 171

6.7 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Chapter VII: AT2018cow: A Luminous Millimeter Transient . . . . . . . . . 195

7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

7.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

7.3 Basic Properties of the Shock . . . . . . . . . . . . . . . . . . . . . 206

7.4 Implications of Shock Properties . . . . . . . . . . . . . . . . . . . 218

7.5 Origin of the X-ray Emission and Emergence of a Compact Source . 226

7.6 Conclusions and Outlook . . . . . . . . . . . . . . . . . . . . . . . 230

7.7 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

Chapter VIII: TheKoala: AFast Blue Optical Transient with Luminous Radio

Emission from a Starburst Dwarf Galaxy at I = 0•27 . . . . . . . . . . . 238

8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239

8.2 Discovery and Basic Analysis . . . . . . . . . . . . . . . . . . . . . 243

8.3 Comparison With Extragalactic Explosions . . . . . . . . . . . . . . 252

8.4 Interpretation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258

8.5 Rate Estimate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

8.6 Prospects for Detecting X-ray Emission . . . . . . . . . . . . . . . . 269

8.7 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . 269

8.8 Appendix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

Chapter IX: Other Contributions . . . . . . . . . . . . . . . . . . . . . . . . 276

9.1 ZTF19abvizsw: ACosmological AfterglowWithNo Detected Gammaray

Burst . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

9.2 How Much CSM is Sufficient to Choke a Jet? . . . . . . . . . . . . . 276

9.3 Radio Observations of Ic-BL SNe Discovered by ZTF . . . . . . . . 277

Chapter X: The Future . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 280

O autorze

Anna Y. Q. Ho is an assistant professor of astronomy at Cornell University.