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GRAVITATIONAL SIGNATURE of CORE-COLLAPSE SUPERNOVA RESULTS of CHIMERA SIMULATIONS by Konstantin Yakunin

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GRAVITATIONAL SIGNATURE of CORE-COLLAPSE SUPERNOVA RESULTS of CHIMERA SIMULATIONS by Konstantin Yakunin GRAVITATIONAL SIGNATURE OF CORE-COLLAPSE SUPERNOVA RESULTS OF CHIMERA SIMULATIONS by Konstantin Yakunin A Dissertation Submitted to the Faculty of The Charles E. Schmidt College of Science in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Florida Atlantic University Boca Raton, FL August 2011 Copyright by Konstantin Yakunin 2011 ii GRAVITATIONAL SIGNATURE OF CORE-COLLAPSE SUPERNOVA RESULTS OF CHIMERA SIMULATIONS by Konstantin Yakunin This dissertation was prepared under the direction of the candidate's dissertation advisor, Dr. Pedro Marronetti, Department of Physics, and has been approved by the members of his supervisory committee. It was submitted to the faculty of the Charles E. Schmidt College of Science and was accepted in partial fulfillment of the requirements for the degree of Doctor of Philosophy. SUPERVISORY COMMITTEE: Pedro Marronetti, Ph.D. Dissertation Advisor Stephen W. Bruenn, Ph.D. Dissertation Co-Advisor Warner A. Miller, Ph.D. William Kalies, Ph.D. Warner A. Miller, Ph.D. Chair, Department of Physics Gary W. Perry, Ph.D. Dean, The Charles E. Schmidt College of Science Barry T. Rosson, Ph.D. Date Dean, Graduate College iii ACKNOWLEDGEMENTS I am deeply thankful to my thesis advisor, Dr. Pedro Marronetti who guided my studies during the PhD program. My achievements wouldn't have been possible without his support and understanding. His sage advices, insightful criticisms, and patient encouragement aided the writing of this thesis in innumerable ways. I would also express my gratitude to my co-advisor Dr. Steven W. Bruenn whose steadfast support of this project was greatly needed and deeply appreciated. I deeply thank Dr. Shin Yoshida for the smooth and enjoyable collaboration on the supernova code and gravitational wave code. I am grateful to Dr. Antony Mezzacappa and all present and past members of CHIMERA collaborations for giving me the possibility to do this thesis. I am grateful to my committee members Dr. Warner Miller, Dr. William Kalies for providing me with valuable feedback, and I greatly appreciate financial support for this work by National Science Foundation (grant NSF-PHYS-0855315). I thank my teachers, Elena Evgenievna Kazakova, Dr. Valery Petrovich Beskachko, Dr. Christopher Beetle, Dr. Shen Li Qiu, and Dr. Sam Faulkner for sharing their knowledge with me. I thank my friend Cyndee Finkel for her constant altruistic support and for proof-reading. Lastly, I offer my regards and blessings to everybody at Department of Physics who supported me in any respect during these years. iv ABSTRACT Author: Konstantin Yakunin Title: Gravitational Signature of Core-Collapse Supernova Results of CHIMERA Simulations Institution: Florida Atlantic University Dissertation Advisor: Dr. Pedro Marronetti Degree: Doctor of Philosophy Year: 2011 Core-collapse supernovae (CCSN) are among the most energetic explosions in the universe, liberating ∼ 1053 erg of gravitational binding energy of the stellar core. Most of this energy (∼ 99%) is emitted in neutrinos and only 1% is released as electromagnetic radiation in the visible spectrum. Energy radiated in the form of gravitational waves (GWs) is about five orders smaller. Nevertheless, this energy corresponds to a very strong GW signal and, because of this CCSN are considered as one of the prime sources of gravitational waves for interferometric detectors. Gravita- tional waves can give us access to the electromagnetically hidden compact inner core of supernovae. They will provide valuable information about the angular momentum distribution and the baryonic equation of state, both of which are uncertain. Fur- thermore, they might even help to constrain theoretically predicted SN mechanisms. Detection of GW signals and analysis of the observations will require realistic signal predictions from the non-parameterized relativistic numerical simulations of CCSN. This dissertation presents the gravitational wave signature of core-collapse v supernovae. Previous studies have considered either parametric models or non- exploding models of CCSN. This work presents complete waveforms, through the explosion phase, based on first-principles models for the first time. We performed 2D simulations of CCSN using the CHIMERA code for 12, 15, and 25M non-rotating progenitors. CHIMERA incorporates most of the criteria for realistic core-collapse modeling, such as multi-frequency neutrino transport coupled with relativistic hydrodynamics, effective GR potential, nuclear reaction network, and an industry-standard equation of state. Based on the results of our simulations, I produced the most realistic gravitational waveforms including all postbounce phases of core-collapse supernovae: the prompt convection, the stationary accretion shock instability, and the corresponding explosion. Additionally, the tracer particles applied in the analysis of the GW signal reveal the origin of low-frequency component in the prompt part of gravitational waveform. Analysis of detectability of the GW signature from a Galactic event shows that the signal is within the band-pass of current and future GW observatories such as AdvLIGO, advanced Virgo, and LCGT. vi DEDICATION This thesis is dedicated to my parents, Nikolay Alekseevich Yakunin and Liudmila Vladimirovna Yakunina CONTENTS List of Figures ................................ x 1 Introduction .................................. 1 2 Supernovae .................................. 4 2.1 Classification of Supernovae.......................4 2.2 Core-Collapse supernovae rates.....................7 2.3 The mechanism of core collapse supernova...............9 3 Gravitational Waves ............................. 20 3.1 General Relativity............................ 21 3.2 Linearized Theory............................. 21 3.3 Wave solution in vacuum......................... 22 3.4 Polarization of Gravitational Waves................... 23 3.5 Gravitational Radiation in the Weak-Field Slow-Motion Limit.... 25 3.6 Gravitational Wave Astronomy..................... 25 3.6.1 Estimation of the detectability of gravitational signals from CCSN 25 3.6.2 Gravitational waves detectors.................. 26 4 CHIMERA Code ............................... 33 4.1 Hydrodynamics in CHIMERA...................... 34 4.2 Gravity in CHIMERA.......................... 38 4.2.1 Derivation of effective GR potential............... 40 vii 4.2.2 Implementation.......................... 41 4.2.3 Tests of the effective GR potential................ 42 4.3 Neutrino Transport............................ 45 4.4 Nuclear Reaction Network........................ 46 4.5 Equations of State............................ 49 4.6 Tracer particle method.......................... 51 5 Gravitational Wave Analysis ....................... 53 5.1 Mass quadrupole of gravitational wave................. 53 5.2 Gravitational waves produced by anisotropic neutrino emission.... 55 5.2.1 Definition of angles........................ 57 5.3 Direction dependent neutrino luminosity dL=dΩ............ 60 5.4 Numerical implementation........................ 61 5.4.1 Computation of N20 ....................... 61 5.5 Verification tests............................. 61 5.5.1 Oscillating ring around a central mass............. 61 5.5.2 Rotating triaxial ellipsoid.................... 64 6 Results ..................................... 66 6.1 Gravitational Wave Emission by Aspherical Mass Motions...... 66 6.1.1 Prompt signal........................... 68 6.1.2 Quiescent stage.......................... 72 6.1.3 Strong signal........................... 72 6.1.4 The \tail"part........................... 74 6.2 Gravitational Wave Emission by Anisotropic Neutrino Radiation... 84 7 Conclusions and Future Work ....................... 90 viii A Tensor spherical harmonics flm ...................... 95 A.1 Explicit form of Wlm and Xlm ...................... 95 A.2 Tensor spherical harmonics........................ 96 B Transverse traceless part of \directional"tensor . 97 C Analytical tests of the GW code. ..................... 99 C.1 Rotating ellipsoid test.......................... 99 C.2 Oscillating Ring Test........................... 104 Bibliography ................................. 107 ix LIST OF FIGURES 2.1 The current classification scheme of supernovae. Type Ia SNe are as- sociated with the thermonuclear explosion of accreting white dwarfs. Other SN types are associated with the core collapse of massive stars. Some type Ib/c and IIn SNe with explosion energies E > 1052 erg are often called hypernovae..........................5 2.2 The spectra of the main SN types at maximum, three weeks, and one year after maximum. The representative spectra are those of SN1996X for type Ia, of SN1994I (left and center) and SN1997B (right) for type Ic, of SN1999dn (left and center) and SN1990I (right) for type Ib, and of SN1987A for type II. At late times (especially in the case of the type Ic SN1997B) the contamination from the host galaxy is evident as an underlying continuum plus unresolved emission lines. In all figures of this paper the spectra have been transformed to the parent galaxy rest frame....................................6 2.3 The distribution of number of the detected CCSNe events with the distance during the initial LIGO epoch (2002 - 2010)..........9 2.4 Remnants of massive single stars as a function of initial metalicity and initial mass. In the regions above the thick green line (for the higher initial metalicity), the hydrogen envelope is stripped during its evolution due to the active mass loss processes. The dashed
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