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Gravitation and Multimessenger Astrophysics Imre Bartos Gravitation and Multimessenger Astrophysics by Imre Bartos Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Graduate School of Arts and Sciences COLUMBIA UNIVERSITY 2012 c 2012 Imre Bartos All Rights Reserved Abstract Gravitation and Multimessenger Astrophysics by Imre Bartos Gravitational waves originate from the most violent cosmic events, which are often hidden from traditional means of observation. Starting with the first direct observation of gravita- tional waves in the coming years, astronomy will become richer with a new messenger that can help unravel many of the yet unanswered questions on various cosmic phenomena. The ongoing construction of advanced gravitational wave observatories requires disruptive innovations in many aspects of detector technology in order to achieve the sensitivity that lets us reach cosmic events. We present the development of a component of this technology, the Advanced LIGO Optical Timing Distribution System. This technology aids the detection of relativistic phenomena through ensuring that time, at least for the observatories, is absolute. Gravitational waves will be used to look into the depth of cosmic events and understand the engines behind the observed phenomena. As an example, we examine some of the plausible engines behind the creation of gamma ray bursts. We anticipate that, by reaching through shrouding blastwaves, efficiently discovering off-axis events, and observing the central engine at work, gravitational wave detectors will soon transform the study of gamma ray bursts. We discuss how the detection of gravitational waves could revolutionize our understanding of the progenitors of gamma ray bursts, as well as related phenomena such as the properties of neutron stars. One of the most intriguing directions in utilizing gravitational waves is their combination with other cosmic messengers such as photons or neutrinos. We discuss the strategies and ongoing efforts in this direction. Further, we present the first observational constraints on joint sources of gravitational waves and high energy neutrinos, the latter of which is created in relativistic plasma outflows, e.g., in gamma ray burst progenitors. High energy neutrinos may be created inside a relativistic outflow burrowing its way out of a massive star from the star's collapsed core. We demonstrate how the detection of high en- ergy neutrinos can be used to extract important information about the supernova/gamma-ray burst progenitor structure. We show that, under favorable conditions, even a few neutrinos are sufficient to probe the progenitor structure, opening up new possibilities for the first detections, as well for progenitor population studies. We present the science reach and method of an ongoing search for common sources of gravitational waves and high energy neutrinos using the initial LIGO/Virgo detectors and the partially completed IceCube detector. We also present results on the sensitivity of the search. We argue that such searches will open the window onto source populations whose electromagnetic emission is hardly detectable. Contents 1 Introduction1 1.1 Gravitational Radiation..............................4 1.1.1 Ripples in spacetime............................5 1.1.2 Interaction of gravitational waves with matter..............7 1.1.3 Generation of gravitational waves.....................8 1.1.4 Indirect evidence for the existence of gravitational waves........9 1.2 Astrophysical Sources of Gravitational Waves..................9 1.2.1 Gravitational wave emission processes in GRBs............. 10 1.2.2 GRB astrophysics with gravitational waves............... 23 1.3 Gravitational Wave Detectors........................... 28 1.3.1 Gravitational wave interferometry.................... 29 1.3.2 Noise sources in earth-based interferometers............... 33 1.3.3 Laser Interferometer Gravitational-wave Observatory.......... 37 1.4 Multimessenger Sources of Gravitational Waves and High Energy Neutrinos. 40 1.4.1 High-Energy Neutrinos........................... 40 1.4.2 Common sources of gravitational waves and high energy neutrinos.. 45 1.5 Searching for Gravitational Waves........................ 47 1.5.1 Gravitational wave search strategies................... 47 1.5.2 Electromagnetic counterpart....................... 52 1.5.3 Neutrino counterpart............................ 53 1.5.4 Host galaxies................................ 56 2 The Advanced LIGO Timing System 59 2.1 Timing in Gravitational-wave Astrophysics................... 60 i 2.2 System Architecture................................ 62 2.2.1 Master module............................... 64 2.2.2 Fan-Out module.............................. 65 2.2.3 Slave module................................ 65 2.2.4 DuoTone generation............................ 66 2.2.5 Operation Diagram............................. 66 2.2.6 Selection of 1PPS input.......................... 69 2.2.7 Master Phase-locked Loop Configuration................. 69 2.2.8 Fan-Out/Slave Phase-locked Loop Configuration............ 70 2.2.9 Fiber Delay Determination........................ 70 2.2.10 Structure of the Diagnostic Output Data: Overview.......... 72 2.2.11 Diagnostics................................. 75 2.3 Performance and Tests............................... 76 2.4 Summary...................................... 78 3 Observational Constraints on Joint Sources of Gravitational Waves and High Energy Neutrinos 79 3.1 Bounding the time delay between gravitational waves and high energy neutri- nos from GRBs................................... 79 3.1.1 Gamma-ray Emission........................... 81 3.1.2 High-energy Gamma-ray Emission.................... 82 3.1.3 Gravitational-wave Emission....................... 84 3.1.4 High-energy Neutrino Production..................... 85 3.1.5 GRB Precursors.............................. 87 3.1.6 Summary.................................. 88 3.2 Observational constraints on multimessenger source population........ 91 3.2.1 Upper limits from neutrino observations................. 91 3.2.2 Upper limits from gravitational-wave observations........... 94 3.2.3 Joint GW+HEN population upper limits................ 95 3.2.4 Discussion.................................. 99 ii 4 Probing the Structure of Jet Driven Core-collapse Supernova and Long Gamma Ray Burst Progenitors with High Energy Neutrinos 100 4.1 CCSN and GRB Progenitors........................... 101 4.2 Calculations and Results.............................. 103 4.2.1 Optical Depth for High-Energy Neutrinos................ 103 4.2.2 Temporal Structure of Jets........................ 108 4.2.3 Energy-dependent Emission Onset Time................. 110 4.2.4 Dependence on source parameters.................... 111 4.3 Interpretation of Energy and Time Structure of Neutrino Emission...... 111 4.3.1 Strong-signal limit............................. 111 4.3.2 Weak-signal limit.............................. 112 4.4 Conclusions..................................... 115 5 Search for Common Sources of Gravitational Waves and High Energy Neu- trinos 117 5.1 Data......................................... 118 5.1.1 Gravitational-wave Data.......................... 118 5.1.2 High-energy Neutrino Data........................ 119 5.1.3 Neutrino Clustering............................ 121 5.1.4 Astrophysical Source Distribution - the Galaxy Catalog........ 122 5.2 Joint GW+HEN Analysis............................. 124 5.2.1 Coincidence Time Window........................ 125 5.2.2 Joint GW+HEN Significance....................... 127 5.2.3 Background Trigger Generation...................... 128 5.2.4 Individual Detection............................ 130 5.2.5 Statistical Detection of Multiple Sources................. 131 5.2.6 Simulation of Astrophysical Signals.................... 133 5.2.7 Population Estimation........................... 133 5.3 Science Reach.................................... 134 5.3.1 Estimated Sensitivity........................... 139 5.4 Closed box results................................. 141 Conclusion & Outlook 145 iii A Glossary 167 iv List of Figures 1-1 Schematic diagram of the evolution of compact binary coalescences. While the inspiral phase is observable for a few seconds, the merger and ringdown phases last only a few milliseconds. If a hypermassive NS is formed during the merger, it can survive potentially for up to a second before collapsing into a BH. 11 1-2 Schematic spectrum of effective amplitude heff for compact binary coales- cences. During the inspiral phase up to ≈ 1 kHz and the early-merger phase up to fcut ∼ 3 kHz, the system retains its binary-like structure and heff scales as f −1=6. If a BH is present or is promptly formed, matter quickly falls in the BH, losing angular momentum through emitting GWs around a peak fre- quency fpeak ∼ 5 − 6 kHz. If a HMNS is formed from a NS-NS binary, it will radiate GWs through its quasiperiodic rotation at fqpd ∼ 2 − 3 kHz. As the HMNS loses substantial angular momentum before collapsing into a BH, its GW emission at fpeak will be smaller. After matter falls into the BH, the BH rings down, emitting GWs at ≈ 6:5 − 7 kHz with exponentially decaying amplitude. (Inspired by Fig. 2 of Ref. [1]).................... 13 1-3 Schematic diagram of GW emission scenarios of collapsars........... 17 1-4 Schematic diagram of the effect of a passing gravitational wave on a Michelson interferometer (courtesy of Giacomo Ciani; with modifications)......... 30 1-5 Schematic diagram of LIGO (courtesy of Yoichi Aso).............
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