Radio Pulsars in Binary Systems Ren´ePaul Breton Department of Physics McGill University Montr´eal,Qu´ebec Canada December 2008 A Thesis submitted to McGill University in partial fulfillment of the requirements of the degree of Doctor of Philosophy c Ren´eP. Breton, 2008 Pour mon p`ere,ma m`ereet mon fr`ere. Votre support depuis toujours est un cadeau inestimable. Contents Abstract xi Resum´ e´ xii Acknowledgments xiii Contributions of Authors xvi 1 Introduction 1 1.1 In a Nutshell... 1 1.2 Historical Background . 4 1.2.1 The Great Discovery . 4 1.2.2 Theoretical Precursor Work . 11 1.2.3 Parallel Discoveries . 13 1.3 Thesis Outline . 14 2 Neutron Stars and Pulsars 17 2.1 Neutron Stars: An Overview . 17 2.1.1 Internal Structure and Equation of State . 20 2.1.2 Magnetic Field . 24 2.2 Pulsars: An Overview . 25 2.2.1 Rotation-Powered Pulsars . 26 2.2.2 Non-Rotation-Powered Pulsars . 35 2.3 Measurements of Pulsar Properties . 37 2.3.1 Mass . 37 2.3.2 Radius . 43 2.3.3 Magnetic Field . 44 2.4 Radio Telescopes . 47 2.5 Pulsar Timing . 51 2.5.1 Extrinsic Timing Components . 54 2.5.2 Intrinsic Timing Components . 58 2.5.3 Binary Pulsar Timing . 60 2.6 Binary Pulsars . 64 2.6.1 Binary Evolution . 66 2.6.2 Binary Radio Pulsar Population . 73 2.6.3 Other Pulsar Binaries . 80 2.7 Binary Pulsars as Benchmarks for Gravity Theories . 86 2.7.1 “Classical” Tests of Gravity . 86 2.7.2 Other Tests of Gravity . 89 2.8 The Double Pulsar . 89 v vi Contents 3 The Unusual Binary Pulsar PSR J1744−3922 92 3.1 Introduction . 93 3.2 Pulsed Radio Flux Variability . 95 3.2.1 Data and Procedure . 97 3.2.2 Radio-frequency-dependent Variability . 99 3.2.3 Orbital Correlation Analysis . 106 3.2.4 Accretion and mass loss limits . 110 3.3 Infrared Observations . 112 3.4 Binary Pulsar Evolution . 117 3.5 Discussion . 124 3.5.1 Recycled High Magnetic Field Pulsar Channel . 124 3.5.2 UCXB Evolutionary Track Channel . 126 3.5.3 AIC Channel . 128 3.6 Conclusions . 130 4 The Eclipses of the Double Pulsar 131 4.1 Introduction . 132 4.1.1 Unique Eclipses . 132 4.1.2 Spin-Orbit Coupling . 133 4.2 Observations and Data Reduction . 134 4.3 Eclipse Phenomenology . 136 4.3.1 Modulations . 138 4.3.2 Duration . 150 4.4 Eclipse Modeling . 154 4.4.1 The Lyutikov and Thompson Model . 154 4.4.2 Technical Definitions . 156 4.4.3 Relativistic Spin Precession . 161 4.5 Eclipse Model Fitting . 162 4.5.1 MCMC Analysis . 162 4.5.2 MCMC Results . 165 4.5.3 Grid Search . 165 4.5.4 Grid Search Results . 171 4.5.5 Analysis of Systematics . 171 4.6 New Strong-Field Regime Test from Relativistic Spin Precession . 177 4.6.1 Future Perspectives . 179 4.7 Lessons from the Geometry . 181 4.7.1 Degenerate Solutions . 181 4.7.2 Spin Direction and Direction of Precession . 183 4.7.3 Orbital Inclination . 185 4.7.4 Emission Geometry of Pulsar B . 186 Contents vii 5 Latitudinal Aberration in the Double Pulsar 192 5.1 Introduction . 193 5.2 Theoretical Background . 194 5.3 Observations and Data Reduction . 200 5.4 Simplified Model . 201 5.5 Bayesian Analysis . 204 5.5.1 Constant Model, M0 ....................... 205 5.5.2 Constant Model + Noise, M0s .................. 206 5.5.3 Rafikov and Lai Model + Noise, M2s . 207 5.5.4 Model Selection . 208 5.5.5 Upper Limit on the Amplitude Parameter C . 209 5.6 Discussion . 213 5.6.1 Single-Cone Emission . 213 5.6.2 Two-Cone Emission . 218 5.7 Conclusion . 222 6 Conclusion 223 A Remarks About the Notion of Strong-Field Regime228 A Definition of Variables Used in Chapter 5 230 Bibliography 232 List of Figures 1.1 Artistic representation of a pulsar . 2 1.2 Satellite view of the Mullard Radio Astronomy Observatory . 6 1.3 Discovery observation of the first pulsar . 9 2.1 Cross-section view of a typical neutron star . 23 2.2 The P − P˙ diagram . 30 2.3 Schematic view of a pulsar’s emission regions . 33 2.4 Magnetar’s magnetic field lines twisting . 38 2.5 Neutron star mass measurements . 40 2.6 Spectral fit of a white dwarf’s atmosphere . 42 2.7 X-ray spectrum of a quiescent LMXB . 45 2.8 The Crab’s pulsar wind nebula . 48 2.9 The Green Bank Telescope . 49 2.10 The Parkes Telescopse . 50 2.11 A superheterodyne receiver . 52 2.12 Typical output of pulsar data . 55 2.13 Pulsar signal dedisperion . 57 2.14 Representation of an idealized glitch . 61 2.15 Schematic view of a Keplerian orbit . 62 2.16 Effect of the Shapiro delay on the double pulsar . 65 2.17 Distribution of spin periods . 67 2.18 The Roche lobe equipotential surface . 69 2.19 Radius evolution of a 5 M star . 70 2.20 Evolution-type phase space . 72 2.21 The binary pulsar population . 74 2.22 Distribution of spin periods: binaries, GC and GC binaries . 82 2.23 Distribution of spin periods: binaries and GC . 83 2.24 Distribution of spin periods: binaries and GC binaries . 84 2.25 Orbital period decay of the Hulse-Taylor pulsar . 88 3.1 Sample folded intensity profiles of PSR J1744−3922 . 96 3.2 Sample radio pulsed flux density time series for PSR J1744−3922 . 100 3.3 Distribution of the measured pulsed flux density of PSR J1744−3922 105 3.4 Orbital variability of the pulsed flux of PSR J1744−3922 . 108 3.5 Near-infrared counterpart of PSR J1744−3922’s companion . 114 3.6 White dwarf cooling tracks . 116 3.7 Orbital period versus companion mass for binary pulsars . 119 viii List of Figures ix 3.8 Magnetic field strength versus spin period for binary pulsars . 122 3.9 Spin period versus orbital period for binary pulsars . 123 4.1 Pulsar B’s pulse profile evolution . 137 4.2 Eclipse profile of pulsar A with pulsar B’s time of arrival . 140 4.3 Eclipse profile of pulsar A observed on MJD 52997 . 142 4.4 Power density spectrum of pulsar A’s eclipse profile observed on MJD 52997143 4.5 Eclipse light curve and power density spectrum of pulsar A at 325 MHz 144 4.6 Eclipse light curve and power density spectrum of pulsar A at 427 MHz 145 4.7 Eclipse light curve and power density spectrum of pulsar A at 1400 MHz146 4.8 Eclipse light curve and power density spectrum of pulsar A at 1950 MHz147 4.9 Eclipse light curve and power density spectrum of pulsar A at 2200 MHz148 4.10 Dynamic power spectrum of the double pulsar eclipse . 149 4.11 Folded eclipse profile . 151 4.12 Eclipse duration as a function of observed radio frequency . 155 4.13 Schematic view of the double pulsar system at the eclipse . 158 4.14 Joint a posteriori probability of α and φ . 166 4.15 Joint a posteriori probability of α and θ . 167 4.16 Joint a posteriori probability of α and z0 . 168 4.17 Long-term evolution of the eclipse profile at 820 MHz . 170 4.18 Marginalized a posteriori probability distributions for the eclipse mod- eling . ..