SYNTHETIC OBSERVATIONS USING A ROBUST END-TO-END RADIATIVE TRANSFER MODELING PIPELINE A Dissertation Presented to The Academic Faculty By Kirk Stuart Simeon Barrow In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the School of Physics Georgia Institute of Technology May 2018 Copyright c Kirk Stuart Simeon Barrow 2018 SYNTHETIC OBSERVATIONS USING A ROBUST END-TO-END RADIATIVE TRANSFER MODELING PIPELINE Approved by: Dr. John Wise, Advisor Dr. Tamara Bogdonovic School of Physics School of Physics Georgia Institute of Technology Georgia Institute of Technology Dr. David Ballantyne Dr. Marcus Holzinger School of Physics School of Aerospace Engineering Georgia Institute of Technology Georgia Institute of Technology Dr. Pablo Laguna, Chair Date Approved: March 27, 2018 School of Physics Georgia Institute of Technology Acknowledgments I would first like to thank my thesis advisor Dr. John Wise for his mentorship, his patience, and his insight these long six years from undergrad through to my defense. It has been a harrowing journey and I certainly could not have done it without him. I would also like to thank the Georgia Tech School of Physics and the Center for Relativistic Astrophysics for facilitating an excellent academic program and a continuous stream of invited speakers. I would of course also like to thank the school for taking a chance on me and supporting me financially as a research assistant and a teaching assistant. I would also like to thank Dr. Marcus Holzinger for encouraging me to pursue research in orbital mechanics and Dr. Nathan Strange and the Jet Propulsion Labo- ratory for hosting me for a life-changing summer internship. Finally, I would like to thank my friends and family and especially my partner for always being there to support me and believe in me when the challenges of an academic career felt insurmountable. iii Contents Acknowledgments iii List of Tables vi List of Figures vii Summary xi 1 Observations of the high-redshift Universe1 1.1 Observational Techniques and Constraints............... 2 1.1.1 Cosmological Distances and Flux................ 3 1.1.2 Noise and Optical Effects .................... 5 1.2 Modeling an Unseen Universe...................... 7 1.2.1 The Grand Narrative....................... 7 1.3 Overview of Thesis............................ 10 2 Radiative transfer in cosmological simulations 11 2.1 The Radiative Transfer Equation .................... 11 2.1.1 Extinction............................. 11 2.1.2 Scattering............................. 17 2.1.3 Emission.............................. 19 2.1.4 Point Sources........................... 24 2.1.5 Constructing the Equation.................... 30 2.2 Numerical Solution Methods....................... 32 2.2.1 Adaptive Ray Tracing (Enzo).................. 33 2.2.2 Monte Carlo (Hyperion).................... 34 3 Exploring the spectra of high-redshift galaxies in the Renaissance Simulations 37 3.1 Introduction and Background ...................... 38 3.1.1 EoR Galaxy Observations .................... 38 3.1.2 EoR Galaxy Simulations..................... 39 3.1.3 Synthetic Observations...................... 41 3.2 Research Methods............................. 42 3.2.1 Simulation Techniques...................... 42 3.2.2 Halo Analysis........................... 45 iv 3.2.3 Spectrum Building ........................ 46 3.2.4 Filters, Magnitudes, and Images................. 49 3.3 Results................................... 54 3.3.1 Aggregate Halo Statistics..................... 55 3.3.2 Individual Halos ......................... 68 3.4 Discussion................................. 71 3.4.1 Comparable Works........................ 72 3.4.2 Applications............................ 74 3.4.3 Future Enhancements ...................... 74 3.5 Conclusions................................ 75 4 Emission lines, population III stars, and X-ray binaries 78 4.1 Introduction and Background ...................... 79 4.1.1 Population III stars and X-ray Binaries............. 79 4.1.2 Emission Lines .......................... 80 4.2 Methods.................................. 80 4.2.1 Stellar Spectra .......................... 81 4.2.2 Emission Line Extinction..................... 84 4.2.3 High Mass X-Ray Binaries.................... 90 4.2.4 Spectral Energy Distribution Analysis ............. 93 4.3 Results................................... 93 4.3.1 Stellar Population Merger Scenario............... 95 4.3.2 Population III Galaxy Scenario ................. 102 4.3.3 Emission Lines .......................... 105 4.3.4 Aggregate Spectrographic and Photometric Results . 109 4.4 Discussion................................. 114 4.5 Conclusion................................. 117 5 Observational signatures of massive black hole formation in the early universe 119 5.1 Methods.................................. 120 5.1.1 Simulation............................. 120 5.1.2 Radiative Transfer Post-Processing ............... 122 5.2 Results................................... 124 5.2.1 Comparisons to Literature.................... 137 6 Conclusions and future work 139 6.1 Future Work................................ 140 A Theory of World Structure 146 Bibliography 149 v List of Tables 3.1 Linear regression analysis between flux (z = 15) and stellar mass.... 60 3.2 Linear regression analysis between apparent magnitude (z = 15) and stellar mass................................. 61 3.3 Individual halo properties ........................ 68 4.1 Individual metal-poor halo properties................... 112 vi List of Figures 2.1 Gas specific luminosity versus temperature............... 23 2.2 Hertzsprung-Russell diagram from the Gliese and Jahreiß [1] catalog of nearby stars produced by Richard Powell............... 25 2.3 Specific luminosity of stars by metallicity. Population III specific lumi- nosities for the PopIII.1 and PopIII.2 IMF prescriptions are presented. 26 2.4 Galaxy specific luminosities versus stellar mass fraction for haloes in the \rare peak" of the Renaissance Simulations[2] at z = 15....... 28 3.1 Halo number counts in the Renaissance Simulations rare peak region for star-hosting haloes as a function of halo mass (left) and stellar mass (right).................................... 43 3.2 A sample synthetic spectra placed at z = 15 overlaid with selected HST and JWST filters.............................. 50 3.3 Contour histograms and scatter plots of total bolometric luminosity versus halo mass and stellar mass..................... 52 3.4 Colour-colour plots of star-hosting haloes coloured by their mass-averaged stellar age and stellar masses. ...................... 53 3.5 Colour J200w -J277w versus stellar mass coloured by the mass-weighted stellar age.................................. 54 3.6 The evolution of average colour-colour plot as the spectra are redshifted in the range z = 8 − 15........................... 55 3.7 Emission line measures as a function of stellar mass........... 56 vii 3.8 Contour histograms and scatter plots corresponding to the Hubble f160w and JWST f277w filters. ..................... 61 3.9 Stacked galactic spectra with mean values in blue and 1σ bands in grey in different stellar mass range and gas-poor and gas-rich haloes.... 62 3.10 S ii and N ii BPT diagrams of the emission line ratios coloured by specific star formation rate. ....................... 62 3.11 The UV slope of averaged spectra versus stellar mass.......... 64 3.12 Synthetic imaging and spectrum of Halo A................ 65 3.13 Variations of emergent flux and gas properties of Halo A along different lines of sight. ............................... 66 9 7 3.14 Halo B (Mtot = 1:62 × 10 M , M? = 3:4 × 10 M ) plotted in the same manner as Halo A in Figure 3.12..................... 67 4.1 Top Row: Total extinction profiles for gas and metal emission lines and a gas absorption continuum as a function of wavelength and tempera- ture. Bottom Row: Corresponding emission profiles assuming thermo- dynamic equilibrium............................ 82 4.2 Isothermal cross-sections of extinction profiles.............. 85 4.3 Number of Population III stars, number of X-ray binaries, fraction of X-ray binaries, and fraction of high mass X-ray binaries for a burst of star formation............................... 88 4.4 Multi-color disk (MCD) and power law (PL) components of a SED from a 40 M black hole accreting at the Eddington Limit....... 90 4.5 Plot of total metal-free stellar mass versus total halo mass coloured by metal-free stellar fraction of the total stellar mass............ 92 4.6 Top row: Integral of density-weighted mean density, density-weighted mean temperature, and density-weighted mean metallicity. Bottom row: Integrated total emission, scattering per unit area, and integrated dust emission................................ 94 viii 4.7 Top Row: The spectra of Halo A shown before the application of lines with lines from gas in close proximity to the star and after extinction. Bottom row: The ratio of emission to the nearest wavelength in the intrinsic spectrum and the mean difference between the mean emission wavelength and the mean absorption wavelength for the combination of both gas and dust............................ 96 4.8 A compact Population III stellar cluster plotted in the same manner as Figure 4.6. ............................... 97 4.9 Halo B plotted in the same manner as Figure 4.7............ 98 4.10 Left: Four most common emission lines amongst halos in our simulation with active Population III stars and only metal-enriched stars . Right: Emission