Session C1: Astronomy and Cosmology II

Taking the Measure of the Universe with CHIME (the Canadian Hydrogen Intensity Mapping Experiment)

Cosmology is the study of the physical universe and the questions being addressed are profound. How old is the universe? How did it begin? Is it finite or infinite? Remarkably, these questions are starting to be answered. Thanks to precise observations from an array of new instrumentation, we know the age of the universe to better than 1%: 13.77 billion years. We know the content of the universe is dominated by dark matter (26%) and dark energy (71%). Ordinary atomic matter makes up only 4.6% of the universe.To the best of our knowledge the universe is infinite, or very large, and it will continue expanding forever, indeed at an ever faster rate due to dark energy. These conclusions are made possible by our ability to detect and characterize cosmic sound waves, called baryon acoustic oscillations (BAO) that long ago propagated in the universe. The BAO places a distinctive imprint on both the cosmic microwave background radiation and the distribution of galaxies that we observe nearby. I will summarize recent measurements and give an overview of a new digital radio telescope being built in Penticton, B.C., called CHIME. CHIME will map roughly 5% of the entire observable universe. Data from CHIME will tightly constrain the expansion history of the universe and the properties of the dark energy causing it.   

Characterization of CHIME Pathfinder beam using source transits

The Canadian Hydrogen Intensity Mapping Experiment (CHIME) aims to study the accelerating expansion of the Universe by tracing the large scale matter distribution in the Universe. The Pathfinder is an on-site prototype used for developing instrumentation and to test calibration and analysis techniques. The ultimate aim of the calibration is to obtain sky data with sufficient signal-to-noise ratio in order to detect the faint cosmological signal, by filtering out the foreground. The focus of this talk is the calibration of the CHIME Pathfinder beam response by analysing transits from radio sources at a range of declinations and assessing the current beam model. The current model takes into account a secondary bounce in the primary beam due to the reflector structure. There is a phase shift between the measurements and GRASP beam simulations in the anticipated frequency ripple attributed to the secondary bounce. This implies that the current model needs improvement and requires further investigation. This analysis provides a unique opportunity to prepare for the calibration of the full instrument and improve our understanding of the working of this type of telescope.   

Modeling Axion Structure Formation with N-Body Codes for ADMX

Axions are a well-motivated candidate for the dark matter. Direct axion search experiments, like the Axion Dark-Matter Experiment (ADMX), can resolve the local axion-halo velocity to better than $\sim 10^{-5} c$. However, there isn’t an agreed-upon model of axion structure formation. Hence, there is some uncertainty as to whether structures seeded by axion dark matter form differently than structures seeded by standard pressureless cold dark matter. This talk proposes an alternative model and outlines a plan to simulate its axion structures by leveraging ChaNGa, a powerful N-body structure-formation code.   

Nonaxisymmetric Instabilities Driven by Star/Disk Coupling

Coupling of stellar and disk modes changes the stability properties of nonaxisymmetric modes in astrophysical systems in a variety of ways. For example, coupling drives instability in slowly rotating stars, stars otherwise stable to nonaxisymmetric instabilities (Yuan \& Cassen 1985), and coupling leads to new types of nonaxisymmetric instabilities such as the one-armed modes driven by the {\it indirect} stellar potential discovered by Adams, Ruden, \& Shu (1989). We report our investigations of star/disk coupling in which we self-consistently determine equilibrium stellar structures as well as their surrounding disks. We study two sets of models. Set 1, systems with stars in uniform rotation that are below the secular instability thresholds for barlike modes in isolated stars. Set 2, systems with stars in differential rotation where the stars are dynamically unstable to barlike modes in isolated stars. For Set 1, resolved stars do not have large effects on the most unstable modes, the $m$ = 1 modes. For Set 2, star/disk coupling drives different modes in stars unstable to and stable to $m$ = 2 dynamic instatbilities. For the former, stellar modes are driven unstable bydisk modes while for the latter, the stars themselves are dynamically unstable.   

Quantum Gravity Phenomenology from the Generalized Uncertainty Principle

Quantum gravity theories predict modifications of the Heisenberg Uncertainty Principle to the Generalized Uncertainty Principle (GUP), which in turn predicts the existence of a minimum measurable length. In this presentation I will show how GUP modifies standard quantum mechanics, for example that of quantum optical systems and the theory of angular momentum, and how these can be used to test quantum gravity effects in the laboratory.   

Unification of Quantum Mechanics and General Relativity: Geometrical Nature of Matter and Multiple Levels of Universes

Spacetimematter is a five dimensional geometry where matter is baked into geometry as a new dimension. Every event point of spacetimematter follows the uncertainty principle, which limits the accuracy of the measurement of its space, time, and matter coordinates turning it into a Space-Time-Matter (STM) geometrical quantum with space, time, and matter edges. The Universe consists of a hierarchical levels of universes where each level has its own level of spacetimematter and quantum state functions. I'll show that non-ordinary matter and energy coming from the non-zeroth levels of universes together form the dark matter and dark energy. I'll present new quantum and general relativity field equations for each level of universe which together unify quantum mechanics and general relativity and the four fundamental forces of nature. I'll then use actual astronomical data and a simple theoretical model to derive the physical constants of the first level of universe and show that they vary from their counterparts in the zeroth level of universe (i.e. ordinary universe). I'll also provide a quantum mechanism for black hole characteristics such as singularity and space-time reversal and show how my approach resolves black hole information paradox.