Bulletin of the American Physical Society
2005 72nd Annual Meeting of the Southeastern Section of the APS
Thursday–Saturday, November 10–12, 2005; Gainesville, FL
Session DC: Relativity, Cosmology and Astrophysics |
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Chair: Steve Detweiler, University of Florida Room: Hilton Azalea |
Thursday, November 10, 2005 2:00PM - 2:12PM |
DC.00001: Classical Fields in Special Relativity Chris Vuille Classical field equations are ordinarily postulated, imposed on a background space-time. Here it is shown that in relativity such fields can be a natural consequence of the underlying space-time structure; they need not and can not be arbitrarily defined. Indeed, under general assumptions, a classical field that results in a four-acceleration on flat space-time must satisfy Maxwell's equations. The field can also be a solution of a Proca equation, if it is assumed, in addition, to be derived from a vector potential with zero divergence. Some analogous result may be possible for quantum fields, given the proper underlying spacetime structure. [Preview Abstract] |
Thursday, November 10, 2005 2:12PM - 2:24PM |
DC.00002: Towards Metric Perturbations of Kerr Black Holes Larry Price, Bernard Whiting Inspired by early work on perturbations of Kerr, we've developed a formulation of metric perturbation theory phrased in the spin coefficient formalsim of Newman and Penrose as modified by Geroch, Held and Penrose (GHP). In turn, this has driven the development of a Maple package, GHPTools, for performing the necessary calculations. In this talk I'll explain the basic ideas behind these tools and techniques and showcase some results obtained in the Schwarzschild geometry. Time permitting, I'll also discuss work in progress in the Kerr geometry. [Preview Abstract] |
Thursday, November 10, 2005 2:24PM - 2:36PM |
DC.00003: Magnetic Fields from Cosmological Perturbations Ethan Siegel, James Fry Strong observational evidence indicates the presence of magnetic fields on galactic and supergalactic scales. Mechanisms that amplify an initially small seed field are known (such as the dynamo mechanism for spiral galaxies); however, the origins of these initial seed fields are unknown. In this talk, we show that magnetic fields can arise directly from cosmological perturbations in the early universe. Due to the differing scattering cross sections of protons and electrons with photons, local charge separations arise on all cosmological scales. As a result, electric and magnetic fields are then generated in the very early universe. Electric fields created in this way decay at early times, but magnetic fields may remain stable through both the onset of matter-domination and recombination, persisting until the present day. Thus, cosmological perturbations could provide a natural and elegant explanation for the existence of magnetic fields on galactic and larger scales. [Preview Abstract] |
Thursday, November 10, 2005 2:36PM - 2:48PM |
DC.00004: 2-Body Einstein-Infeld-Hoffman Equations from Boosted Schwarzschild Black Holes Michael Ian Vega We present an elementary derivation of the 2-body EIH equations, which are 1-PN accurate equations of motion for a sufficiently separated binary system of non-spinning black holes. The 3-acceleration of one black hole is calculated by writing down the geodesic equation in the boosted geometry of the other black hole up to the appropriate post-Newtonian order. Harmonic coordinates are used for the locally inertial frames around each of the black holes and for the flat global background. [Preview Abstract] |
Thursday, November 10, 2005 2:48PM - 3:00PM |
DC.00005: Thin film surface treatments for lowering dust adhesion and ultraviolet degradation of Mars Exploration Rover calibration targets Firouzeh Sabri, Randolph Duran, Tim Werhner, Dan Britt The correct interpretation and radiometric modeling of images received from the Panoramic Camera, on board Mars Exploration Rover relies on precise color calibration. An imperative property of the calibration targets is that their surfaces must follow Lambert's Cosine law of reflection. This translates into surface heterogeneities that can act as trapping sites for the micrometer-size dust particles present in Mars atmosphere, caused by frequent dust storms. The tacky nature of the polymer that is currently in use (RTV655) adds to the dust accumulation and adhesion problem. In addition, the polymer undergoes chemical changes when exposed to intense UV radiation existent on Mars. As a result, significant degradation of optical resolution is observed. However, properties of RTV655 such as toughness, flexibility, low outgassing, and wide range temperature stability are superior to other materials available. Therefore, our approach towards eliminating these problems has been to maintain the original design structure yet apply non-invasive thin film technology consisting of a polymer-metal sandwich structure that would create a smooth and transparent finish with inert chemical properties. [Preview Abstract] |
Thursday, November 10, 2005 3:00PM - 3:12PM |
DC.00006: Two Dimensional Fluid Flow in a Barred Galaxy Potential Lee Culver, Gary Hunter, James Espinosa, Julie Talbot, Paul Fisher, James Woodyard We describe two-dimensional models for near-steady state gas flow in a bar potential. Such models serve as a first step in describing the thin disks of barred galaxies. Realistic three-dimensional models of barred galaxies remain a challenge to existing theory and so we proceed by thoroughly testing our tools in limited cases as we increase the complexity of the model. Our model begins with a steady-state solution of the hydrodynamic equations based upon the Hachisu Self-Consistent Field Technique and compares the resulting motions of the gas to that of stars determined by traditional integrations. [Preview Abstract] |
Thursday, November 10, 2005 3:12PM - 3:24PM |
DC.00007: Perturbative Solutions of the Einstein Klein-Gordon Equations Gianluca Puliti, Mara Jennings, Vincent Mamo, Chris Vuille As the Klein-Gordon equation is important in quantum theory and describes spin-0 particles, it is of interest to discover the nature of the gravity field such particles would be expected to create. In this paper, we solve the static, massive Einstein-Klein-Gordon (EKG) equations in perturbation, and compare the results with a similar calculation developed for the Einstein-Proca system. Subsequently, we study the massless static Klein-Gordon equation, and compare the result to the Reissner-Nordstrom metric. [Preview Abstract] |
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