Browsing Astronomy and Astrophysics by Title
Now showing items 67-86 of 160
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An Improved Treatment of Optics in the Lindquist-Wheeler Models
We consider the optical properties of Lindquist-Wheeler (LW) models of the Universe. These models consist of lattices constructed from regularly arranged discrete masses. They are akin to the Wigner-Seitz construction of ... -
Inhomogeneous Gravity
We study the inhomogeneous cosmological evolution of the Newtonian gravitational 'constant' G in the framework of scalar-tensor theories. We investigate the differences that arise between the evolution of G in the background ... -
Islands in the landscape
The string theory landscape consists of many metastable de Sitter vacua, populated by eternal inflation. Tunneling between these vacua gives rise to a dynamical system, which asymptotically settles down to an equilibrium ... -
Isocurvature constraints on portal couplings
(2016-06) -
The isotropic blackbody CMB as evidence for a homogeneous universe
(American Physical Society, 2012-08-01)The question of whether the Universe is spatially homogeneous and isotropic on the largest scales is of fundamental importance to cosmology, but has not yet been answered decisively. Surprisingly, neither an isotropic ... -
Living in a Void: Testing the Copernican Principle with Distant Supernovae
(2008-07-09)A fundamental presupposition of modern cosmology is the Copernican Principle; that we are not in a central, or otherwise special region of the Universe. Studies of Type Ia supernovae, together with the Copernican Principle, ... -
MagAO IMAGING OF LONG-PERIOD OBJECTS (MILO). II. A PUZZLING WHITE DWARF AROUND THE SUN-LIKE STAR HD 11112
(Institute of Phisics, 2016-11)HD 11112 is an old, Sun-like star that has a long-term radial velocity (RV) trend indicative of a massive companion on a wide orbit. Here we present direct images of the source responsible for the trend using the Magellan ... -
MagAO imaging of long-period objects (MILO). II. A puzzling white dwarf around the sun-like star HD 11112
(IOP Publishing, 2016-11-10)© 2016. The American Astronomical Society. All rights reserved.HD 11112 is an old, Sun-like star that has a long-term radial velocity (RV) trend indicative of a massive companion on a wide orbit. Here we present direct ... -
The Magnetic Part of the Weyl Tensor, and the Expansion of Discrete Universes
(Springer US, 2017-01-27)We examine the effect that the magnetic part of the Weyl tensor has on the large-scale expansion of space. This is done within the context of a class of cosmological models that contain regularly arranged discrete masses, ... -
The Method of Images in Cosmology
We apply the method of images to the exact initial data for cosmological models that contain a number of regularly arranged discrete masses. This allows us to join cosmological regions together by throats, and to construct ...
