Radio relics are extended regions of synchrotron radio emission that have been found in the outskirts of a few dozen galaxy clusters. Relics are often associated with clusters undergoing merger activity. They are not associated optically with a...
After decades of searching we have yet to find the progenitor systems for type Ia supernovae. In fact most of what we know about this homogeneous class of supernovae is from spectral features associated with the incinerated remains of the C+O white...
Quantum wires and dots can be created by patterning inhomogeneous strain on semiconductor quantum wells. I have used laser spectroscopic methods to study the carrier transfer from the host quantum well to quantum wires and dots. For quantum dot...
Magneto-spectroscopy is used to characterize the confinement properties of strain-induced quantum wires and dots. The wires and dots are low energy regions in an ordinary GaAs/AlGaAs quantum well that are formed when microscopic...
The accelerated expansion of space in the Universe has been known for two decades. However, finding a plausible theory that describes this expansion is more difficult: Taking general relativity for granted requires us to stipulate the existence of...
The new APM South Equatorial Strip Catalog $({-}17\sp\circ.5<\delta<2\sp\circ.5)$ is used to select a sample of early-type galaxies in three directions: (1) 15h10-16h10; (2) 20h30-21h50; (3) 00h10-01h30. The distances and peculiar motions of...
Relativity (Physics). ; Anisotropy -- Mathematical models. ; Einstein field equations. ; Newtonian fluids. ; Astrophysics.
We study the effects of anisotropic pressure on the properties of spherically symmetric, gravitationally bound spheres. We consider the full general-relativistic and Newtonian treatment of this problem and obtain exact solutions for various forms...
Cosmic acceleration could be an effect of a ""dark energy"" fluid pervading the Universe. It could also be an indication that general relativity is not the correct theory of gravity at cosmological length scales. Unfortunately, observations of the...
In this thesis, the dynamics of long-lived, time-dependent, coherent field configurations, known as oscillons, are investigated in the presence of an expanding background. In a (1+1)-dimensional expanding spacetime, scalar-field oscillon lifetimes...
A sample of 46 previously unidentified, intermediate- to high-redshift, near-infrared (NIR)-selected galaxy clusters have been discovered in the Andromeda catalog of the Oxford Dartmouth Thirty Degree Survey (ODTS). These clusters vary from low- to...