We test the hypothesis that the starless cores may be gravitationally bound clouds supported largely by thermal pressure by comparing observed molecular line spectra to theoretical spectra produced by a simulation that includes hydrodynamics, radiative cooling, variable molecular abundance, and radiative transfer in a simple one-dimensional model. The results suggest that the starless cores can...

There is abundant evidence that heating processes in the central regions of elliptical galaxies have both prevented large-scale cooling flows and assisted in the expulsion of metal rich gas. We now know that each such spheroidal system harbours in its core a massive black hole weighing ca. 0.13% of the mass in stars and also know that energy was emitted by each of these black holes with an effi...

Thermal surface emissions have now been detected from more than a dozen isolated neutron stars, including radio pulsars, radioquiet neutron stars and magnetars. These detections can potentially provide important information on the interior physics, magnetic fields, and surface composition of neutron stars. Understanding the properties of matter and radiative transfer in strong magnetic fields i...

Non-radiative (phonon scattering) lifetimes are calculated for asymmetric quantum well structures in the AlGaAs/GaAs materials system. Structures are designed in a 3-level optically pumped laser configuration, and tuned for emission in the terahertz frequency range. For emission frequencies below 8.7THz, the energy gap of the lasing levels is less than the LO phonon energy in GaAs, which leads ...

In the near field, radiative heat transfer can exceed the prediction from Planck's law by several orders of magnitude, when the interacting materials support surface polaritons in the infrared range. However, if the emitter and absorber are made from two different materials, which support surface polariton resonances at different frequencies, the mismatch between surface polariton resonance fre...

This work presents efficient solution techniques for radiative transfer in the smoothed particle hydrodynamics discretization. Two choices that impact efficiency are how material and radiation energy coupled, which determines number of iterations needed to converge emission source, diffusion equation is solved, must be done each iteration. The coupled equations solved using an inexact Newton it...