We have developed a hit-and-miss Monte Carlo geometric ray-tracing program to compute the scattering phase matrix for concentrically stratified spheres. Using typical refractive indices for water and aerosols in the calculations, numerous rainbow features appear in the phase matrix that deviate from the results calculated from homogeneous spheres. In the context of geometric ray tracing, rainbo...

Conventional radiography seeks to produce, at each location in the image plane, a measure of the x-ray absorption of the object. In this paper, we present a method of determining a much more complete object description at each point, namely the intensity distribution (as a function of angle) of the emerging x-ray beam. From this distribution one can compute many different images, depicting the ...

Fast ray-axis aligned bounding box overlap tests can be performed by utilizing Plücker coordinates. This method tests the ray against the edges comprising the silhouette of the box instead of testing against individual faces. Projection of the edges onto a two-dimensional plane to generate the silhouette is not necessary, which simplifies the technique. The method is division-free and successiv...

Resonant inelastic X-ray scattering and high-resolution X-ray absorption spectroscopy were used to identify the chemical state of a Co electrocatalyst in situ during the oxygen evolution reaction. After anodic electrodeposition onto Au(111) from a Co(2+)-containing electrolyte, the chemical environment of Co can be identified to be almost identical to CoOOH. With increasing potentials, a subtle...

We compute the variation of the beaming fraction with the e ciency of high energy -ray production in the outer gap pulsar model of Romani and Yadigaroglu. This allows us to correct the uxes observed for pulsars in the EGRET band and to derive a simple estimate of the variation of e ciency with age. Integration of this model over the population of young neutron stars gives the expected number of...

We propose to explain the recent observations of GRB early X-ray afterglows with SWIFT by the dissipation of energy in the reverse shock which crosses the ejecta as it is decelerated by the burst environment. We compute the evolution of the dissipated power and discuss the possibility that a fraction of it can be radiated in the X-ray range. We show that this reverse shock contribution behaves ...

Bearing on the model for the time-dependent metagalactic radiation field developed in the first paper of this series, we compute the gamma-ray attenuation due to pair production in photon-photon scattering. Emphasis is on the effects of varying the star formation rate and the fraction of UV radiation assumed to escape from the star forming regions, the latter being important mainly for high-red...

Cosmological implications of clusters of galaxies are discussed with particular attention to their importance in probing the cosmological parameters. More specifically we compute the number counts of clusters of galaxies, Log N – Log S relation, in X-ray and submm bands on the basis of the Press–Schechter theory. As an important step toward breaking the degeneracy among the viable cosmological ...

The possible presence of thermal components in the early X-ray afterglows of γ-ray bursts is investigated. We discuss both the presence of a thermal continuum and, in particular, of collisional X-ray emission lines. We compute the predicted luminosity by a thin plasma for a range of metallicities for the continuum and the Kα lines of the elements Mg, Si, S, Ar, Ca and Fe. We show that light tra...