Electromagnetic Wave Collapse in a Radiation Background

Cherenkov Radiation in a Gravitational Wave Background

A covariant criterion for the emission of Cherenkov radiation in the field of a non-linear gravitational wave is considered in the framework of exact integrable models of particle dynamics and electromagnetic wave propagation. It is shown that vacuum interacting with curvature can give rise to Cherenkov radiation. The conically shaped spatial distribution of radiation is derived and its basic p...

Electromagnetic radiation induced by a gravitational wave

Anisotropies of Cosmic Background Radiation from a Local Collapse

We present an exact solution of the anisotropies of cosmic background radiation (CBR) from a local collapse described by a spherical over-dense region embedded in a flat universe, with the emphasis on the relationship between the dipole (∆T/T)d and the quadrupole (∆T/T)q anisotropy. This result has been used to examine the kinematic quadrupole correction (∆T/T)q = (∆T/T) 2 d/2, which is usually...

Gamma background radiation in Yazd province A preliminary report

 ABSTRACTBackground: There are relatively rich uranium mines in regions of Saghand and Bafgh in Yazd province. This survey was carried out to provide a map of ambient gamma radiation of Yazd province and the probable effects of the existence of these mines on background radiation dose rates.Materials and Methods: The measurements of the outdoor and indoor–environmental exposures (including cosm...

Radiation-Hydrodynamical Collapse of Pregalactic Clouds in the Ultraviolet Background

To elucidate the effects of the UV background radiation on the collapse of pregalactic clouds, we implement a radiation-hydrodynamical calculation, combining onedimensional spherical hydrodynamics with an accurate treatment of the radiative transfer of ionizing photons. Both absorption and scattering of UV photons are explicitly taken into account. It turns out that a gas cloud contracting with...