Equations to investigate fluctuations in cosmic x-ray background radiation due to pointlike sources at high-redshift are formulated in a systematic way. The angular power spectrum of x-ray background fluctuations is investigated from large scales to small scales in various cosmological models such as open universe models and models with the cosmological constant, assuming a simple evolution mod...

A modification to the Friedmann Robertson Walker equation is proposed in which the universe is flat, matter dominated, and accelerating. An additional term, which contains only matter or radiation (no vacuum contribution), becomes the dominant driver of expansion at a late epoch of the universe. During the epoch when the new term dominates, the universe accelerates; we call this period of accel...