Related papers: Large Scale Fluctuations in the X-Ray Background

The cosmic infrared background from galaxies should have a minimum fluctuation of the order of 10\% on angular scales probed by the DIRBE (Diffuse Infrared Background Experiment) on board COBE (Cosmic Background Explorer). We present the…

We have measured the spectrum of the Cosmic X-ray Background (CXB) in the 2-8 keV range with the high throughput EPIC/MOS instrument onboard XMM-Newton. A large sample of high galactic latitude observations was used, covering a total solid…

Measurements of the intensity of the cosmic X-ray background (XRB) carried out over small solid angles are subject to spatial variations due to the discrete nature of the XRB. This cosmic variance can account for the dispersion of XRB…

We report first results for the cosmic infrared background (CIB) fluctuations at 1.25, 1.65 and 2.17 micron obtained from long exposures constructed from 2MASS standard star fields. We have co-added and analyzed scans from one such field…

Cross-correlations of the WMAP full sky K, Ka, Q, V, and W band maps with the 1.4 GHz NVSS source count map and the HEAO I A2 2-10 keV full sky X-ray flux map are used to constrain rms fluctuations due to unresolved microwave sources in the…

The COBE detection of microwave anisotropies provides the best way of fixing the amplitude of cosmological fluctuations on the largest scales. We discuss the impact of this new, precise normalization and give fitting formulae for the…

We present the results of a detailed study of how isocurvature axion fluctuations are converted into adiabatic metric perturbations through axion decay, and discuss the constraints on the parameters of pre-big bang cosmology needed for…

Scattering of cosmic microwave background (CMB) radiation in galaxy clusters induces a polarization signal proportional to the CMB quadrupole anisotropy at the cluster's location and look-back time. A survey of such remote quadrupole…

In this thesis we investigate several aspects related to the theory of fluctuations in the Cosmic Microwave Background. We develop a new algorithm to calculate the angular power spectrum of the anisotropies which is two orders of magnitude…

When modelling the ionisation of gas in the intergalactic medium after reionisation, it is standard practice to assume a uniform radiation background. This assumption is not always appropriate; models with radiative transfer show that…

Angular power spectra of optical and infrared background anisotropies at wavelengths between 0.5 to 5 $\mu$m are a useful probe of faint sources present during reionization, in addition to faint galaxies and diffuse signals at low redshift.…

Strong intergalactic shocks are a natural consequence of structure formation in the universe. They are expected to deposit large fractions of their energy in relativistic electrons (xi_e~0.05 according to SNR observations) and magnetic…

We use Swift/BAT Earth occultation data at different geomagnetic latitudes to derive a sensitive measurement of the Cosmic X-ray background (CXB) and of the Earth albedo emission in the 15--200 keV band. We compare our CXB spectrum with…

Two years of microwave background observations with the Cosmic Background Imager (CBI) have been combined to give a sensitive, high resolution angular power spectrum over the range 400 < l < 3500. This power spectrum has been referenced to…

The Sachs-Wolfe effect is known to produce large angular scale fluctuations in the Cosmic Microwave Background Radiation (CMBR) due to gravitational potential fluctuations. We show how the angular correlation function of the CMBR can be…

We present a formalism for computing time-dependent fluctuations in the cosmological photoionizing radiation background, extending background fluctuations models beyond the steady-state approximation. We apply this formalism to estimate…

We discuss the issue of how precisely we can measure the primordial power spectrum by using future observations of 21 cm fluctuations and cosmic microwave background (CMB). For this purpose, we investigate projected constraints on the…

We present a new method for time-efficient and accurate extraction of the power spectrum from future cosmic microwave background (CMB) maps based on properties of peaks and troughs of the Gaussian CMB sky. We construct a statistic…

Using a simple analytic model based on seed superposition we obtain the spectrum of microwave background perturbations induced by cosmic strings on all angular scales larger than about 2 armin. We assume standard recombination in an…

ABSRACT: We review recent progress on testing the hypothesis of the existence of cosmic string perturbations in microwave background maps. Using an analytical model for the string network we show that the predicted amplitude and spectrum of…