Related papers: Measuring the power spectrum of density fluctuatio…
We propose a new, simple, dedicated X-ray mission to measure the power spectrum of density fluctuations in the Universe, by accurately mapping the X-ray background on the whole sky on scales of arounf one sq deg. Since the method relies on…
The X-Ray Background (XRB) probes structure on scales intermediate between those explored by local galaxy redshift surveys and by the COBE Microwave Background measurements. We predict the large scale angular fluctuations in the XRB,…
The X-ray background (XRB) is produced by a large number of faint sources distributed over a wide range of redshifts. The XRB carries information on the spatial distribution and evolution of these sources. The goals of the paper are: 1. to…
We have studied the fluctuations of the soft (0.9-2 keV) X-ray background intensity for ~10 arcmin and ~2 arcmin beam sizes, using 80 high galactic latitude medium-deep images from the ROSAT position sensitive proportional counter (PSPC).…
Fluctuations of the surface brightness of cosmic X-ray background (CXB) carry unique information about faint and low luminosity source populations, which is inaccessible for conventional large-scale structure (LSS) studies based on resolved…
We present an attempt to measure the large angular scale fluctuations in the X-Ray Background (XRB) from the HEAO1-A2 data, expressed in terms of spherical harmonics. We model the harmonic coefficients assuming a power spectrum and an…
Several independent measurements have confirmed the existence of fluctuations ($\delta F_{\rm obs}\approx 0.1 \rm nW/m^{2}/sr$ at $3.6 \rm \mu m$) up to degree angular scales in the source-subtracted Near InfraRed Background (NIRB) whose…
The large-scale structure of high-redshift galaxies produces correlated anisotropy in the far-infrared background (FIRB). In regions of the sky where the thermal emission from Galactic dust is well below average, these high-redshift…
We discuss cosmological inference from galaxy surveys at low and high redshifts. Studies of optical and IRAS redshift surveys with median redshift ${\bar z} \sim 0.02$ yield measurements of the density parameter $\Omega$ and the…
We present Ginga measurements of the spatial fluctuations in the diffuse X-ray background. When combined with earlier results, the new data constrain the extragalactic log N - log S relation in the 2-10 keV energy band to a form close to…
The X-ray background is generated by various classes of objects and variety of emission mechanisms. Relative contribution of individual components depends on energy. The goal is to assess the integral emission of the major components of the…
We measure the spatial fluctuations of the Near-Infrared Extragalactic Background Light (NIREBL) from 2$^{\circ}$ to 20$^{\circ}$ in angular scale at the 1.6 and 2.2 $\mu$m using data obtained with Near-Infrared Spectrometer (NIRS) on board…
Unresolved near-infrared background anisotropies are expected to have contributions from the earliest galaxies during reionization and faint, dwarf galaxies at intermediate redshifts. Previous measurements were unable to conclusively…
Fluctuations in the brightness of the background radiation can lead to confusion with real point sources. Such background emission confusion will be important for infrared observations with relatively large beam sizes since the amount of…
The Near Infrared Background (NIRB) is one of a few methods that can be used to observe the redshifted light from early stars at a redshift of six and above. Fluctuations of the NIRB can provide information on the first structures, such as…
Fluctuations of the soft X-ray background are investigated using harmonic analysis. A section of the ROSAT All-Sky Survey around the north galactic pole is used. The flux distribution is expanded into a set of harmonic functions and the…
The source-subtracted cosmic infrared background (CIB) fluctuations uncovered in deep Spitzer data cannot be explained by known galaxy populations and appear strongly coherent with unresolved cosmic X-ray background (CXB). This suggests…
Turbulent processes at work in the intracluster medium perturb this environment, displacing gas, and creating local density fluctuations that can be quantified via X-ray surface brightness fluctuation analyses. Improved knowledge of these…
The shape of the curves defined by the counts of radio sources per unit area as a function of their flux density was one of the earliest cosmological probes. Radio source counts continue to be an area of interest, used to study the relative…
We have carried out a fluctuation analysis in four bands (R4, R5, R6 and R7 corresponding to 0.44-1.01 keV, 0.56-1.21 keV, 0.73-1.56 keV and to 1.05-2.04 keV respectively) of two very deep ROSAT PSPC observations in directions where the…