Observational evidence shows that gravitational lensing induces an angular correlation between the distribution of galaxies and much more distant QSO’s. We use weak gravitational lensing theory to calculate this angular correlation, updating previous calculations and presenting new results exploring the dependence of the correlation on the large-scale structure. We study the dependence of the p...

High-energy photons from pair annihilation of dark matter particles contribute to the cosmic gamma-ray background (CGB) observed in a wide energy range. Since dark matter particles are weakly interacting, annihilation can happen only in high density regions such as dark matter halos. The precise shape of the energy spectrum of CGB depends on the nature of dark matter particles — their mass and ...

We reconsider the inference of spatial power spectra from angular clustering data and show how to include correlations in both the angular correlation function and the spatial power spectrum. Inclusion of the full covariance matrices loosens the constraints on large-scale structure inferred from the APM survey by over a factor of two. We present a new inversion technique based on singular value...

We present improved results on the measurement of the angular power spectrum of the Cosmic Microwave Background (CMB) temperature anisotropies using the data from the last A flight. This refined analysis is obtained by using the 6 most sensitive photometric pixels in the CMB bands centered at 143 and 217 GHz and 20% of the sky, mostly clear of foregrounds. Using two different cross-corre...

We review recent work aimed at showing how global topolog-ical defects influence the shape of the angular power spectrum of the cosmic microwave background radiation on small scales. While Sachs–Wolfe fluctuations give the dominant contribution on angular scales larger than about a few degrees, on intermediate scales, 0.1 • < ∼ θ < ∼ 2 • , the main rôle is played by coherent oscillations in the...

Archeops is a balloon-borne experiment designed to measure the temperature fluctuations of the CMB on a large region of the sky (≃ 30%) with a high angular resolution (10 arcminutes) and a high sensitivity (60µK per pixel). Archeops will perform a measurement of the CMB anisotropies power spectrum from large angular scales (ℓ ≃ 30) to small angular scales (ℓ ≃ 800). Archeops flew for the first ...

The shape of the angular power spectrum of galaxies in the linear regime is defined by the horizon size at the matter-radiation equality. When calibrated by cosmic microwave background measurements, the shape of the clustering spectrum can be used as a standard ruler to estimate angular diameter distance as a function of redshift at which galaxy clustering is measured. We apply the proposed cos...

The angular power spectrum Cl is extracted from the 4 year COBE DMR data with a 20◦ galactic cut, using the narrowest window functions possible. The average power in eight multipole bands is also computed, and plotted together with a compilation of power spectrum measurements from other experiments. The COBE results are found to be consistent with the n = 1 power spectrum with the normalization...

Observations of the microwave sky using the Python telescope in its fifth season of operation at the Amundsen-Scott South Pole Station in Antarctica are presented. The system consists of a 0.75 m offaxis telescope instrumented with a HEMT amplifier-based radiometer having continuum sensitivity from 37-45 GHz in two frequency bands. With a 0.91 × 1.02 beam the instrument fully sampled 598 deg of...

We consider the distortion in the cosmic microwave background (CMB) due to galactic winds at high redshift. Winds outflowing from galaxies have been hypothesized to be possible sources of metals in the intergalactic medium, which is known to have been enriched to 10−2.5 Z⊙ at z ∼ 3. We model these winds as functions of mass of the parent galaxy and redshift, assuming they activate at a common i...