Detection of Cosmic Microwave Background Structure in a Second Field with the Cosmic Anisotropy Telescope

Abstract

We describe observations at frequencies near 15 GHz of the second 2x2 degree field imaged with the Cambridge Cosmic Anisotropy Telescope (CAT). After the removal of discrete radio sources, structure is detected in the images on characteristic scales of about half a degree, corresponding to spherical harmonic multipoles in the approximate range l= 330--680. A Bayesian analysis confirms that the signal arises predominantly from the cosmic microwave background (CMB) radiation for multipoles in the lower half of this range; the average broad-band power in a bin with centroid l=422 (theta = 51') is estimated to be Delta_T/T=2.1^{+0.4}_{-0.5} x 10^{-5}. For multipoles centred on l=615 (theta =35'), we find contamination from Galactic emission is significant, and constrain the CMB contribution to the measured power in this bin to be Delta_T/T <2.0 x 10^{-5} (1-sigma upper limit). These new results are consistent with the first detection made by CAT in a completely different area of sky. Together with data from other experiments, this new CAT detection adds weight to earlier evidence from CAT for a downturn in the CMB power spectrum on scales smaller than 1 degree. Improved limits on the values of H_0 and Omega are determined using the new CAT data.

5 pages, 5 figures (gif), submitted to MNRAS

References in corpus (6)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• A Catalog of 200 Galaxy Clusters Serendipitously Detected in the ROSAT PSPC Pointed Observations
• What Can Cosmic Microwave Background Observations Already Say About Cosmological Parameters in Open and Critical-Density Cold Dark Matter Models?
• Structure formation by cosmic strings with a cosmological constant
• Mapping the CMB II: the second flight of the QMAP experiment
• Near-infrared and X-ray obscuration to the nucleus of the Seyfert 2 galaxy NGC 3281

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