First results from the Very Small Array -- II. Observations of the CMB

Abstract

We have observed the cosmic microwave background temperature fluctuations in eight fields covering three separated areas of sky with the Very Small Array at 34 GHz. A total area of 101 square degrees has been imaged, with sensitivity on angular scales 3.6 - 0.4 degrees (equivalent to angular multipoles l=150-900). We describe the field selection and observing strategy for these observations. In the full-resolution images (with synthesised beam of FWHM ~ 17 arcmin) the thermal noise is typically 45 microK and the CMB signal typically 55 microK. The noise levels in each field agree well with the expected thermal noise level of the telescope, and there is no evidence of any residual systematic features. The same CMB features are detected in separate, overlapping observations. Discrete radio sources have been detected using a separate 15 GHz survey and their effects removed using pointed follow-up observations at 34 GHz. We estimate that the residual confusion noise due to unsubtracted radio sources is less than 14 mJy/beam (15 microK in the full-resolution images), which added in quadrature to the thermal noise increases the noise level by 6 %. We estimate that the rms contribution to the images from diffuse Galactic emission is less than 6 microK. We also present images which are convolved to maximise the signal-to-noise of the CMB features and are co-added in overlapping areas, in which the signal-to-noise of some individual CMB features exceeds 8.

11 pages, 5 figures, accepted for publication in MNRAS. Replaces original version - more detailed abstract, corrected typos

References in corpus (9)

• A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background
• DASI First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum
• A High Spatial Resolution Analysis of the MAXIMA-1 Cosmic Microwave Background Anisotropy Data
• Towards a free-free template for CMB foregrounds
• First Intrinsic Anisotropy Observations with the Cosmic Background Imager
• First results from the Very Small Array -- III. The CMB power spectrum
• First results from the Very Small Array -- I. Observational methods
• First results from the Very Small Array -- IV. Cosmological parameter estimation
• The radio source counts at 15 GHz and their implications for cm-wave CMB imaging

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