2000/02/24 by R. Subrahmanyan, M. J. Kesteven, R. D. Ekers +4 · 1 citation
Physics and Astronomy · #Anisotropy #Astronomy #Astrophysics #Background radiation #Brightness #Brightness temperature #Cosmic microwave background #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Image (mathematics) #Noise (video) #Optics #Physics #Radiation #Radio Astronomy Observations and Technology #Sky #South Pole Telescope #Telescope #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.2000.03444.x
published as Mon.Not.Roy.Astron.Soc. 315 (2000) 808 · 17 pages, includes 8 figures and 6 tables, accepted for publication in MNRAS
arxiv created 2000/02/24 · openalex publication_date 2000/07/11 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We have surveyed six distinct ‘empty fields’ using the Australia Telescope Compact Array (ATCA) in an ultracompact configuration with the aim of imaging, with a high brightness sensitivity, any arcminute-scale brightness-temperature anisotropies in the background radio sky. The six well-separated regions were observed at a frequency of 8.7 GHz, and the survey regions were limited by the ATCA primary beams which have a full width at half-maximum of 6 arcmin at this frequency; all fields were observed with a resolution of 2 arcmin and an rms thermal noise of 24 λJy beam−1. After subtracting foreground confusion detected in higher resolution images of the fields, residual fluctuations in Stokes I images are consistent with the expectations from thermal noise and weaker (unidentified) foreground sources; the Stokes Q and U images are consistent with expectations from thermal noise. Within the sensitivity of our observations, we have no reason to believe that there are any Sunyaev-Zeldovich holes in the microwave sky surveyed. Assuming Gaussian-form CMB anisotropy with a ‘flat’ spectrum, we derive 95 per cent confidence upper limits of Qflat<10-11 λK in polarized intensity and Qflat<25 λK in total intensity. The ATCA filter function peaks at l=4700 and has half-maximum values at l=3350 and 6050.