Contribution of Bright Extragalactic Radio Sources to Microwave Anisotropy

We estimate the contribution of extragalactic radio sources to fluctuationsin sky temperature over the range of frequencies (10-300 GHz) used for CosmicMicrowave Background (CMB) anisotropy measurements. CMB anisotropy observationsat high resolution and low frequencies are especially sensitive to thisforeground. We have compiled a catalog of 2207 bright radio sources, including758 sources with flux measurements at 90 GHz. We develop a method toextrapolate the source spectra and predict skymaps of extragalactic radiosources at instrument resolutions of 10 arcmin to 10 degrees FWHM. Our resultsindicate that the brightest sources will dominate microwave anisotropy for awide range of resolutions and frequencies. Our skymaps predict the location andflux of the brightest radio sources at each frequency, making itstraightforward to develop a template for masking the pixels containing them.This masking should be sufficient to protect high resolution CMB anisotropyobservations from unacceptable radio source confusion.