Contribution of bright extragalactic radio sources to microwave anisotropy

We estimate the contribution of extragalactic radio sources to fluctuations in sky temperature over the range of frequencies (10-300 GHz) used for cos mic microwave background (CMB) anisotropy measurements. CMB anisotropy obse rvations at high resolution and low frequencies are especially sensitive to this foreground. Our catalog of 2207 bright radio sources includes 758 sou rces with flux measurements at 90 GHz. We develop a method to extrapolate t he source spectra and predict skymaps of extragalactic radio sources at ins trument resolutions of 10'-10 degrees FWHM. Our results indicate that the b rightest radio sources will dominate microwave anisotropy for a wide range of resolutions and frequencies. We predict the location and flux of the bri ghtest radio sources at each frequency, making it straightforward to develo p a template for masking the pixels containing them. This masking should be sufficient to protect most CMB anisotropy observations from unacceptable r adio source confusion.