  High-contrast peaks in the cosmic microwave background (CMB) anisotropy can
appear as unresolved sources to observers. We fit simulated CMB maps generated
with a cold dark matter model to a set of unresolved features at instrumental
resolution 0.5 degrees to 1.5 degrees and present the integral density per
steradian n(>|T|) of unresolved features brighter than threshold temperature
|T|. A typical medium-scale experiment observing 0.001 sr at 0.5 degree
resolution would expect to observe one unresolved feature brighter than 85 \muK
after convolution with the beam profile, with less than 5% probability to
observe a source brighter than 150 \muK. Increasing the power-law index of
primordial density perturbations n from 1 to 1.5 raises these temperature
limits |T| by a factor of 2. The results are only weakly dependent on the
assumed values of the Hubble constant and baryon density.

Astrophysics