Distribution of the beta parameter of the detected simulated extended sources. The shades show the detected sources in the “Confusion” run, with shades of grey illustrating the overlap of sources. The dashed and solid lines show the location of 90% and 50% detection completeness level. The value of beta is uniquely determined by the mass and redshift of the halo, using the tabulations of Finoguenov et al. (2007).