We simulate the evolution of halo wide binaries in the presence of the massive compact halo objects (MACHOs) and compare our results to the sample of wide binaries in a companion paper. The observed distribution is well fitted by a single power law for angular separations, 3 5 < Δθ < 900'', whereas the simulated distributions show a break in the power law whose location depends on the MACHO mass and density. This allows us to place upper limits on the density of MACHOs as a function of their assumed mass. At the 95% confidence level, we exclude MACHOs with masses M > 43 M ☉ at the standard local halo density ρ H . This all but removes the last permitted window for a full MACHO halo for masses M > 10 -7.5 M ☉ .
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A 2004 study studied this question.