The SUPERWIDE Catalog of Wide Binaries

We present the results of our search for wide binaries in the SUPERBLINK high proper motion catalog of 2.8 million stars with proper motions >40 mas/yr, which has been recently enhanced with data from the GAIA mission. In a first step, we conduct a Bayesian analysis taking into account angular separations and proper motion differences provided by the SUPERBLINK catalog, and identify all possible common proper motion (CPM) pairs with separations up to 60 arcminutes. In the second step we expand the analysis using parallaxes from the Gaia DR2 release, and calculate probabilities for each pair to be a gravitationally bound system. The result is a list of ~18,000 pairs with probabilities of being real binaries greater than 99 percent. We show that the distribution of projected physical separations of these wide, field binaries follows a decreasing power law, and shows no evidence of being bimodal, i.e. there is no evidence of a secondary population of pairs with separations $>10^4$ AU. In addition, we find clear evidence that at least 30 percent of these wide binaries are triples/multiples, based on one of the components being over-luminous.