Finding outlier light-curves in catalogs of periodic variable stars

Abstract

We present a methodology to discover outliers in catalogs of periodic light-curves. We use cross-correlation as measure of ``similarity'' between two individual light-curves and then classify light-curves with lowest average ``similarity'' as outliers. We performed the analysis on catalogs of variable stars of known type from the MACHO and OGLE projects and established that our method correctly identifies light-curves that do not belong to those catalogs as outliers. We show how our method can scale to large datasets that will be available in the near future such as those anticipated from Pan-STARRS and LSST.