XDQSO

This value added catalog contains quasar probabilities in three redshift ranges derived using the extreme deconvolution XDQSO technique, as described in Bovy et al. (2011). The quasar probabilities are assigned based on models for the underlying flux distributions of quasars and stars applied to the single-epoch ugriz fluxes of all 160,904,060 point-sources with dereddened i-band magnitude between 17.75 and 22.45 mag in DR8.