Properties of galaxy pairs for the observed galaxy pair catalog properties from Nottale & Chamaraux (2018a) (grey shaded histograms) and galaxy data from the IlustrisTNG-300 simulation. For the latter, the blue histogram corresponds to our base model without velocity errors, and the red histograms are from our full model mimicking apparent magnitude biases and errors on the observed line-of-sight velocity. Left panel: Distribution of galaxy pair members in B-band magnitude M_B. Right panel: Distribution of galaxy pairs in velocity, v, consisting of redshift and peculiar velocity.