SALT and SDSS redshifts for each pair.

  -- ----------- ------------ ------------- --------------------- --
                                                                  
                                                                  
         BCG      190.404850   $-$0.668280   $0.4587 \pm 0.0001$  
      Companion   190.406416   $-$0.667039            —           
         BCG      128.317079    0.108010              —           
      Companion   128.316370    0.108480     $0.4748 \pm 0.0001$  
         BCG      153.259460    0.812003     $0.4063 \pm 0.0001$  
      Companion   153.259030    0.809660              —           
         BCG      27.261019    $-$0.639814   $0.3584 \pm 0.0001$  
      Companion   27.261605    $-$0.639844            —           
         BCG      346.949880    0.948270     $0.3686 \pm 0.0001$  
      Companion   346.949133    0.947189              —           
         BCG      186.754036    0.765942              —           
      Companion   186.753290    0.767780     $0.5153 \pm 0.0002$  
         BCG      148.316850    1.272180     $0.3648 \pm 0.0001$  
      Companion   148.316048    1.272079              —           
         BCG      206.032182    1.948250              —           
      Companion   206.031830    1.948720     $0.5432 \pm 0.0001$  
         BCG      223.098640    0.949810     $0.4830 \pm 0.0001$  
      Companion   223.099826    0.950909              —           
         BCG      210.260650    0.275680              —           
      Companion   210.258767    0.275656     $0.4757 \pm 0.0001$  
         BCG      218.763280    3.109750     $0.3829 \pm 0.0001$  
      Companion   218.763793    3.111125              —           
         BCG      357.091165    0.741055              —           
      Companion   357.088710    0.741300     $0.4113 \pm 0.0001$  
  -- ----------- ------------ ------------- --------------------- --

Method - The pair fraction and merger-inferred stellar mass growth of the BCGs {#sec:method}
==============================================================================

Constructing an evolutionary cluster sequence {#sec:evol_seq_clusters}
---------------------------------------------

The stellar masses of BCGs are known to correlate with the halo masses of their host clusters, with more massive halos hosting more massive BCGs [e.g. @Edge1991; @Burke2000; @Brough2008; @Stott2008; @Stott2010; @Stott2012; @Whiley2008; @Collins2009; @Hansen2009; @Lidman2012]. Consequently, it is 