this.

In this paper we investigate the importance of major mergers in the stellar mass build-up of BCGs between $0.08 \leq z \leq 0.50$. We select BCGs from a photometric cluster catalogue, which has been constructed from the Sloan Digital Sky Survey [SDSS; @York2000]. We use spectroscopic information from the SDSS to identify which BCGs and nearby companions are potential major merger candidates. The close pair fraction is used as a proxy for the merger fraction to determine how much stellar mass growth the BCGs will experience due to mergers.

This paper is structured as follows. Section \[sec:sample\_descr\] contains details pertaining to the redMaPPer catalogue; in Section \[sec:method\] the methods are described. The results on the pair fraction and merger-inferred stellar mass growth of the BCGs are shown and discussed in Section \[sec:results\_disc\]. Conclusions are drawn in Section \[sec:concl\]. Throughout the paper we assume a flat $\Lambda$CDM cosmology with $\Omega_{M} = 1 - \Omega_{\Lambda} = 0.3$ and $H_{0} = 70$ [kms$^{-1}$Mpc$^{-1}$]{}. Magnitudes are given in the AB system and the [@Chabrier2003] initial mass function is used.

Data {#sec:sample_descr}
====

Overview of the redMaPPer cluster catalogue {#sec:redM_over}
-------------------------------------------

Throughout this paper we use version 5.2 of the red-sequence Matched-filter Probabilistic Percolation 