Stellar mass evolution of a merger pair. The solid black line and dashed black line represent the mass growth of the main galaxy and satellite galaxy, respectively. The three horizontal lines mark the definition of main galaxy mass (M_{*, main}), satellite galaxy mass (M_{*, sat}), and remnant galaxy mass (M_{*,+1 Gyr}). The three gray vertical lines represent the merger time (t_merger), 1 Gyr before (t_merger−1 Gyr), and 1 Gyr after (t_merger+1 Gyr) the merger.