Mergers of Luminous Early-Type Galaxies

Galaxy mergers play an important role in many astrophysical processes, such as growth of massive galaxies, triggering AGN, formation of supermassive black hole (SMBH) binaries, and gravitational wave (GW) radiation. Merger rate is one of key quantities for these studies. Previous studies show that the pair fraction varies in a range of 1%-10% in the redshift range of z = 0.2-1.2. These merger rates are usually calculated from projected close pairs, and very few previous authors have carefully checked the merging fraction of a large sample of pairs.