Program: GN-2015A-Q-207

Merger remnant galaxies are an ideal laboratory to study the formation of massive early-type galaxies because they show on-going process of merging events. M85 is one of the famous merger remnants in the northern part of the Virgo Cluster, being a peculiar S0 galaxy showing distinct shell structures. Several observational studies based on photometric data suggested that it experienced a merger about 2 Gyr ago. Recently we detected more than 1,000 globular cluster candidates in one square degree field of M85 using CFHT/MegaCam ugi-band images. They show a spatial distribution elongated along diffuse halo stellar light of M85, with an angle of 45 degree to the bulge. It is considered to be associated with merging events. If so, it is expected that a significant fraction of the globular clusters may be 2 Gyr old. We propose a spectroscopic survey of about 100 bright globular cluster candidates of M85 with GMOS at Gemini North in multi-slit mode. Main goals are 1) to measure the radial velocity of globular cluster candidates and confirm their members, 2) to derive their age and metallicity, and find any intermediate-age globular clusters which may be the remnant of merging, and 3) to derive the mass profile of M85 and trace its dark matter content.