How did the peculiar S0 galaxy M85 form?

  • Ko, Youkyung (Department of Physics and Astronomy, Seoul National University) ;
  • Lee, Myung Gyoon (Department of Physics and Astronomy, Seoul National University) ;
  • Sohn, Jubee (Department of Physics and Astronomy, Seoul National University) ;
  • Ryu, Jinhyuk (Department of Physics and Astronomy, Seoul National University) ;
  • Jang, In Sung (Department of Physics and Astronomy, Seoul National University) ;
  • Lim, Sungsoon (Department of Astronomy, Peking University) ;
  • Park, Hong Soo (Korea Astronomy and Space Science Institute) ;
  • Hwang, Narae (Korea Astronomy and Space Science Institute) ;
  • Park, Byeong-Gon (Korea Astronomy and Space Science Institute)
  • Published : 2015.04.10

Abstract

M85 is a merger remnant galaxy in the Virgo Cluster, showing complex merging features. Globular clusters in M85 are a good tracer of its merging history. To investigate globular cluster system of M85, we obtain deep and wide field images of M85 in ugi filters covering one square degree using CFHT/MegaCam. We discover about 1,000 globular cluster candidates in these images. The color distribution of the globular cluster candidates within r < 5' from M85 does not show a clear bimodality and blue globular cluster candidates are more than red ones. These features are different from those in massive early-type galaxies. The spatial distribution of the globular cluster candidates is elongated along the faint stellar light of M85. We also investigate the spatial distribution of sub-populations of the globular cluster candidates with different color and brightness and estimate their ages based on their color. We discuss these results in relation with the formation history of M85.

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