The Bulletin of The Korean Astronomical Society (천문학회보)

The Korean Astronomical Society (한국천문학회)
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ALMA/ACA CO (1-0) observations of group galaxies

  • Lee, Bumhyun (Kavli Institute for Astronomy and Astrophysics, Peking University) ;
  • Wang, Jing (Kavli Institute for Astronomy and Astrophysics, Peking University) ;
  • Chung, Aeree (Department of Astronomy, Yonsei University) ;
  • Ho, Luis C. (Kavli Institute for Astronomy and Astrophysics, Peking University) ;
  • Wang, Ran (Kavli Institute for Astronomy and Astrophysics, Peking University) ;
  • Shao, Li (National Astronomical Observatories, Chinese Academy of Sciences) ;
  • Michiyama, Tomonari (Kavli Institute for Astronomy and Astrophysics, Peking University) ;
  • Wang, Shun (Kavli Institute for Astronomy and Astrophysics, Peking University) ;
  • Peng, Eric W. (Kavli Institute for Astronomy and Astrophysics, Peking University) ;
  • Kilborn, Virginia (Centre for Astrophysics and Supercomputing, Swinburne University of Technology)
  • Published : 2020.10.13
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Abstract

Galaxy groups are the place where many galaxies feel the impact of the surroundings (e.g., merging, tidal interaction, ram pressure stripping) before joining bigger structures like (sub)clusters. A significant fraction of galaxies is quenched in the group environment. Such "pre-processing" of galaxies in groups is likely to affect galaxy evolution tremendously. To better understand how environmental processes in galaxy groups affect molecular gas, star formation activity, and galaxy evolution, we carried out CO imaging observations of group galaxies, using the Atacama Compact Array (ALMA/ACA). We selected all the targets that have been detected in the GEMS-HI survey for two groups, making the sample of 40 galaxies (18 galaxies in IC 1459 group and 22 galaxies in NGC 4636 group). Our ALMA/ACA observation is the first CO imaging survey for two groups. In this work, we present CO images of group galaxies, together with their star formation maps and HI images. Our ACA CO data show the asymmetric distribution of molecular gas in some of our samples. We discuss the impact of the group environment on molecular gas and star formation activity.

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