Difference in Dwarf Galaxy Surface Brightness Profiles as a Function of Environment

作者：Lee Youngdae^*; Park Hong Soo; Kim Sang Chul; Moon Dae Sik; Lee Jae Joon; Kim Dong Jin; Cha Sang Mok

来源：Astrophysical Journal, 2018, 859(1): 5.

DOI：10.3847/1538-4357/aabc53

• galaxies: dwarf
• galaxies: evolution
• galaxies: groups: individual (NGC 2784 group)
• galaxies: structure

We investigate surface brightness profiles (SBPs) of dwarf galaxies in field, group, and cluster environments. With deep BVI images from the Korea Microlensing Telescope Network Supernova Program, SBPs of 38 dwarfs in the NGC 2784 group are fitted by a single-exponential or double-exponential model. We find that 53% of the dwarfs are fitted with single-exponential profiles ("Type I"), while 47% of the dwarfs show double-exponential profiles; 37% of all dwarfs have smaller sizes for the outer part than the inner part ("Type II"), while 10% have a larger outer than inner part ("Type III"). We compare these results with those in the field and in the Virgo cluster, where the SBP types of 102 field dwarfs are compiled from a previous study and the SBP types of 375 cluster dwarfs are measured using SDSS r-band images. As a result, the distributions of SBP types are different in the three environments. Common SBP types for the field, the NGC 2784 group, and the Virgo cluster are Type II, Type I and II, and Type I and III profiles, respectively. After comparing the sizes of dwarfs in different environments, we suggest that since the sizes of some dwarfs are changed due to environmental effects, SBP types are capable of being transformed and the distributions of SBP types in the three environments are different. We discuss possible environmental mechanisms for the transformation of SBP types.

• 出版日期2018-5-20