The Effects of Environment on Galaxy Evolution in Mapping Nearby Galaxies at Apache Point Observatory (MaNGA)

Abstract

Galaxy interactions and mergers are known to have been a fundamental process in the hierarchical formation of the Universe. These galaxy interactions first occurred between low-mass galaxies, analogous to today's dwarf galaxies. There have been a lack of studies on dwarf-dwarf galaxy interactions due to the difficulties in observing them. The development of better technology and telescopes has allowed the field to begin to gather the much-needed information on these events. This pilot study represents the first to examine the effects of dwarf-dwarf galaxy interactions on star-formation enhancement and star-formation rates using spatially and spectroscopically resolved data from the SDSS-IV MaNGA Survey. Two samples are studied to this effect: a sample of nine dwarf galaxies known to have close dwarf companions and a sample of fifteen dwarf galaxies known to be extremely isolated (~ 1 Mpc) from any other galaxies. The ionization conditions of each galaxy is studied using diagnostic diagrams which can classify regions within the galaxy as star-forming. The percentage of surface area which is star-forming and the central star-formation rate is calculated for each galaxy in both samples. We find that star formation is enhanced by almost a factor of four within the galaxies in the paired sample compared to those in the isolated sample. The methods developed for this study can be applied to much larger samples in the future once the data become available, thus allowing for further study of these crucial dwarf-dwarf galaxy interactions.