Modeling the Radial Abundance Distribution of the Transition Galaxy NGC 1313

Abstract

NGC 1313 is the most massive disk galaxy showing a Ñat radial abundance distribution in its inter-stellar gas, a behavior generally observed in Magellanic and irregular galaxies. We have attempted to reproduce this Ñat abundance distribution using a multiphase chemical evolution model, which has been previously used successfully to depict other spiral galaxies along the Hubble morphological sequence. We found that it is not possible to reproduce the Ñat radial abundance distribution in NGC 1313 and at the same time be consistent with observed radial distributions of other key parameters, such as the surface gas density and star formation proÐles. We conclude that a more complicated galactic evolution model, including radial Ñows and possibly mass loss due to supernova explosions and winds, is necessary to explain the apparent chemical uniformity of the disk of NGC 1313.