Modeling the Radial Abundance Distribution of the Transition Galaxy NGC 1313

NGC 1313 is the most massive disk galaxy showing a flat radial abundancedistribution in its interstellar gas, a behavior generally observed inmagellanic and irregular galaxies. We have attempted to reproduce this flatabundance distribution using a multiphase chemical evolution model, which hasbeen previously used sucessfully to depict other spiral galaxies along theHubble morphological sequence. We found that it is not possible to reproducethe flat radial abundance distribution in NGC 1313, and at the same time, beconsistent with observed radial distributions of other key parameters such thesurface gas density and star formation profiles. We conclude that a morecomplicated galactic evolution model including radial flows, and possibly massloss due to supernova explosions and winds, is necessary to explain theapparent chemical uniformity of the disk of NGC 1313Comment: 14 paginas, 4 figures, to be published in ApJ, apri