Ultraviolet Dust Grain Properties in Starburst Galaxies: Evidence from Radiative Transfer Modeling and Local Group Extinction Curves

摘要

This paper summarizes the evidence of the ultraviolet properties of dustgrains found in starburst galaxies. Observations of starburst galaxies clearlyshow that the 2175 A feature is weak or absent. This can be the result ofradiative transfer effects (mixing the dust and stars) or due to dust grainswhich do not have this feature. Spherical DIRTY radiative transfer models implythat it is not radiative transfer effects, but other radiative transfer modelswith disk/bulge geometries have found cases where it could be radiativetransfer effects. Recent work on the extinction curves in the Magellanic Cloudsand Milky Way has revealed that the traditional explanation of low metallicityfor the absence of the 2175 A feature in the Small Magellanic Cloud is likelyincorrect. The SMC has one sightline with a 2175 A feature and the Milky Wayhas sightlines without this feature. In addition, where the 2175 A feature isfound to be weak or absent in both Magellanic Clouds and the Milky Way, thereis evidence for recent star formation. Taking the sum of the radiative transfermodeling of starburst galaxies and the behavior of Local Group extinctioncurves, it is likely that the dust grains in starburst galaxies intrinsicallylack the 2175 A feature.