Abstract
We present results of radiative transfer calculations to measure the impact of gas bulk rotation on the morphology of the Lyman α line in galaxies. We model a galaxy as a sphere with a homogeneous mixture of dust and hydrogen at a constant temperature. These spheres have a solid-body rotation with maximum velocities in the range 0-300 km s^{-1} and neutral hydrogen optical depths in the range τ_{H}=10^{5}-10^{7}. We also consider two kinds of spatial distribution for the radiation sources with respect to the sphere: central and homogeneous. We find that the line width and the intensity at the line's center increases with rotational velocity. In the case of homogeneously distributed sources, for large rotational velocities the line transforms from a double peak to a single peak at the line center. Under the same conditions the escape fraction increases ∼ 30%. For radiation sources located off-center, the line morphology presents a range of single, double and triple peaked lines. We show how these results are useful to interpret recent spectroscopic results of distant z∼ 2-3 star forming galaxies.
