Lyman-alpha radiation transfer in simulated galaxies : variation of Lya escape fraction, spectra, and images with viewing angle, for different galaxy formation scenarios

We present our first results from a study of Lyman-alpha (hereafter lya) radiation transfer calculations in a simulated dwarf galaxy (M_{halo}=10^{10} M_{sun}) isolated in its dark matter halo. For two different galaxy formation senarios, we discuss the variation of the lya spectra, images and escape fractions with the line of sight. In the case of star-formation with supernova feedback, the lya emergent spectra are different edge-on and face-on, whereas they are identical in all directions in the simulation without supernova feedback. In particular, the lya beam is collimated along the rotation axis in the case with feedback, leading to double the lya equivalent width compared to the intrinsic emission. The lya escape fraction depends more strongly on the assumptions concerning the star formation (feedback or not), than on the different lines of sight for one given simulation.