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The physical properties and evolution of Lyalpha emitting galaxies

A significant fraction of high redshift starburst galaxies presents strong Ly alpha emission. Understanding the nature of these galaxies is important to assess the role they played in the early Universe and to shed light on the relation between the narrow band selected Lyalpha emitters and the Lyman break galaxies: are the Lyalpha emitters a subset of the general LBG population? or do they represent the youngest galaxies in their early phases of formation? We studied a sample of UV continuum selected galaxies from z~2.5 to z~6 (U, B, V and i-dropouts) from the GOODS-South survey, that have been observed spectroscopically. Using the GOODS-MUSIC catalog we investigated their physical properties, such as total masses, ages, SFRs, extinction etc as determined from a spectrophotometric fit to the multi-wavelength (U band to mid-IR) SEDs, and their dependence on the emission line characteristics. In particular we determined the nature of the LBGs with Lyalpha in emission and compared them to the properties of narrow band selected Lyalpha emitters. For U and B-dropouts we also compared the properties of LBGs with and without the Lyalpha emission line.