---
author:
- 'L.Pentericci'
- 'A. Grazian'
- 'C. Scarlata'
- 'A. Fontana  '
- 'M. Castellano'
- 'E. Giallongo'
- 'E. Vanzella'
title: 'Physical and morphological properties of z$\sim 3$ LBGs: dependence on Ly$\alpha$ line emission '
---

Introduction
============

A long debated issue concerns the relation between Lyman break galaxies (LBGs), i.e. star-forming galaxies selected from the presence of the Lyman break in their spectral energy distribution (e.g. Steidel et al. 1996), and Ly$\alpha$ emitters (LAEs), i.e. star-forming galaxies selected via the presence of a strong  emission line, through deep narrow-band observations (e.g Cowie & Hu 1998, Hu et al. 1998, Rhoads & Malhotra 2001). Both these techniques have led to the discovery of large number of galaxies at increasingly high redshift (e.g. Ouchi et al. 2005, Venemans et al. 2007, Stanway et al. 2007, Ota et al. 2008), with the current record holder being a LAE at z=6.96 (Iye et al. 2006). The nature of the high redshift galaxies selected through the  emission line and the link with the star-forming population selected via the Lyman–Break is still not clear (e.g., [@gaw09]). This relation has an important implication in our interpretation of the very high redshift Universe where, 