Active and dust obscured star-forming galaxies at z ∼ 4 probed with UV spectral slope beta

We investigate the stellar population of star-forming galaxies at z ∼ 4 by focusing on their slope of rest-frame ultraviolet continuum called UV spectral slope β. We analyze the sample of bright Lyman Break Galaxies (LBGs) with Subaru/i'≤26.0in the Subaru/XMM-Newton Deep Survey field. Our detailed SED fitting analysis indicates that the LBGs with observed UV slope > -1.7, , Av > 1.0, and intrinsic UV slope < -2.5 are the intrinsically active star-forming galaxies with star formation rates larger than a few × 10² M_⊙yr^-1. A significant fraction of the UV-selected LBGs at z ∼ 4 is on-going active and dust obscured star-forming galaxies.