SIMBAD references

We selected 40 candidate Lyα-emitting galaxies (LAEs) at z≃3.1 with observed-frame equivalent widths greater than 150 Å and inferred emission-line fluxes above 2.5x10^–17 ergs/cm2/s from deep narrowband and broadband MUSYC images of the Extended Chandra Deep Field South. Covering 992 arcmin², this is the largest ``blank field'' surveyed for LAEs at z∼3, allowing an improved estimate of the space density of this population of (3±1)x10^–4 h³₇₀/Mpc3. Spectroscopic follow-up of 23 candidates yielded 18 redshifts, all at z≃3.1. Over 80% of the LAEs are dimmer in continuum magnitude than the typical Lyman break galaxy (LBG) spectroscopic limit of R=25.5 (AB), with a median continuum magnitude R≃27 and very blue continuum colors, V-z≃ 0. Over 80% of the LAEs have the right UVR colors to be selected as LBGs, but only 10% also have R≤25.5. Stacking the UBVRIzJK fluxes reveals that LAEs have stellar masses ≃5x10⁸ h^–2₇₀M_☉and minimal dust extinction, A_V≲0.1. Inferred star formation rates are ≃6 h^–2₇₀M_☉/yr, yielding a cosmic star formation rate density of 2x10^–3 h₇₀M_☉/yr/Mpc3. None of our LAE candidates show evidence for rest-frame emission-line equivalent widths EW_rest>240 Å that might imply a nonstandard initial mass function. One candidate is detected by Chandra, implying an AGN fraction of 2%±2% for LAE candidate samples. In summary, LAEs at z∼3 have rapid star formation, low stellar mass, little dust obscuration, and no evidence for a substantial AGN component.