High-redshift Lyα emitters: Clues on the Milky Way infancy

Abstract

With the aim of determining if Milky Way (MW) progenitors could be identified as high-redshift Lyman Alpha Emitters (LAEs), we have derived the intrinsic properties of z ≈ 5.7 MW progenitors, which are then used to compute their observed Lyα luminosity, Lα, and equivalent width (EW). MW progenitors visible as LAEs are selected according to the canonical observational criterion, Lα > 1042erg s-1 and EW > 20 Å Progenitors of MW-like galaxies have Lα = 1039-43.25 erg s-1, making some of them visible as LAEs. In any single MW merger tree realization, typically only one (out of ≈ 50) progenitor meets the LAE selection criterion, but the probability of having at least one LAE is very high, P = 68 per cent. The identified LAE stars have ages t* ≈ 150-400 Myr at z ≈ 5.7, with the exception of five small progenitors with t* < 5 Myr and large EW = 60-130 Å LAE MW progenitors provide > 10 per cent of the halo very metal-poor stars [Fe/H] < -2, thus establishing a potentially fruitful link between high-z galaxies and the local Universe. © 2010 The Authors. Journal compilation © 2010 RAS.