High redshift Lya emitters: clues on the Milky Way infancy

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 Ly lumi- nosity, L, and equivalent width, EW. MW progenitors visible as LAEs are selected according to the canonical observational criterion, L > 1042 erg s−1 and EW > 20 °A . P r o g e n i t o r s o f M W - l i k e g a l a x i e s h a v e L = 1 0 39−43.25 e r g s − 1 , m a k i n g s o m e o f them visible as LAEs. In any single MW merger tree realization, typically only 1 (out of 50) progenitor meets the LAE selection criterion, but the probability to have at least one LAE is very high, P = 68%. 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 °A. LAE MW progenitors provide > 10% of the halo very metal-poor stars [Fe/H]< −2, thus establishing a potentially fruitful link between high-z galaxies and the Local Universe.