Observational evidence for a different IMF in the early Galaxy
  The unexpected high incidence of carbon-enhanced, s-process enriched unevolved stars amongst extremely metal-poor stars in the halo provides a significant constraint on the Initial Mass Function (IMF) in the early Galaxy. We argue that these objects are evidence for the past existence of a large population of intermediate-mass stars, and conclude that the IMF in the early Galaxy was different from the present, and shifted toward higher masses. 
Sara Lucatello (1,2), Raffaele G. Gratton (1), Timothy C. Beers (3),   Eugenio Carretta (1,4) (1- INAF OAPD; 2- Dipartimento...