[eng] Empirical studies such as Goyal et al. (J Polit Econ 114(2):403-412, 2006) or Newman (Proc Natl Acad Sci USA 101(Suppl. 1):5200-5205, 2004) show that scientific collaboration networks present a highly unequal and hierarchical distribution of links. This implies that some researchers can be much more active and productive than others and, consequently, they can enjoy a much better scientific reputation. One may think that big intrinsical differences among researchers can constitute the main driving force behind these inequalities. Nevertheless, this model shows that, under specific circumstances, very similar individuals may self-organize themselves forming unequal and hierarchical structures.