Galois Families of Modular Forms

Following a joint work with Sara Arias-de-Reyna and François Legrand, we present a new kind of families of modular forms. They come from representations of the absolute Galois group of rational function fields over Q. As a motivation and illustration, we discuss in some details one example: an infinite Galois family of Katz modular forms of weight one in characteristic 7, all members of which are non-liftable. This may be surprising because non-liftability is a feature that one might expect to occur only occasionally.