Nearby ULX in metal-poor environment as cosmological laboratories

Super-massive black holes (SMBHs) at redshift z>7 pose a serious challengeto our understanding of black hole (BH) formation and evolution. Mostlikely SMBHs at high redshift require massive seed black holes (BHs) (10^5solar masses) created in the gravitational collapse of large gas cloudswith subsequent merging. We propose to observe 5 extreme metal-poor bluecompact dwarf galaxies, which are the best (local) laboratory for massiveBH seed formation and star formation under low metallicity conditions.