The answer: by the dual dumbbell black hole capacity to create and focus gas into the middle, pressure cooker alike to form "Cannonball galaxies" (A) see below.
Later however these Cannonball galaxies create smaller supernova black holes forming  systems like Herbig Haro (HH) systems (B) with a decreasing CENTRAL focused  pressure cooker effect and less effective central star formation.. 
HH systems are supposed to be based on the strange capacity of equal sized black holes to form a dumbbell topology with star forming in between. 
See also: 
Galaxy’s rapid growth spurt may have spawned 3000 suns per year.
see: https://www.newscientist.com/article/2115501-galaxys-rapid-growth-spurt-may-have-spawned-3000-suns-per-year/#.WEhyu8F0fpM.twitter 
Quotation: "How do they get enough fuel to form stars so rapidly? " because all early galaxies feel the singular extra influence of the dual GABHs Galaxy Anchor Black Holes, splitted from the big bang BH.
Quotation: "How do they get enough fuel to form stars so rapidly? " because all early galaxies feel the singular extra influence of the dual GABHs Galaxy Anchor Black Holes, splitted from the big bang BH.
Example of small scale black hole splitting in the Spire part 










