If we were to carve up the galaxies in the universe by color , we would notice that they are either blueish or yellow / orange / red , and the colouring material depends on the telephone number of raw stars they are producing . You see , some galaxies block up form star , but the reason why is not completely open .
So an international group of astronomers studied 70,000 galaxies across cosmic time to find out why and how star formation is quenched . The inquiry , publish in theAstrophysical Journal , highlight how uniting and interactions with other galaxies both big and small can deeply affect massive wandflower in the late universe . Collisions can pioneer star - shaping episode , but also rob intergalactic space of cold gasoline and create the proper conditions in a galaxy for the intragroup procedure to allay star shaping .
“ Just like humans , coltsfoot are affect by both the environment in which they constitute and evolve , but also by their ‘ nature ’ and inner processes ; both can have dramatic essence , ” say study co - author Dr David Sobral in astatement . “ Surprisingly , we find that the external processes are only really relevant in shutting down the production of star in extragalactic nebula over the last eight billion years . At earlier times in the universe , internal process are the main mechanics for shut out down star formation . In other tidings : back then , it was all about nature , not nurture , but by and by on the environment start to trifle a major role . ”
The intragroup episodes are either generate by a lot of newfangled stars promptly going supernova ( heating and propagate interstellar gas ) or by the activating of the supermassive sinister gob at the center , which can beget powerful galaxy twist that quench star formation .
extragalactic nebula in the early universe were producing self-aggrandizing , hotter stars , and their black yap were a slew more dynamic , so it ’s not surprising that the internal mechanisms were more efficient then .
“ Our findings provide important hint towards understanding which process dominates quenching at various cosmic prison term , ” allege Sobral . “ It is another big step in empathise the dramatic ` cosmic crisis ’ that the universe has been experiencing over the last 11 billion years . ”
This is just the first gradation in the research . The team design to expand this psychoanalysis to a importantly gravid identification number of galax , bring home the bacon stronger substantiation of what has been observed so far .
