Ever seen a snapshot of the universe and wondered just how and what makes the beautiful swirling shapes that modern telescopes now let us see? Imagery of the Horsehead Nebula, the Pillars of Creation, and even the Rose Galaxies have captivated researchers and the public for decades, but finding exactly what causes space dust, planets and stars to conform in such elegant forms has often eluded astronomers studying the infinite wonders of space. But a new study conducted by researchers with the Harvard University Smithsonian Center for Astrophysics (CfA) reveals that the connection between collections of stars and the elliptical shapes of galaxies may have something to do with dark matter and the presence of black holes at the center of every galactic mass.
Designed to address controversy within the field of astronomy, the new study published in the Astrophysical Journal investigates in particular elliptical galaxies to provide new insights on how a galaxy interacts with that black hole at the center of its cluster. And the researchers find that the invisible hand of dark matter may have something to do with how such small black holes can have such great of a pull.
"There seems to be a mysterious link between the amount of dark matter a galaxy holds and the size of its central black hole, even though the two operate on vastly different scales" lead researcher, Akos Bogdan says.
To investigate the link between dark-matter halos and supermassive black holes, the researchers studied more that 3,000 elliptical galaxies. Star motions were used to trace and weigh the galaxies' central black holes, and x-ray measurements of hot gas surrounding the galaxies was used as a proxy to help estimate the weight of their dark-matter halos. And what the researchers found was a much stronger correlation between the mass of the dark-matter halos and the mass of the black holes than what they had ever estimated before.
By revealing the strong relationship, which far outweighs the the relationship between black holes an a galaxy's stars alone, the researchers were able to find a connection that likely guides the growth and formation of the elliptical galaxies themselves. And it's something that they believe, may uncover some cosmic order in a universe presumed to be created out of chaos.
"In effect" Bodan says, "the act of merging creates a gravitational blueprint that the galaxy, the stars, and the black hole will follow in order to build themselves."