Washington: New research from NASA`s Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) has found that, contrary to previous theories, gargantuan galaxies appear to slow their growth over time, feeding less and less off neighbouring galaxies.
"We`ve found that these massive galaxies may have started a diet in the last 5 billion years, and therefore have not gained much weight lately," Yen-Ting Lin of the Academia Sinica in Taipei, Taiwan, lead author of the study, said.
Peter Eisenhardt, a co-author from NASA`s Jet Propulsion Laboratory in Pasadena, Calif., said, "WISE and Spitzer are letting us see that there is a lot we do understand-but also a lot we don`t understand-about the mass of the most massive galaxies."
Eisenhardt identified the sample of galaxy clusters studied by Spitzer, and is the project scientist for WISE.
The new findings will help researchers understand how galaxy clusters-among the most massive structures in our universe-form and evolve.
Galaxy clusters are made up of thousands of galaxies, gathered around their biggest member, what astronomers call the brightest cluster galaxy, or BCG.
BCGs can be up to dozens of times the mass of galaxies like our own Milky Way.
They plump up in size by cannibalizing other galaxies, as well as assimilating stars that are funneled into the middle of a growing cluster.
The study is published in the Astrophysical Journal.