The previously hidden origins of quasars, energetic galaxies that are hailed as the brightest objects in the universe, has been unveiled by the Hubble Space Telescope. According to observations in near-infrared wavelengths, it’s likely to be down to galaxies crashing into each other – something that has been suspected for some time.
“Hubble images confirm that the most luminous quasars in the universe result from violent mergers between galaxies, which fuels black hole growth and transforms the host galaxies,” explains Megan Urry, an astrophysicist at Yale University. “Those mergers are also sites of future black hole mergers, which we hope will one day be visible with gravitational wave telescopes.”
Quasars are so bright that they emit light that matches the luminosity of one trillion stars. Over the past two decades astronomers have concluded that these active galaxies get their power from the insatiable appetite of the supermassive black holes that rest at their centres alone but it seems that there is much more action involved – particularly in the early universe.
“The Hubble observations are telling us that the peak of quasar activity in the early universe is driven by galaxies colliding and merging together,” says lead scientist Eilat Glikman of Middlebury College in Vermont, United States. “We are seeing the quasars in their teenage years, when they are growing quickly and all messed up.”