JUNE 18, 2015

Quasars are the light fantastic. They are the brightest beacons in the universe, blazing across space with the intrinsic brightness of one trillion suns. Yet the objects are not vast galaxies, but they appear as pinpoint sources in the biggest telescopes of today — hence the term "quasar" for quasi-stellar object. Discovered in the 1960s, it took more than two decades of research to come to the conclusion that quasars are produced by the gusher of energy coming from over-fed supermassive black holes inside the cores of very distant galaxies. And, most quasars bloomed into a brief existence 12 billion years ago.
The big question has been, why? What was happening in the universe 12 billion years ago? The universe was smaller and so crowded that galaxies collided with each other much more frequently than today. Astronomers using Hubble's near-infrared vision tested this hypothesis by looking at dusty quasars where their glow was suppressed by dust, allowing a view of the quasar's surroundings. Hubble's sharp vision revealed chaotic collisions between galaxies that gave birth to quasars by fueling a supermassive central black hole.

ABOUT THIS IMAGE:
[Top Row] This is a selection of photos from a Hubble Space Telescope survey of 11 ultra-bright quasars that existed at the peak of the universe's star-formation era, which was 12 billion years ago. The quasars (powered by supermassive black holes) are so compact and bright they make a diffraction-spike pattern in the telescope's optics — an optical artifact typically only produced by bright nearby stars. Despite their brightness, the quasars are actually dimmed by dusty gas around them. The infrared capability of Hubble's Wide Field Camera 3 was able to probe deeply into the material around the quasars.
[Bottom Row] When the glare of the quasar is subtracted, researchers see evidence for collisions between galaxies. The collisions and mergers gave birth to the quasars by fueling the supermassive black hole at the core of the galaxies. The new images capture the dust-clearing transitional phase in the merger-driven quasar birth. These observations show that the brightest quasars in the universe live in merging galaxies.