A Surprising Alignment of Quasars Across the Universe

Artist’s impression of mysterious alignment of quasar rotation

Artist’s conception of the alignment of quasars over the vast filaments that are home to galaxy clusters spread across billions of light years (credit: European Southern Observatory)

In a remarkable discovery, astronomers using ESO’s Very Large Telescope (VLT) in Chile have discovered that quasars separated by billions of light years are aligned parallel to each other, as if they were under the influence of an unseen mechanism that gets them pointing in the same direction. This mechanism seems to be related to the largest-scale structures in the universe, the vast filaments of galaxy clusters that form around voids and bubbles were very few galaxies are found.

A quasar is a galaxy with a supermassive black hole at its center. The black hole sucks in material which creates a spinning disk with an enormously bright jet along the axis of rotation. A quasar generates so much energy, it outshines all the rest of the stars of its host galaxy combined. Were a quasar placed at the same distance as the star Vega, about 26 light years from us, it would shine as brightly as the Sun.

You don’t see many quasars in our part of the universe any more. But they were quite common in the first several billion years of the life of the universe. Which means the quasars we see with big telescopes must be quite distant because it took their ancient light billions of years to reach us.

The light from the 93 quasars measured in the ESO survey left when the universe was 1/3 of its present age. The quasars were too far and faint to reveal their jets directly. But astronomers measured the polarization of the light, which is related to the direction of rotation, and found 19 of the quasars were pointing more or less in the same direction, the direction that points along the filaments themselves (see image above). The probability that these are chance alignments is less than 1%.

Some models of the large-scale structure of the universe predict a degree of alignment. But this study, which is the first to confirm this prediction, shows the effect on a much larger scale. So astronomers have a new puzzle on their hands as they wrestle with what causes the alignment of these energetic galaxies over billions of light years.

Job security for scientists may suffer the whims of funding agencies. But there are always new questions to answer as astronomers observe the universe on its largest scale.