The bizarre alignment of the quasars
No, this is not Voyager or Kazzenger. It is ESO, the European Southern Observatory. Even if the title looks proper to Voyager, it seems that there is not the belt of Orion, nor the pyramids of Egypt: it’s a bizarre alignment of quasars at distances of billions of light years.
To begin with, it is perhaps necessary to explain what a quasar is: it is a far away galaxy (more or less in the early phase of the universe) with an active central black hole, an active galactic nucleus (AGN), a AGN, capable of producing a light so strong to obscure.
The quasars, which have a proper motion close to zero, are used to determine the cosmological distances. Now, researchers from Belgium, using data from the Very Large Telescope have found a strange fact.
A team led by Damien Hutsemékers at the University of Liège in Belgium used the FORS instrument mounted on the VLT to study 93 quasars that form a large group that is spread over billions of light years away, given at a time when the Universe had about one-third of its present age.
“The first odd thing we noticed was that some of the axes of rotation of the quasar were aligned with each other – in spite of these quasars are separated by billions of light years,” said Hutsemékers.
The team then sought to better understand and verify whether these rotation axes were linked not only with each other but also to the large-scale structure of the Universe at the time of the cosmos.
The distribution of galaxies on scales of billions of light years says that these are not distributed evenly. They form instead a cosmic web of filaments and clumps around huge voids where the galaxies are rare. An arrangement known as the large-scale structure.
But the new results of the VLT indicate that the axis of rotation of the quasar tends to be parallel to the large scale structures to which they belong, and researchers estimate that the probability that these alignments are random is less than 1%.
“A correlation between the orientation of quasars and the structure they belong to is an important prediction of numerical models of evolution of our Universe. Our data provide the first observational confirmation of this effect, on scales much larger than what had been observed to date for normal galaxies,” adds Dominique Sluse of the Argelander-Institut für Astronomie in Bonn, Germany and University of Liège.
The rotation axes or the jets of the quasars could not be seen directly by the scientists. Instead they calculated the polarization of the light from each quasar. For 19 quasars, the team found a considerably polarized signal. The path of this polarization, linked with other figures, could be used to presume the angle of the accretion disc and in future, the course of the spin axis of the quasar.
“The alignments in the new data, on scales even bigger than current predictions from simulations, may be a hint that there is a missing ingredient in our current models of the cosmos,” concludes Dominique Sluse.