Quasars are galaxies with very active supermassive black holes at their centers. These black holes are surrounded by spinning discs of extremely hot material that is often spewed out in long jets along their axes of rotation.
Dr Damien Hutsemekers of the University of Liege in Belgium used the Very Large Telescope in Chile to observe 93 quasars that were known to form huge groupings spread over billions of light-years.
“The first odd thing we noticed was that some of the quasars’ spin axes were aligned with each other – despite the fact that these quasars are separated by billions of light-years,” explained Dr Hutsemekers, who is the first author of the paper published in the journal Astronomy & Astrophysics (arXiv.org preprint).
“When astronomers look at the distribution of galaxies on scales of billions of light-years they find that the galaxies form a cosmic web of filaments and clumps. This intriguing arrangement of material is known as large-scale structure.”
Dr Hutsemekers and his colleagues found that the spin axes of the quasars were linked not just to each other, but also tend to be parallel to their host large-scale structures.
“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,” said study co-author Dr Dominique Sluse from the University of Liege and the Argelander-Institut für Astronomie in Bonn, Germany.
“Our data provide the first observational confirmation of this effect, on scales much larger that what had been observed to date for normal galaxies.”
The astronomers could not see the rotation axes or the jets of the quasars directly.
Instead they measured the polarization of the light from each quasar and, for 19 of them, found a significantly polarized signal.
The direction of this polarization, combined with other information, could be used to deduce the angle of the accretion disc and hence the direction of the quasar spin axis.
“The alignments in the new data may be a hint that there is a missing ingredient in our current models of the cosmos,” Dr Sluse concluded.
