Hubble discovers unexpected double quasar in early universe

A pair of quasars from the early universe have been found by the Hubble Space Telescope. Because of the friction in the tortured material within accretion discs around constantly feeding supermassive black holes at galaxies’ cores, quasars can outshine all other stars in the galaxies, which is why they are also known as bright black holes. The two quasars are merging, and the interaction is driving rapid star formation in both galaxies. Astronomers have only discovered double quasars in the last two decades, but finding a pair at such great distances is perplexing because scientists are unsure how these supermassive black holes could have formed so quickly after the Big Bang.

This is the first time that a pair of quasars have been found in the cosmic noon, a period of time three billion years after the Big Bang when the galaxies in the universe were forming stars at a furious rate. Quasars at that distance are challenging to identify. The two host galaxies are very likely to be in the advanced stages of merging into a single one, as the quasars are at a distance of only 10,000 lightyears from each other. The observations by Hubble were confirmed by ESA’s Gaia Observatory, the Gemini North Telescope, the Keck Observatory, the Jansky Very Large Array and the Chandra X-ray Observatory.

A paper describing the findings has been published in Nature. Co-author of the paper, Yue Shen says, “The confirmation process wasn’t easy and we needed an array of telescopes covering the spectrum from X-rays to the radio to finally confirm that this system is indeed a pair of quasars, instead of, say, two images of a gravitationally lensed quasar.” Another co-author, Xin Liu says, “We’re starting to unveil this tip of the iceberg of the early binary quasar population. This is the uniqueness of this study. It is actually telling us that this population exists, and now we have a method to identify double quasars that are separated by less than the size of a single galaxy.”