NASA | GSFC | STScI | Hubble Site | Univ of Illinois | 2021 Apr 06
NASA's Hubble Space Telescope is "seeing double." Peering back 10 billion years into the universe's past, Hubble astronomers found a pair of quasars that are so close to each other they look like a single object in ground-based telescopic photos, but not in Hubble’s crisp view.This artist's conception shows the brilliant light of two quasars residing in the cores
of two galaxies that are in the chaotic process of merging. The gravitational tug-of-
war between the two galaxies stretches them, forming long tidal tails and igniting a
firestorm of starbirth. Credits: NASA, ESA, and J. Olmsted (STScI)
The researchers believe the quasars are very close to each other because they reside in the cores of two merging galaxies. The team went on to win the "daily double" by finding yet another quasar pair in another colliding galaxy duo. ...
"We estimate that in the distant universe, for every 1,000 quasars, there is one double quasar. So finding these double quasars is like finding a needle in a haystack," said lead researcher Yue Shen ...
The discovery of these four quasars offers a new way to probe collisions among galaxies and the merging of supermassive black holes in the early universe, researchers say.
Quasars are scattered all across the sky and were most abundant 10 billion years ago. There were a lot of galaxy mergers back then feeding the black holes. Therefore, astronomers theorize there should have been many dual quasars during that time. ...
A hidden population of high-redshift double quasars unveiled by astrometry ~ Yue Shen et al
- Nature Astronomy (online 01 Apr 2019) DOI: 10.1038/s41550-021-01323-1