Daily Double: Hubble notices a pair of quasars in merging galaxies

Peering back 10 billion years into the universe’s past, NASA’s Hubble Space Telescope has discovered a pair of quasars that are so close to each other. Due to their proximity, they appear as a single object.

According to scientists, the reason for this proximity is that they reside in the core of two merging galaxies.

The group continued to conquer the “daily double” by finding another pair of quasars in the second binary of the galaxy in the collision. The discovery of these four quasars offers a new way of examining collisions between galaxies and merging supermassive black holes in early space.

Lead researcher Yue Shen of the University of Illinois at Urbana-Champaign said, We estimate that in outer space there is one double quasar for every 1,000 quasars. So finding these double quasars is like finding a needle in a haystack.

Research team member Nadia Zakamska of Johns Hopkins University in Baltimore, Maryland, said, This is really the first sample of dual quasars at the peak of the galaxy formation era. We can use it to examine ideas about how supermassive black holes merge to eventually create a binary system.

Quasars have a profound effect on the formation of galaxies in space. Finding dual quasars in this early era is necessary because we can now test our long-held ideas about how black holes and their host galaxies evolve together.

Quasars do not travel through space in any measurable way. However, their flickering could be evidence of random light fluctuations because each individual from a pair of quasars differs in brightness. Quasars glow brightly at intervals of days to months, depending on the feeding schedule of their black ole. This alternating brightness between pairs of quasars is similar to watching a signal to cross a railroad from a distance. While the lights on both sides of the stationary signal alternately flash, the sign gives the illusion of “jiggling”.

Journal reference:
  1. Shen, Y., Chen, YC., Hwang, HC. and others. Hidden population of double quasars with high redshift detected by astrometry. Nat Astron (2021). DOI: 10.1038 / s41550-021-01323-1

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