Astronomers Have Discovered Two Distant and Very Bright 'High Redshift' Quasars

Monday, 21 May 2018 - 7:45PM
Space
Astronomy
Monday, 21 May 2018 - 7:45PM
Astronomers Have Discovered Two Distant and Very Bright 'High Redshift' Quasars
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ESO/M. Kornmesser
Quasars are among the brightest and farthest objects we've found throughout the known universe, but we haven't found very many. So it's always cool when we come across some new ones.

And a team of astronomers have just picked up traces of two new quasars, measuring at a redshift of nearly 5.0, making them the brightest known objects to date with a redshift that high. For context, a redshift is used to measure cosmic objects moving away from us (since the universe is expanding, nearly everything in space has a redshift as they move farther away from us). Anything with a high redshift is farther away from us.

Quasars with redshifts over 4.5 are extremely rare, partly because the light takes such a long time to reach us. Since we're finding light from stars over 13 billion lightyears away, the most distant objects in space can tell us a lot about the early universe, since the universe itself is only 13.7 billion years old.



For a long time, the specific definition of a quasar was a contentious one, but they're now known to be compact and luminous regions which surround supermassive black holes in the centers of galaxies. Compact as they may be, they're still extremely powerful - much like the black holes related to them, although while black holes absorb all visible light, quasars release tons of bright energy which we can pick up. 

The research has been published on arXiv, and is the result of a long campaign of using extremely powerful telescopes, including the Australian National University's 2.3m telescope, the Pan-STARRS1 telescope in Hawaii, and NASA's Wide-field Infrared Survey Explorer (WISE) space telescope.

The two quasars have official and very long names of SMSS J013539.27-212628.4 and SMSS J093032.58-221207.7, with respective 4.94 and 4.86 redshifts.

Now that we know about them, we can study them more. Again, these things are far, and there's a lot to learn about the early universe by examining them.
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