Astronomers said on April 6, 2021 that they had seen two rare double quasars. It is believed that each pair resides in the middle of two galaxies merging into the very distant universe. Astronomers estimate that only one in every 1,000 quasars is double, so finding two double quasars could be considered lucky. Astronomers would tell you, however, that they did not use luck. They used a series of telescopes that led them from one step to the next, in a methodical unraveling of the mystery of what brilliant seemingly simple quasars could really be twice as many. As lead researcher Yue Shen of the University of Illinois at Urbana-Champaign said:
Finding these double quasars is like finding a needle in a haystack.
A collaboration between scientists and some of the best telescopes in the world led to new images of double quasars. The study was published on April 1, 2021 in the peer-reviewed journal Nature Astronomy.
To find the quasar pairs, astronomers examined 3D maps from the Sloan Digital Sky Survey to find dual quasar candidates. They then used data from the Gaia Observatory to determine locations. Gaia is able to detect slight shocks in the movement of distant quasars. Because quasars vary in brightness depending on the amount of material the black hole consumes at that time, they produce a slight flickering appearance. The scientists compared the alternating brightness between the pair of quasars, as seen in the video above, with that of the double flashing lights on a railroad crossing. Finally, the team of scientists used the Hubble Space Telescope to imagine four candidates, two of whom turned out to be close pairs of quasars.
The video simulation above shows the bright, bright light of a pair of quasars. Astronomers deduced that flashing light is a telltale sign of the presence of two quasars and not a single object.
Each of the two newly discovered pairs of quasars (or four quasars in total) were discovered 10,000 light-years from their companion. This is very close to a cosmic distance scale; in comparison, our sun is about 26,000 light-years from the supermassive black hole in the center of our Milky Way galaxy.
A quasar is an object in the distant universe that produces enormous amounts of energy. Quasars have such an amazing brilliance that they can be seen across vast expanses of the universe. Thus, we see them at a time when the universe was young and therefore can help reveal the conditions of the first cosmos. Quasars are believed to be at the heart of young galaxies in the early universe. It is believed that the energy of a quasar is created when a supermassive black hole feeds furiously on falling matter. The light from these two pairs of quasars comes to us from a time when the universe was about 10 billion years old. If we could see them today, as they are right now, we could find that each pair of quasars has merged to form a new giant black hole.
More than 100 double quasars are already known, but none reside as far in space and as far back in time as these new pairs. Scientists hope the findings will give a new way to probe collisions between galaxies and the fusion of supermassive black holes in the early universe. Team member Nadia Zakamska of Johns Hopkins University said:
This is actually the first sample of dual quasars in the peak epoch of galaxy formation that we can use to investigate ideas about how supermassive black holes come together to end up forming a binary.
When these distant galaxies begin to fuse and the gas from gravitational distortions sends material inward, the quasars ignite. The radiation from the quasar will eventually feed the winds that scatter the inner region of the galaxy free of gas and dust. This creates a lack of star-forming material, and as star formation ceases, galaxies settle into their elliptical shapes.
Zamaska explained the importance of this discovery:
Quasars profoundly influence the formation of galaxies in the universe. Finding dual quasars in this early era is important because we can now test our long-held ideas about how black holes and their host galaxies evolve together.
View larger. | On the left is the quasar pair J0749 + 2255, which was captured by the Hubble Space Telescope on January 5, 2020. On the right is the quasar pair J0841 + 4825, which was represented by Hubble on November 30. of 2019. The galaxies in which it resides are too faint to be seen with any current telescope. Image via NASA / ESA.
This artist’s concept shows two bright quasars and the galaxies in which they reside. Both quasars have supermassive black holes in the core. A new study suggests that as the two galaxies merge and the quasars approach, the two black holes will merge to form an even more massive black hole. Image via NASA / ESA / J. Olmsted / STSci.
One day, a double quasar and a galactic fusion like the one scientists have seen all over the universe will pass much closer to home. Our Milky Way galaxy and the neighboring Andromeda galaxy are colliding. Within a few million years, as our two galaxies begin to interact and pull material out of each other, the current silent supermassive black holes in the galaxy centers will ignite. Falling material will illuminate the quasars, creating two bright spotlights that will shine as bright or brighter than a full moon in our night sky. The radiation from the quasars will sterilize the planets and wipe out any civilization within reach.
Summary: Scientists have recently published Hubble images of the most distant and ancient pairs of quasars in merging galaxies.
Source: a hidden population of double quasars of great redshift revealed by astrometry
Via Hubblesite
