Astronomers said on April 6, 2021 that they saw two rare double quasars. It is believed that each pair lives in the middle of two galaxies that merge into the very distant universe. Astronomers estimate that only one in 1,000 quasars is double, so finding two double quasars could be seen as 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 another, in a methodical revelation of the mystery whose bright, seemingly unique quasar could actually be double. 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 has 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 analyzed the 3D maps in the Sloan Digital Sky Survey to find double quasar candidates. They then used data from the Gaia Observatory to identify the locations. Gaia is able to detect slight movements in the movement of distant quasars. Because the lights vary depending on the amount of material the black hole consumes at that time, they produce a slightly flickering appearance. The scientists compared the alternating brightness between the quasar pair, as seen in the video above, with that of the double lights flashing at 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 and flickering light of a pair of quasars. Astronomers have 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 partner. It is very close on a cosmic scale of distance; by 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 prodigious amounts of energy. Quasars have such an amazing glow that they can be seen over vast expanses of the universe. Thus, we see them at a time when the universe was young and so they can help reveal the conditions in the early cosmos. Quasars are believed to be in the hearts of young galaxies in the early universe. It is believed that the energy of a quasar is created when a supermassive black hole feeds angrily on collapsing matter. The light of 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 now, we could discover that each pair of quasars merged to form a new giant black hole.
More than 100 double quasars are already known, but none live as far away in space and as far back in time as these new pairs. Scientists hope the findings will produce a new way to test 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 truly the first sample of dual quasars in the peak epoch of galaxy formation that we can use to test ideas about how supermassive black holes eventually come together to form a binary.
As these distant galaxies begin to merge and the gas from gravitational distortions sends the material inward, the quasars ignite. The radiation coming from the quasar will eventually power the winds that sweep the inner region of the galaxy without 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 have a profound impact on the formation of the galaxy in the universe. Finding dual quasars at this early age is important because we can now test our long-standing ideas about how black holes and their host galaxies evolve together.
Larger view. | On the left is the quasar pair J0749 + 2255, which was represented 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, 2019. The galaxies in which they resided they are too weak to be seen with any current telescope. Image via NASA / ESA.
The concept of this artist presents 2 bright quasars and the merging galaxies in which they are located. Both quasars have supermassive black holes in the core. A new study suggests that as the two galaxies join and the quasars approach, the two black holes will join to form an even more massive black hole. Image by NASA / ESA / J. Olmsted / STSci.
One day, a double quasar and a galactic fusion, like the one scientists have seen far away in the universe, will happen much closer to home. Our Milky Way and the neighboring galaxy Andromeda are on a collision course. A few billion years from now, as our two galaxies begin to interact and extract materials from each other, the supermassive black holes, now quiet, in the center of the galaxies will ignite. The collapsing material will ignite the quasars, creating two bright spotlights that will shine as bright or brighter than a full moon in our night sky. Quasar radiation will sterilize the planets and wipe out any civilization at hand.
Conclusion: Scientists have recently released Hubble images of the most distant and oldest pairs of quasars in the merging galaxies.
Source: A hidden population of high-speed double red quasars revealed by astrometry
Through Hubblesite
