Using the NASA/ESA Hubble Space Telescope and other space and ground-based observatories, astronomers have discovered SDSS J0749+2255, a closely bound pair of quasars (actively feeding supermassive black holes) hosted by a galaxy merger that existed when the Universe was just 3 billion years old.
Quasars are bright objects powered by voracious, supermassive black holes blasting out ferocious fountains of energy as they engorge themselves on gas, dust, and anything else within their gravitational grasp.
“We don’t see a lot of double quasars at this early time in the Universe. And that’s why this discovery is so exciting,” said Yu-Ching Chen, a graduate student at the University of Illinois at Urbana-Champaign.
Previous observations have identified similar systems in the early stages of merging, when the two galaxies could still be considered clearly separate entities.
But the new results show a pair of quasars blazing away in such close proximity, a mere 10,000 light-years apart, that their original host galaxies are likely well on their way to becoming a single giant elliptical galaxy.
Searching for pairs of supermassive black holes so close to each other during this early epoch is like trying to find the proverbial needle in a haystack.
The challenge is that most black-hole pairs are too close to distinguish individually.
To definitively detect such a system, the two supermassive black holes need to be actively accreting and shining as quasars simultaneously, conditions that are extremely rare.
Statistically, for every 100 supermassive black holes only one should be actively accreting at a given time.
Astronomers know, however, that the distant Universe should be brimming with pairs of supermassive black holes embedded within merging galaxies.
The first hints of such a system were found in Hubble data, which revealed two closely aligned pinpoints of light in the distant Universe.
“Hubble’s sensitivity and resolution provided pictures that allow…
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