An international team of astronomers has discovered the furthest radio galaxy yet, breaking the record for most distant radio galaxy ever discovered, which had been set nearly 20 years before. Its light – incredibly – is coming to us from over 12.7 billion years ago. This object was already in place when the universe was just 7 percent of its current age.
As reported in the Monthly Notices of the Royal Astronomical Society, the discovery marks a new understanding of these objects. Radio galaxies are a particular class of active galaxies that have a supermassive black hole at their center emitting impressive jets of material. The movement of particles emits radio waves, and some of these objects can be a thousand time brighter than our own galaxy in radio waves alone.
The energy to power such an incredible structure comes from the accretion of material by the supermassive black hole. The behemoths at the center of these galaxies accumulate gas and dust in a feeding frenzy, then shoot the material out in jet streams. This material is made up of charged particles and as they accelerate into intergalactic space at almost the speed of light they emit synchrotron radiation, which we detect in radio waves.
Such a setup is not common in the universe. Radio galaxies are in fact very rare, so the discovery of this far-away object puzzled the researchers. Finding a radio galaxy from the first billion years of the universe suggests that mass assembly took place on a very rapid scale.
"It is very surprising how these galaxies have built up their mass in such a short period of time," lead author Aayush Saxena from the Leiden Observatory said in a statement.
"Bright radio galaxies harbor supermassive black holes. It is amazing to find such objects as early in the history of the universe; the time for these supermassive black holes to form and grow must have been very short," co-author Huub Röttgering, also at the Leiden Observatory, added.
The galaxy was first discovered by the Giant Meter-wave Radio Telescope in India, and then verified using the Gemini North telescope in Hawaii and the Large Binocular Telescope in Arizona, to confirm the distance of the object. The previous record holder, discovered in 1999 was about 150 million years older than this object.
The next generation telescopes, both in optical and infrared, as well as radio will continue to probe the mysterious infancy of the universe and perhaps find even older radio galaxies.
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