The European Space Agency’s (ESA) Euclid space telescope has spotted 31 previously unknown quasars dating to the universe’s earliest chapter, including the two oldest ever found.
The discoveries, described July 6 in the journal Astronomy & Astrophysics, more than double the number of known quasars from that primordial era and could help astronomers unravel one of cosmology’s biggest mysteries: how supermassive black holes grew so enormous so quickly after the Big Bang.
“It’s a big step towards understanding these fascinating objects on a more fundamental level,” Antonio La Marca, an ESA research fellow on the Euclid team, said in a statement.
Quasars are among the brightest objects in the universe. They form when gas and dust spiral into a galaxy’s central supermassive black hole, heating up and releasing enormous amounts of energy that can outshine the galaxy itself. Each of the two most ancient quasars detected in the new study shone with the light of a trillion suns, according to the researchers.
Euclid spotted the quasars while surveying the distant universe. Twelve of them have redshifts of 7 or higher, meaning their light has traveled for more than 13 billion years and dates to the universe’s first 770 million years. Two of the objects, with redshifts of 7.77 and 7.69, are the most ancient quasars ever identified, shining just 670 million years after the Big Bang, when the universe was only about 5% of its current age.
“These early quasars date back to the Universe’s infancy,” Daming Yang, an astronomer at Leiden University in the Netherlands and first author of the new study, said in the statement. “By finding and studying them, we can better understand how these enormous systems formed and grew so quickly — one of the greatest mysteries in astrophysics.”
Finding quasars from the early universe has long been difficult because they are rare and incredibly distant. Until now, astronomers had identified only the brightest examples, making it difficult to understand the broader population during this early era. Euclid’s wide-field survey is changing that by detecting fainter quasars across huge swaths of the sky.
The latest discoveries represent only a fraction of what the telescope is expected to find during its six-year mission, which will cover more than one-third of the total sky once complete. Mounted with a pair of instruments that see in visible and near-infrared light, Euclid is currently assembling the largest-ever 3D map of the universe. Scientists expect the survey to uncover hundreds of similarly ancient quasars, providing an unprecedented look at how the universe’s earliest galaxies and supermassive black holes evolved.
Euclid has also taken some time to study the nearby universe, revealing more than 60 million individual stars packed into the Milky Way’s center in a sparkling image released in late June.
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