The European Space Telescope ESA Euclid Discovers 31 New Quasars in the Primordial Universe

Recently, we reported on a new image of the center of the Milky Way captured by the European Space Telescope ESA Euclid. Thanks to data from the new scientific instrument within the Euclid Wide Survey (EWS), a new discovery has been made that does not pertain to our galaxy but to very distant (and ancient) galaxies and the quasars located at their centers. Here’s what we know.

In the study titled Euclid: Discovery of 31 new quasars at 6.6 < z < 7.8, 31 new quasars, among the oldest ever discovered, are examined. In particular, among these new objects, two gigantic galactic nuclei housing supermassive black holes emerge. The most interesting part is that the emission detected from these quasars dates back to when the Universe was only 662 million years old, or just 5% of its current age. Studying these objects is fundamental to understanding the primordial Universe and its evolution.

Daming Yang (University of Leiden) stated, "These early quasars date back to the infancy of the Universe. By finding and studying them, we can better understand how these immense systems formed and grew so quickly – one of the greatest mysteries in astrophysics."

A quasar at the center of a galaxy is a structure associated with a supermassive black hole that is actively attracting large amounts of matter while simultaneously releasing a lot of energy. Because of this intense activity, the galactic core emits more light than the thousands of stars that comprise the galaxy itself, almost "dimming" them.

Researchers emphasize that, despite being so bright, searching for quasars emitting light in the primordial Universe is a daunting challenge due to their rarity and the scarcity of galaxies that had evolved to such an extent. Furthermore, the emission, weak at such distances, can be confused with that of closer stars.

Thanks to the European Space Telescope ESA Euclid, researchers were able to observe the emission not only of particularly bright quasars but also of those that are less luminous, thus obtaining a greater amount of data for a clearer idea of the Universe at that particular moment. According to the study's information, the two oldest quasars are called EUCL J172902.75+641018.1 and EUCL J125308.55+705432.3, with redshifts of 7.77 and 7.69, respectively, making them the oldest quasars ever found (currently) at about 13 billion light-years away. The first of these two quasars has surpassed the previous record with a higher redshift by about 0.13, corresponding to (approximately 15 million years closer to the Big Bang).

In-depth analyses of one of the two oldest quasars suggest that this object could be within a galaxy containing a large amount of dust and gas with a high star formation rate (possibly due to the presence of a supermassive black hole). In general, the new data showcase 12 quasars with redshifts ≥ 7, effectively doubling the number of known quasars at these extreme distances (from only 9 total since 2011). There are quasars classified as "weak", opening a new avenue for the analysis of these even more elusive objects, although no less important. Finally, two quasars (EUCL J1253 and EUCL J1012, with redshifts of 7.69 and 7.61) are the weakest of their kind with redshifts above 7.5.