Euclid Space Telescope Discovers The Oldest Quasars in the Universe
The Euclid space telescope launched by the European Space Agency (ESA) has made a groundbreaking discovery: a collection of 31 of the oldest quasars ever found. Two of these massive, luminous galactic cores, powered by supermassive black holes, represent the earliest quasars observed in the universe’s history. When the universe was just 670 million years old—only 5% of its current age—these quasars emitted light equivalent to a trillion suns.
Insights into Quasars
Quasars are unique cosmic phenomena that occur during a brief phase in the life of a galaxy. During this phase, large amounts of matter spiral into a central supermassive black hole, releasing enormous amounts of energy. As a result, the core of a quasar shines brighter than any other entity in the universe, often outshining its host galaxy by hundreds to thousands of times.
For decades, astronomers have sought to uncover the universe’s first quasars, as these objects provide insights into the conditions during the earliest days of the cosmos, including how supermassive black holes and galaxies formed. However, discovering these early quasars has been a challenging task due to their rarity and the faintness of their ancient light, which can easily be mistaken for the light of nearby stars.
A New Era of Discovery with Euclid
Launched in 2023, Euclid is venturing deeper into this enigmatic domain of early cosmic history. It has unearthed an unprecedented number of 31 new quasars from this early universe period, reaching back to a time when the cosmos had only 5% of its current age.
Daming Yang from Leiden University in the Netherlands, the lead author of the publication on this discovery, stated, “These early quasars originate from the very beginnings of the universe. By finding and studying them, we can better understand how these massive systems formed and grew so quickly—one of the greatest mysteries of astrophysics.”
Analyzing the Iceberg’s Tip
Previously known early quasars were merely the tip of the iceberg—bright outliers that were easiest to detect. The recent findings by Euclid change the narrative, capturing not only these bright exceptions but also a substantial portion of the older quasar population.
Daming notes, “Euclid is a true milestone. In the past, we could only find a handful of the brightest ancient quasars, but with Euclid, we can efficiently survey vast areas of the sky to capture much fainter light. It is a unique tool for quasar hunting.”
Among the discoveries are 12 new quasars with a redshift—a measure related to the distance and movement of light due to the expanding universe—of 7 or greater, corresponding to the first 770 million years of the universe. The two oldest discovered quasars, EUCL J172902.75+641018.1 and EUCL J125308.55+705432.3, have redshifts of 7.77 and 7.69, respectively, marking a new record for the oldest quasars ever detected.
A Significant Leap Forward
This discovery effectively doubles the number of known quasars of such ancient origins. Notably, it previously took over a decade to identify around ten quasars with a redshift of 7 or more. However, Euclid achieved this in just one year.
Antonio La Marca, an ESA research fellow within the Euclid team, emphasized, “The Euclid team has conducted a genuine ‘inventory’ of quasars from the universe’s infancy for the first time. This is a significant step toward a more fundamental understanding of these fascinating objects.”
A Glimpse into Cosmic History
The oldest quasars discovered are not just intriguing entities; they are like time machines that help us explore the early universe and understand the emergence of the first generation of galaxies. Valeria Pettorino, ESA’s project scientist for Euclid, remarked, “Old quasars are rare discoveries. They are not just interesting in their own right but offer insights into the early universe’s conditions.”
The capabilities of Euclid are unparalleled. With a broad observational area, great depth of focus, high-resolution imaging, and unique space-based infrared sight, this telescope allows scientists to identify rare, extremely distant objects much more efficiently than before.
Conclusion
The 31 quasars presented here were discovered in data from the Euclid Wide Survey, which, upon completion, will cover over one-third of the entire sky. As Euclid delves into the secrets of the dark universe, monitoring its composition, history, and development, it provides invaluable insights into the vast cosmic landscape, revealing countless quasars along the way.
With its combination of technological advancement and collaborative efforts from thousands of scientists and engineers, Euclid is not just a telescope; it is a beacon guiding us through the vast and intricate tapestry of our universe’s history.
