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1.3 million supermassive black holes cataloged in largest-ever map

In an unparalleled feat of cosmic cartography, astronomers have unveiled the most expansive map yet of the universe’s active supermassive black holes, known as quasars.

Moreover, this new map catalogs a mind-boggling 1.3 million quasars across the visible universe. Consequently, it represents a significant advance in our quest to unravel the mysteries of dark matter and the fabric of the cosmos.

Quasars – supermassive black holes at galaxy centers – are ironically the brightest cosmic objects, illuminating space’s darkest corners.

Further, the new map tracks quasars across space and time. It notably features those from when the universe was merely 1.5 billion years old, offering a stark contrast to its current age of 13.7 billion years.

A map like no other

David Hogg, a senior research scientist at the Flatiron Institute’s Center for Computational Astrophysics in New York City and a professor of physics and data science at New York University, emphasizes the uniqueness of this quasar catalog.

“This catalog offers us a three-dimensional map of the universe’s largest-ever volume,” Hogg explains. Unlike other catalogs, this one may not have the highest number of quasars or the finest quality measurements. However, it excels in covering an unprecedented expanse of the universe.

The map, unveiled in The Astrophysical Journal, is the creation of Hogg’s team, featuring lead author Kate Storey-Fisher, a postdoctoral researcher at Spain’s Donostia International Physics Center. It’s based on data from the European Space Agency’s Gaia telescope, which, while mainly mapping the Milky Way, also detects quasars and galaxies beyond.

Storey-Fisher noted the significance of their work. “We’ve achieved measurements of early universe matter clustering that rival those from major international survey projects — a remarkable feat considering our data came as a ‘bonus’ from the Gaia project, primarily focused on the Milky Way,” she said.

Quasars and the mystery of dark matter

Quasars illuminate dark matter’s mysteries and the universe’s expansion, revealing how dark matter clusters around them.

Consequently, this map has sparked diverse scientific investigations. Researchers are exploring topics ranging from the cosmic web’s formation to the distribution of cosmic voids. Additionally, they are examining our solar system’s movement through space.

From Gaia to the cosmos

The team’s work was enhanced by Gaia’s third data release, featuring 6.6 million quasar candidates, and data from NASA’s Wide-Field Infrared Survey Explorer and the Sloan Digital Sky Survey.

This approach helped filter non-quasar objects and accurately measure quasar distances. They also created a map to identify areas where dust, stars, and other obstacles could block views of quasars, crucial for accurate interpretation.

A universal map beyond stars

Hogg reflected on the broader significance of their work. “This quasar catalog exemplifies the fruitful outcomes of astronomical projects. Gaia was tasked with mapping our galaxy’s stars, yet it inadvertently provided us with a universal map through the discovery of millions of quasars,” Hogg explained.

This monumental mapping effort enhances our understanding of the cosmos. It also exemplifies the unexpected discoveries that can emerge from scientific inquiry, paving the way for future explorations of the universe’s mysteries.

More about supermassive black holes

As discussed above, supermassive black holes are among the most fascinating and extreme objects in the universe.

Unimaginable mass

Supermassive black holes, located at the centers of galaxies, can have masses millions to billions of times greater than that of the Sun. For example, the supermassive black hole at the center of the Milky Way, known as Sagittarius A*, has a mass about 4.6 million times that of the Sun.

Invisible giants

Despite their massive size, supermassive black holes themselves are invisible because they trap all light within their event horizon. However, they can be detected through their interactions with surrounding matter, such as the accretion disks of glowing gas that often orbit them, and the powerful jets of particles they can emit.

Foundational role in galaxies

Supermassive black holes are believed to play a critical role in the formation and evolution of galaxies. There is a strong correlation between the mass of a supermassive black hole and various properties of its host galaxy, suggesting a deep, intrinsic link between galaxies and their central black holes.

Quasars and active galactic nuclei

Some supermassive black holes are extraordinarily bright because they actively accrete matter from their surroundings at high rates. These actively feeding black holes can power quasars and other types of active galactic nuclei (AGN), making them some of the most luminous objects in the universe, visible across vast cosmic distances.

Gravitational waves

The merger of supermassive black holes can produce ripples in the fabric of spacetime, known as gravitational waves. Detecting these waves from supermassive black hole mergers requires future space-based observatories, as these events produce low-frequency waves that cannot be detected by current Earth-based facilities.

Einstein’s predictions

The study of supermassive black holes and their effects on spacetime and matter around them has provided strong evidence in support of Albert Einstein’s theory of general relativity. Observations of stars orbiting closely around Sagittarius A* have confirmed predictions of general relativity with high precision.

Mysterious formation of supermassive black holes

The formation of supermassive black holes remains an area of active research. One theory suggests they could form from the collapse of extremely massive clouds of gas in the early universe, while another proposes they grow from smaller black holes that merge and accumulate mass over time.

Event Horizon Telescope achievements

In 2019, the EHT collaboration released the first-ever “image” of a supermassive black hole, located in the galaxy M87. This historic achievement was actually a picture of the black hole’s shadow against its surrounding accretion disk, providing direct visual evidence of a black hole’s existence.

These facts highlight just how much supermassive black holes are at the heart of many of the most significant and intriguing astrophysical phenomena in the universe.

The full study was published in The Astrophysical Journal.


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