The largest map of quasars in the Universe published

Madrid. Using data obtained by ESA’s Gaia space mission, astronomers have published the map of quasars with the largest volume of the universe mapped.

These are gas-devouring black holes that, curiously, represent some of the brightest objects in the universe.

The new map charts the location of about 1.3 million quasars in space and time, the most distant of which was shining when the universe – estimated to be 13.7 billion years old – was just 1.5 billion years old. .

“This catalog of quasars differs from all previous catalogs in that it provides us with a three-dimensional map of the largest volume ever created by the universe,” says map co-creator David Hogg, principal research scientist at the Institute’s Center for Astrophysical Computing, in a statement. Flatiron in New York City and professor of physics and data science at New York University.

“It is not the catalog with the most quasars, nor is it the catalog with the best quality quasar measurements, but it is the catalog with the largest total volume of the mapped universe.”

Hogg and his colleagues present the map in a paper published March 18 in The Astrophysical Journal. The main author of the article, Kate Storey-Fisher, is a postdoctoral researcher at the International Physics Center of Donostia.

Scientists built the new map using data from the European Space Agency’s Gaia space telescope. While Gaia’s primary goal is to map the stars of our galaxy, it also inadvertently detects objects outside the Milky Way, such as quasars and other galaxies, while scanning the sky.

“We were able to make measurements of how matter clumps together in the early universe that are as precise as some of the major international survey projects, which is quite remarkable given that we got our data as a ‘bonus’ from the Gaia-focused project. in the Milky Way,” says Storey-Fisher.

Quasars are powered by supermassive black holes at the centers of galaxies and can be hundreds of times brighter than an entire galaxy. As the black hole’s gravitational pull spins nearby gas, the process generates an extremely bright disk and sometimes jets of light that telescopes can observe.

Galaxies inhabited by quasars are surrounded by huge halos of invisible material called dark matter. By studying quasars, astronomers can learn more about dark matter, such as how much it accumulates.

Astronomers can also use the locations of distant quasars and their host galaxies to better understand how the cosmos expanded over time.

For example, scientists have already compared the new quasar map to the oldest light in our cosmos, the cosmic microwave background. As this light travels toward us, it is bent by the network of dark matter that intervenes, the same network drawn by quasars. By comparing them, scientists can measure how strongly matter accumulates.

“It’s been very exciting to see how this catalog stimulates so much new science,” says Storey-Fisher. “Researchers around the world are using the quasar map to measure everything from the initial density fluctuations that seeded the cosmic web to the distribution of cosmic voids and the motion of our solar system through the universe.”

The team used data from Gaia’s third data release, which contained 6.6 million quasar candidates, and data from NASA’s Wide-Field Infrared Survey Explorer and the Sloan Digital Sky Survey. By combining the data sets, the team removed contaminants such as stars and galaxies from the original Gaia data set and more precisely identified the distances to the quasars.

The team also created a map showing where dust, stars, and other disturbances are expected to block our view of certain quasars, which is critical to interpreting the quasar map.

“This catalog of quasars is a great example of how productive astronomical projects are,” says Hogg. “Gaia was designed to measure stars in our own galaxy, but it also found millions of quasars at the same time, giving us a map of the entire universe.”