Largest map ever created of the universe’s active supermassive black holes published

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An infographic explaining the creation of a new map of around 1.3 million quasars across the visible universe. Credit: ESA/Gaia/DPAC; Lucy Reading-Ikkanda/Simons Foundation; K. Storey-Fisher et al. 2024

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An infographic explaining the creation of a new map of around 1.3 million quasars across the visible universe. Credit: ESA/Gaia/DPAC; Lucy Reading-Ikkanda/Simons Foundation; K. Storey-Fisher et al. 2024

Astronomers have mapped the largest volume of the universe ever created with a new map of active supermassive black holes living at the centers of galaxies. Called quasars, gas-guzzling black holes are, ironically, 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 shone when the universe was just 1.5 billion years old. (For comparison, the universe is now 13.7 billion years old.)

“This quasar catalog differs from all previous catalogs in that it gives us a three-dimensional map of the largest volume of the universe,” says the map’s co-creator, David Hogg, a senior research scientist at the Center for Computational Astrophysics at the Flatiron Institute in New York City and a 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 an article published in The Astrophysical Magazine. The paper’s lead author, Kate Storey-Fisher, is a postdoctoral researcher at the Donostia International Physics Center in Spain.

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 in our galaxy, it also inadvertently detects objects outside the Milky Way, such as quasars and others. galaxieswhile scanning the sky.

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

This graphic representation of the map shows the location of the quasars from our point of view, the center of the sphere. Quasar-empty regions are where our galaxy’s disk blocks our view. Quasars with higher redshifts are further away from us. Credit: ESA/Gaia/DPAC; Lucy Reading-Ikkanda/Simons Foundation; K. Storey-Fisher et al. 2024

Quasars work with 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 enormous 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 map of quasars with 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 the third Gaia data release, containing 6.6 million quasar candidatesand 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, they give us a map of the entire universe.”

More information:
Kate Storey-Fisher et al, Quaia, the Gaia-unWISE quasar catalogue: an all-sky spectroscopic quasar sample The Astrophysical Magazine (2024). DOI: 10.3847/1538-4357/ad1328. …847/1538-4357/ad1328

Provided by the Simons Foundation

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