of new mapThis quasar, called Quaia, contains about 1,295,502 quasars from across the visible universe and could help astronomers better understand the properties of dark matter.
story fisher other. This is an all-sky quasar catalog that samples the largest comoving volume of any existing spectroscopic quasar sample.Image credit: Story Fisher other., doi: 10.3847/1538-4357/ad1328.
Quasars are powered by supermassive black holes at the centers of galaxies and can be hundreds of times brighter than entire galaxies.
When the black hole's gravity kicks up nearby gas, the process creates a very bright disk, and sometimes a jet of light, that can be observed with telescopes.
The galaxies that quasars live in are hidden in huge clouds of invisible dark matter.
The distribution of dark matter gives insight into how much dark matter is present in the universe and how strongly clustered it is.
Astronomers compare these measurements across cosmic time to test current models about the composition and evolution of the universe.
Quasars are so bright that astronomers use them to map dark matter in the distant universe and fill in a timeline of how the universe evolved.
For example, scientists are already comparing the new quasar map to the Cosmic Microwave Background, the oldest snapshot of light in the universe.
As this light travels to us, it is bent by an intervening web of dark matter (the same web drawn by quasars), and by comparing the two, scientists can determine how matter changes over time. You can measure how strongly it clumps together.
“The new quasar catalog differs from all previous catalogs in that it provides the largest volumetric three-dimensional map in the history of the universe,” said David, an astronomer at the Center for Computational Astrophysics at the Flatiron Institute in New York.・Professor Hogg said. University.
“This is not the catalog with the most quasars or the highest quality quasar measurements, but it is the catalog with the largest total volume of the universe mapped.”
Professor Hogg and his colleagues constructed the Quasar map using data from the third data release of ESA's Gaia mission, which includes 6.6 million quasar candidates, as well as data from NASA's Wide-field Infrared Explorer and Sloan Digital Sky Survey. did.
By combining the datasets, contaminants such as stars and galaxies were removed from Gaia's original dataset and the distance to the quasar was determined more precisely.
“We were able to measure how matter clustered in the early universe with as much precision as those from major international research projects. Data as a 'bonus' from the Milky Way This is quite remarkable considering that we got . We are focusing on the Gaia project,” said Dr. Kate Storey-Fisher, a postdoctoral researcher at the International Physics Center Donostia.
“It's very exciting to see this catalog spurring so much new science.”
“Researchers around the world use quasar maps to measure everything from variations in the initial density that seeds the cosmic web, to the distribution of voids in the universe, to the movement of our solar system through space. ”
Astronomers have created a map showing where dust, stars, and other nuisances are expected to obstruct the view of certain quasars. This is important in interpreting quasar maps.
“This catalog of quasars is a great example of how productive astronomy projects can be,” Professor Hogg said.
“Gaia was designed to measure stars in our galaxy, but it also discovered millions of quasars, giving us a map of the entire universe.”
of result will appear in astrophysical journal.
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Kate Story Fisher other. 2024. Quair, Gaia-unWISE quasar catalog: all-sky spectroscopic quasar samples. APJ 964, 69; doi: 10.3847/1538-4357/ad1328
Source: www.sci.news
