The largest map of active supermassive black holes in the universe is released
Astronomers have mapped the universe’s largest volume with a new map of active supermassive black holes that live at the centers of galaxies. These black holes, called quasars, are ironically some of the brightest objects in the universe.
The name Quasar, quasar In English it is the abbreviation for “quasi-stellar radio source”. They appear in the black hole at the center of galaxies and are an astronomical source of electromagnetic energy that includes radio frequencies and visible light.
The new map shows the location of about 1.3 million quasars in space and time, of which the most distant quasar shone when the universe was just 1.5 billion years old (for comparison, the universe is now 13.7 billions of years old).
INFOGRAPHY EXPLAINING THE CREATION OF A NEW MAP OF AROUND 1.3 MILLION QUASARS OF THE ENTIRE VISIBLE UNIVERSE. IMAGE: ESA/GAIA/DPAC; LUCY READING-IKKANDA/SIMONS FOUNDATION; K. STOREY-FISHER ET AL. 2024
“This catalog of quasars differs from all previous ones in that it gives us a three-dimensional map of the largest volume of the universe to date,” says David Hogg, co-creator of the map and a researcher at the Center for Computational Astrophysics at the Flatiron Institute in New York and professor of Physics and Data Science at New York University. “It’s not the catalog with the most quasars and it’s not the catalog with the highest quality measurements of quasars, but It is the catalog with the largest total volume in the mapped universe«.
Hogg and his colleagues present the map in a paper published in the Astrophysical Journal. The article’s lead author, Kate Storey-Fisher, is a postdoctoral researcher at Donostia International Physics Center (Spain).
Scientists created the new map using data from the European Space Agency’s Gaia space telescope. Although Gaia’s main goal is to map the stars in our galaxy, it also inadvertently discovers objects outside the Milky Way, such as quasars and other galaxies, as it scans the sky.
We were able to measure the agglomeration of matter in the early universe as precisely as some of the large international research projects, which is quite amazing considering we received our data as an “extra” to the project. Gaia, with the Milky Way at the center,” says Storey-Fisher.
Why are black holes so bright?
Quasars are powered by supermassive black holes located at the centers of galaxies and can be hundreds of times brighter than an entire galaxy. When the black hole’s gravitational pull rotates nearby gas, the process creates an extremely bright disk and sometimes beams of light that can be observed with telescopes.
The galaxies where quasars live are surrounded by huge halos of invisible material called dark matter. Studying quasars allows astronomers to better understand dark matter, such as how strongly it clumps together.
Astronomers can also use the locations of distant quasars and their host galaxies to better understand how the cosmos has expanded over time. For example, scientists have already compared the new quasar map with the oldest light in our cosmos, the cosmic microwave background. As this light travels toward us, it is bent by the dark matter network involved, the same network created by quasars. By comparing the two, scientists can measure the intensity at which matter clumps together.
“It was very exciting to see how this catalog stimulated so many scientific advances,” says Storey-Fisher. “Researchers around the world use the quasar map to measure everything from the initial density fluctuations that formed the cosmic web to the distribution of cosmic voids and the movement of our solar system through the universe.”
The team used data from Gaia’s third paper, which contained 6.6 million possible quasars, as well as 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 determined the distances to the quasars more precisely. The team also created a map showing where dust, stars and other disturbances are likely to block our view of certain quasars, which is crucial for 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 the stars in our own galaxy, but at the same time it also found millions of quasars, giving us a map of the entire universe.”
REFERENCE
Quaia, the Gaia unWISE quasar catalog: A full-sky spectroscopic quasar sample
Source: Simons Foundation
