Surprising discovery of a double quasar - merging galaxies ignite colliding black holes. Recently, astronomers used the Hubble Space Telescope and other observatories to identify a pair of gravitationally bound quasars embedded inside two merging galaxies that existed when the universe was just 3 billion years old.
This discovery is exciting because it provides clues about the progenitor population of black holes and the emergence of supermassive black holes in the early universe.
Quasars are some of the brightest objects in the universe and are powered by supermassive black holes that are actively feeding on gas and dust. They emit intense energy that can outshine billions of stars. Quasars are vital because they provide information about the early universe when galaxies frequently collided and black holes were engorged with material from close encounters.
Finding close binary quasars is a relatively new area of research that has just developed in the past 10 to 15 years. Today's powerful new observatories have allowed astronomers to identify instances where two quasars are active simultaneously and are close enough to eventually merge.
Over the billions of years that have passed since this pair of quasars existed, they have likely merged into a single, even more, massive black hole. Studying such merging black holes can help astronomers understand the evolution of galaxies and how supermassive black holes are formed.
We’re starting to unveil this tip of the iceberg of the early binary quasar population. This is the uniqueness of this study. It is actually telling us that this population exists, and now we have a method to identify double quasars that are separated by less than the size of a single galaxy.- Xin Liu of the University of Illinois at Urbana-Champaign
The discovery of this pair of quasars is not only exciting because of its rarity, but also because it was found using a new method that could lead to the discovery of more such binary quasars.
By using the Gaia space observatory to search for subtle changes in the position of nearby stars, astronomers can identify quasars that appear to be a single object but are actually a binary pair. This new method will help astronomers better understand the prevalence of binary quasars and the role they play in the formation and evolution of galaxies.
The discovery was made possible by the combined power of several observatories, including NASA's Hubble Space Telescope, the W.M. Keck Observatories, the International Gemini Observatory, NSF's Karl G. Jansky Very Large Array, and NASA's Chandra X-ray Observatory. Each observatory contributed unique data and observations that helped confirm the existence of the binary quasars.
As we continue to explore the universe, discoveries like this one remind us of the incredible complexity and diversity of the cosmos. By studying rare and unique phenomena like binary quasars, astronomers can gain new insights into the formation and evolution of galaxies, black holes, and the universe itself.