Sunday 25 May 2025
A team of astronomers has made a fascinating discovery about quasars, incredibly luminous objects that are thought to be powered by supermassive black holes at the centers of galaxies. By analyzing data from two infrared surveys, the researchers were able to identify nearly 2,500 quasars that show consistent variability over long periods of time.
Quasars are among the brightest objects in the universe, outshining entire galaxies and emitting enormous amounts of energy across a wide range of wavelengths. They’re thought to be powered by supermassive black holes, which are capable of consuming vast amounts of gas and dust as they grow. The variability of quasars is intriguing because it provides clues about how these black holes interact with their surroundings.
The researchers used data from the Two Micron All Sky Survey (2MASS) and the VISTA Hemisphere Survey (VHS), two infrared surveys that captured images of the sky in the 1990s and 2009-2017, respectively. By comparing the brightness of quasars in these datasets, they were able to identify objects that showed significant changes in their luminosity over time.
One of the key findings is that many of these variable quasars are relatively faint, which suggests that they may be farther away than previously thought. This raises interesting questions about how these distant quasars are able to sustain such high levels of activity, given that they’re likely powered by black holes with masses millions or even billions of times that of our sun.
The researchers also found that the variability of quasars decreases as you move towards longer wavelengths, which is consistent with what we’d expect if these objects are indeed powered by supermassive black holes. The team was able to use this information to create a structure function, which is a statistical tool used to analyze the properties of variable sources.
The discovery has important implications for our understanding of quasars and their role in shaping the universe as we know it today. Quasars are thought to have played a key role in reionizing the universe during its early days, and studying their variability can help us better understand how they interact with their surroundings.
This study is just the latest in a long line of research aimed at uncovering the secrets of quasars. By continuing to explore these enigmatic objects, astronomers hope to gain a deeper understanding of the fundamental laws of physics that govern our universe.
Cite this article: “Astronomers Uncover Secrets of Variable Quasars”, The Science Archive, 2025.
Quasars, Supermassive Black Holes, Infrared Surveys, Variability, Luminosity, Galaxies, Universe, Reionization, Structure Function, Astronomy
