Many black holes have been observed sending out bursts of X-rays as matter is drawn in. The chorus of energetic black holes which “sing” with radiation creates what is known as the cosmic X-ray background. Scientists, up until now, have had difficulty locating the sources of the most high-energy X-rays among the cosmic “voices.”
According to EurekAlert, NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) has found, for the first time, large numbers of black holes emitting high-energy X-rays. NuSTAR is the first telescope able to translate high-energy X-rays into clear pictures.
“Before NuSTAR, the X-ray background in high-energies was just one blur with no resolved sources,” Fiona Harrison of Caltech said. “To untangle what’s going on, you have to pinpoint and count up the individual sources of the X-rays.”
“We’ve gone from resolving just 2 percent of the high-energy X-ray background to 35 percent,” Harrison said. “We can see the most obscured black holes, hidden in thick gas and dust.”
Since black holes cannot be observed directly using visible light, observations of high-energy X-rays can help scientists analyze the objects and activities present in the areas surrounding supermassive black holes.
Further study of the high-energy outputs detected by NuSTAR can help scientists better understand how supermassive black holes develop over time. Understanding of the evolution of black holes can help astronomers learn how the galaxies surrounding supermassive black holes form and develop.
“We knew this cosmic choir had a strong high-pitched component, but we still don’t know if it comes from a lot of smaller, quiet singers, or a few with loud voices,” Daniel Stern of NASA said. “Now, thanks to NuSTAR, we’re gaining a better understanding of the black holes and starting to address these questions.”
The study will be published in The Astrophysical Journal.