Chorus of Black Holes Radiates X-Ray

Black holes may be empty but they do sing.

There's something about supermassive black holes that continue to amaze scientists. They possess some capabilities that bewilder experts because black holes don't really have any light, but from pulling materials from their surroundings black holes are able to emit bursts of X-rays.

The fascinating emission of X-rays from supermassive black holes are considered a "cosmic choir" using X-rays. Astronomers refer to it as the cosmic X-ray background. The identification of singing black holes are being done by NASA's Chandra mission but despite the technology, the loudest black holes that emit the highest-pitched "voices" remain unidentified. But the latest data collected by NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) started identifying the biggest contributor to the cosmic choir.

"We've gone from resolving just 2 percent of the high-energy X-ray background to 35 percent," Fiona Harrison one of the lead investigators of NuSTAR and one of the authors of the study said in a statement. "We can see the most obscured black holes, hidden in thick gas and dust," Harrison added.

This study is vital in understanding the growth and evolution of supermassive black holes and their relationship to their host galaxies. In growth, their gravity also grow more intense that can pull matter towards their center, when the center heats up it boosts the particles creating a glow or the X-ray effect. Based on studies, supermassive black holes with more fuel and gas contents are more likely to emit high-energy X-rays.

The brighter the black hole, the healthier it is from materials it needs to emit the X-ray glow. Now experts can identify different sources of X-ray glow. "Before NuSTAR, the X-ray background in high-energies was just one blur with no resolved sources," Harrison said in a statement. "To untangle what's going on, you have to pinpoint and count up the individual sources of the X-rays," Harrison added.

Today, the NuSTAR is helping astronomers study the "cosmic choir", their voices and X-rays and how they evolve over time.