Black holes have voracious appetites. As these objects, which are so dense that not even light can escape their gravitational pull, chow down on gas and stellar debris, they emit powerful bursts of X-rays, creating what is known as a cosmic X-ray background — a “song” of X-rays being emitted by millions of black holes, which fills the entire sky.
Although astrophysicists have long known about this “cosmic choir,” identification of individual singers has proven elusive.
Now, data gathered by NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) — a space-based X-ray telescope — is finally helping scientists pinpoint the black holes emitting high-energy X-rays, thereby taking a significant step toward resolving the cosmic X-ray background.
“Before NuSTAR, the X-ray background in high energies was just one blur with no resolved sources,” lead author Fiona Harrison, the principal investigator of NuSTAR at Caltech in Pasadena, said in a statement. “We’ve gone from resolving just two percent of the high-energy X-ray background to 35 percent. … We can see the most obscured black holes, hidden in thick gas and dust.”
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SOURCE: International Business Times, Avaneesh Pandey