Astronomers have caught radio signals of a supermassive black hole devouring a star. Radio observations revealed the presence of a jet of high-energy particles.
The radio signature closely matched the pattern of X-ray emissions, suggesting a close relationship between the two phenomena.
“This is telling us the black hole feeding rate is controlling the strength of the jet it produces,” Dheeraj Pasham, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research, said in a news release. “A well-fed black hole produces a strong jet, while a malnourished black hole produces a weak jet or no jet at all. This is the first time we’ve seen a jet, that’s controlled by a feeding supermassive black hole.”
Basically, what’s happening here, astronomers call it a tidal disruption event. When a star passes close to a black hole, the black hole’s gravitational pull generates tidal forces on the star, similar to the way in which the moon stirs up tides on Earth.
A black hole’s gravitational forces trigger a tidal disruption event inside a star that wanders too close. Thus, the black hole flattens the stellar material, apart and pulls it into the accretion disk. This entire process generates colossal bursts of energy across the electromagnetic spectrum.
Observing the Phenomenon
Astronomers have observed the phenomenon in optical, ultraviolet and X-ray bands, but less frequently in radio emissions.
Scientists think X-ray emissions produced by a black hole consuming a star originate from the inner portion of the black hole’s accretion disk. Meanwhile, ultraviolet emissions, are produced in the outer rings of the disk.
However, astronomers find it hard to determine where radio emissions originate from.
“We know that the radio waves are coming from really energetic electrons that are moving in a magnetic field — that is a well-established process,” Pasham said. “The debate has been, where are these really energetic electrons coming from?”
Scientists have published their findings in the Astrophysical Journal.