Astronomers announced the discovery at the American Astronomical Society meeting in Charleston.
Black holes can come in many sizes.
They can be monsters, thousands of times the size of our Sun, sitting at the centre of galaxies devouring stars and gas clouds. Around the black hole can be a swirling mass of superhot gas giving off high-energy radiation. As the black hole's irresistible gravity draws gas into it, cataclysmic amounts of energy are given off. It then enters the black hole and disappears from our universe altogether. Jets of matter often spurt away from the polar regions above the black hole.