Astronomers from the Harvard-Smithsonian Center for Astrophysics have found what they believe is an intermediate sized black hole at the heart of a nebula in a nearby galaxy. Since black holes themselves are invisible, they located it because a spot inside the nebula is emitting a tremendous amount of X-rays, and illuminating a 100 light-year swath. By calculating the amount of X-rays pouring out, astronomers estimate that the black hole has about 25-40 solar masses. It’s unknown how these intermediate-sized black holes form, since so few of them have ever been seen.
A team of European astronomers has used a virtual observatory to find 30 previously undiscovered black holes. The team combined images from several observatories (Hubble, Chandra, ESO) in many wavelengths of light (from infrared to X-ray) into a comprehensive computer catalog of the night sky. They uncovered these new black holes by looking at galaxies which are edge on, so the supermassive black holes at their centre are obscured by a cloud of gas and dust. By comparing between the different wavelengths of light, they were able to spot the new black holes.
Researchers from Penn State University have developed a computer model that describes the interaction of a binary black hole system; where two black holes orbit one another. Previous models have fallen apart because the gravity of the black holes distorts the surrounding space so dramatically, it’s almost impossible to calculate. This unusual situation could generate gravity waves detectable from Earth, which so far have only been theorized by mathematicians.
Astronomers from several US universities have developed a scenario where colliding black holes could be ejected from their galaxy. When two galaxies merge, their central supermassive black holes will orbit one another and eventually collide. When this merge happens, the radiation pressure is so large that it could theoretically knock the black hole out of the centre of the galaxy. Although it should be incredibly rare, it could be possible to spot a black hole in a recently merged galaxy which isn’t at the centre where it normally belongs.
Image credit: ESO A team of astronomers have spotted an otherwise normal star make a close pass with the supermassive black hole that lurks at the centre of our Milky Way Galaxy. At its closest approach, the star was only 17 light-hours away from the black hole (three times the distance of the Sun to […]