Astronomers have discovered a distant cluster of galaxies without the expected supermassive black hole at its center, even though its mass is expected to be between three and 100 billion times that of the Sun.
According to a NASA statement, the black hole was theorized to be in the galaxy cluster Abell 2261, about 2.7 billion light years from Earth, according to observations made between 1999 and 2004.
More recently, West Virginia University astronomers used NASA’s Chandra X-ray Observatory and the Hubble Space Telescope to explore the area, and they couldn’t find the black hole.
A supermassive black hole is present in almost every large galaxy in the known universe. The more massive the galaxy, the bigger the black hole. In fact, this particular black hole was predicted to be one of the largest in history.
To put the idea of something a hundred billion times the mass of the Sun into perspective, the Milky Way’s central supermassive black hole is estimated to be only four million times the mass of the Sun.
Explanations by scientists about the missing black hole
But it is missing and in order to explain this, scientists have given several explanations.
First, the black hole could have been ejected from its host galaxy as two galaxies could have merged into an even more massive galaxy, also known as a “recoiling black hole.”
Second, the respective black holes of the two galaxies could have merged into an even larger supermassive black hole and formed a gigantic core at the center of the resulting mega-galaxy.
Although this phenomenon is yet to be directly observed involving black holes at such a scale, astronomers have observed mergers in much smaller black holes.
In an upcoming paper in the journal American Astronomical Society, a team led by Sarah Burke-Spolaor at West Virginia University presented two other possible explanations: Either there is simply no black hole, or there is a black hole that just isn’t active enough to produce noticeable amounts of X-rays to appear in Chandra observations.
Scientists hope to get a closer look with NASA’s upcoming James Webb Space Telescope.