The Hubble Space Telescope is one of the most powerful in existence, but even with its advanced technology astronomers are sometimes stumped. This was the case when they came across a galaxy that appeared to have two nuclei. The galaxy intrigued them so much that it caused an international team of scientists to be assembled for research on this phenomenon. Read more about what has been uncovered!
The galaxy is called NGC 1097 and it is about 47 million light-years away from Earth. It has a disk that spans 40,000 light-years across and an inner ring that spans 12,000 light-years. The two nuclei vary in brightness as one would expect if they were separate galaxies. However, there was something odd about them. The core of the galaxy has two supermassive black holes, each with about 20 million solar masses! This means that there is more than double the usual amount found in similar galaxies.
The Hubble Space Telescope captured images of these nuclei which showed what appeared to be one of the growing brighter due to a massive outburst. Astronomers believe that one of the nuclei may have come from a merger with another smaller galaxy. The movement and interaction of stars in such an event could explain the twin nuclei phenomenon.
This ultra-violent behavior is thought to be caused by one of the black holes pulling in material from a circling companion star, said astronomer Frank Crenshaw at the National Radio Astronomy Observatory in Virginia, who led the team. In other areas around each black hole, there are what we call starvation regions where the gravity from the black hole is so strong that it overshadows all of the surrounding stars and disables them from moving any closer to it.
While this phenomenon has been seen before, the international team of scientists was all interested in this galaxy due to its distorted shape. A large amount of gas and dust is spinning around it at high speed, far beyond what would normally be seen in a normal galaxy. This may be because of gravitational interactions with one or both black holes, which can cause powerful winds that alter the shape of the surrounding gas.
Scientists are not sure if or how this merger of black holes will affect the galaxy itself. It is possible that it could change its shape again, but then again it may be too far gone to recover. The Hubble Space Telescope was able to see what appears to be a small satellite galaxy near one of the nuclei, which may have also been involved in the merger.
A more precise look at this galaxy will be done by NASA’s James Webb Space Telescope, which is due to launch in 2018. The addition of another powerful telescope should allow scientists to get a better view of this exquisite galactic activity.
Astronomers have many puzzles about our universe. One of the most perplexing is a galaxy called NGC 1097. It appears to have two active nuclei, rather than one as seen in other galaxies. Astronomers from Virginia used the National Radio Astronomy Observatory’s Very Large Array telescope to study this oddity more closely and four international groups also studied NGC 1097 with other powerful telescopes. The VLA’s image of the central region of NGC 1097 shows two bright sources, one on either side of a dusty lane. These are thought to be supermassive black holes with masses equivalent to around 20 million Suns each. A Hubble Space Telescope image reveals an inner ring that is probably being inflated by gas falling onto it and a companion galaxy to the east.