The beautiful spiral galaxy visible in the center of the image is known as RX J1140.1+0307, a galaxy in the Virgo constellation imaged by the NASA/ESA Hubble Space Telescope, and it presents an interesting puzzle. At first glance, this galaxy appears to be a normal spiral galaxy, much like the Milky Way, but first appearances can be deceptive!
It is commonly accepted that the center of nearly every galaxy contains a supermassive black hole. Their size often defies imagination, with millions, sometimes billions, of solar masses. Even our home galaxy, the Milky Way, has a four million solar mass black hole located at its center, about 27,000 light years from Earth. Most of these black holes are dormant, but a few per cent are 'active' meaning that they are devouring material from their host galaxy, forming an accretion disc that feeds the black hole.
As the material spirals through the disc toward the event horizon, it gains fantastic speed and releases vast amounts of energy. As a result, some of the disk material does not fall in because its speed achieves escape velocity. This material is slung around to one of the poles and expelled as a powerful jet traveling near the speed of light.
The size of a supermassive black hole appears to have a direct correlation to its host galaxy. Almost a decade ago, researchers calculated that the mass of a supermassive black hole appeared to have a constant relation to the mass of the central part of its galaxy, known as its bulge. This 1 to 700 relationship supports the notion that the evolution and structure of a galaxy is closely tied to the scale of its black hole.
The largest supermassive black hole ever found contains up to 21 billion times the mass of the sun, and resides in the incredibly dense Coma Cluster, which includes more than 1,000 identified galaxies.
The close-up view shown above was taken by the NASA Hubble Space Telescope shows Galaxy NGC 1068 at the doughnut disk of gas and dust surrounding its supermassive black hole in the clearest form yet. NuSTAR's high-energy X-rays eyes were able to obtain the best view yet into the hidden lair of the galaxy's central, supermassive black hole. The most massive black holes in the universe are often encircled by thick, doughnut-shaped disks of gas and dust. This deep-space doughnut material ultimately feeds and nourishes the growing black holes tucked inside.
The Milky Way galaxy, like most large galaxies, has a supermassive black hole at its center, but some galaxies are centered on lighter, intermediate-mass black holes. RX J1140.1+0307 shown below is such a galaxy -- in fact, it is centered on one of the lowest black hole masses known in any luminous galactic core.
What puzzles scientists about this particular galaxy is that the calculations don't add up. With such a relatively low mass for the central black hole, models for the emission from the object cannot explain the observed spectrum. There must be other mechanisms at play in the interactions between the inner and outer parts of the accretion disk surrounding the black hole.
European Space Agency
Image Credit: ESA/Hubble & NASA, Acknowledgement: Judy Schmidt