Astronomers have discovered a tiny galaxy that ironically hides a supermassive black hole, a region of space with gravity so strong even light cannot escape.
On Wednesday, the National Aeronautics and Space Administration (NASA) revealed that the agency's Hubble Space Telescope, one of the biggest and most versatile space telescope used as a research tool for astronomy, has allowed scientists to discovered a new dwarf galaxy with diameter about 1/500th of that of our own Milky Way.
"Dwarf galaxies usually refer to any galaxy less than roughly one-fiftieth the brightness of the Milky Way," explained Anil Seth, from the University of Utah in Salt Lake City, lead author of the study describing the findings, which was published in the journal Nature on Sept. 17.
Seth said that these tiny galaxies which are only several hundreds to thousands of light years in diameter are far smaller compared with the 100,000-light-year diameter of the Milky Way but they are more abundant in the universe.
"These are found primarily in galaxy clusters, the cities of the universe," Seth said.
At the core of the newly found galaxy called M60-UCD1 is what NASA describes as "supermassive" or the largest of black holes, which have masses equivalent to more than 1 million suns. M60-UCD1's black hole has five times the mass of Sagittarius A, the black hole found at the center of our galaxy. Sagittarius A has a mass equivalent to that of about 4 million suns while the mass of M60-UCD1's black hole is estimated to be equivalent to 21 million suns.
Jay Strader, an assistant professor of physics and astronomy at the Michigan State University and member of the team that discovered the black hole, said that the findings suggest supermassive black holes may exist more commonly in less-massive galaxies than previously believed.
"This means that the 'seeds' of supermassive black holes are more likely to be something that occurred commonly in the early universe," Strader said.
Seth and colleagues wrote that the supermassive black hole found in M60-UCD1 suggests that the galaxy is a ripped remnant of another larger galaxy that has broken apart during a violent event such as when it collided with other galaxies.
"The high black hole mass and mass fraction suggest that M60-UCD1 is the stripped nucleus of a galaxy," the scientists wrote. "Our analysis also shows that M60-UCD1's stellar mass is consistent with its luminosity, implying a large population of previously unrecognized supermassive black holes in other ultra-compact dwarf galaxies."
