Mid-Sized Black Hole With 3:2 Flashing Ratio Discovered

Black holes have their own sizes and shapes. However, new research shows us that we are closer to seeing the existence of "medium" black holes.

Even though a number of medium black holes have been surmised, they have not been determined, according to the University of Maryland. But now scientists have found a new intermediate-mass black hole that is about 5,000 times the mass of the sun. It is between stellar mass black holes that are a few dozen times the mass of our sun and supermassive black holes a billion times the sun's mass.

"Currently astronomers are confident that smaller (masses of a few times our sun) and supermassive black holes (a few million to a few billion) exist in the Universe. This work strengthens the argument for the existence of a third class of black holes, i.e., the middle-weight black holes," lead author Dheeraj Pasham told HNGN.

The discovery of the intermediate-mass black hole candidate, called NGC1313X-1, is thought to be an ultraluminous X-ray source among the brightest in the neighbourhood. Even as the source of bright X-ray light in the remote universe is not clear, scientists feel that it can be traced back to "intermediate-mass black holes actively drawing in matter and producing X-ray radiation".

"To make an analogy with acoustic instruments, if we imagine that stellar mass black holes are the violin and supermassive black holes are the double bass, then intermediate-mass black holes are the violoncello," said co-author Francesco Tombesi, an assistant research scientist in UMD's Department of Astronomy who has a joint appointment at NASA Goddard via the Center for Research and Exploration in Space Science and Technology.

Scientists are trying to identify more ultraluminous X-ray sources with 3:2 flashing ratios, so more intermediate-mass black hole candidates can be discovered.

"NASA is soon to launch an X-ray satellite called Neutron Star Interior Composition ExploreR (NICER). NICER will be 1.5 times more sensitive than any of the current instruments to detect these 3:2 ratio X-ray flickering. Hence we anticipate to detect more such mid-sized black holes using the data from instruments on-board NICER. If we can build a census of these objects, we can start to learn more interesting things about the Universe like could these mid-sized black hole be the "seeds" for growing supermassive black holes when the Universe was very young .." Pasham told HNGN.

The findings were published in a recent edition of the Astrophysical Journal Letters.