South Korean astronomers have discovered for the first time strong evidence of a medium-sized black hole that is 10-thousand times the mass of the Sun.
'Intermediate mass black holes' usually measure less than a million times the mass of the Sun, while 'supermassive black holes' are more than a million times, and sometimes even a billion times, the mass of the sun.
Astronomers have long debated the existence of mid-sized black holes in the center of galaxies, but a research team at Seoul National University has finally discovered one in the dwarf galaxy NGC 4395, some 14-million light years away.
"There has been controversy over the existence of black holes that are smaller than supermassive black holes, which are usually heavier than 1-million times solar mass. But we have discovered one that is 100 times smaller than those, so now it's evident. () Also, the newly discovered black hole can show how supermassive black holes could have originated and developed."
To calculate the mass, the astronomers measured velocity of gas clouds around the black hole and the distance between them. To measure the distance, they used the travel time of light bouncing off material around the galaxy's nucleus.
"We also used the 'light echo effect' to measure how long it takes for the light to reach the gas clouds from the black hole to calculate the distance."
The latest findings were published in the journal Nature Astronomy this week. Dr. Woo said he plans to further shed light on the development of supermassive black holes based on this latest discovery, as it can serve as a strong clue to how they originated and developed.
Yoon Jung-min, Arirang News.