The black hole, located in the galaxy NGC 4395, is only about as massive as 50,000 of our suns. Thats not quite as big as other supermassive black holes, which tend to be millions to billions of times as massive as our sun, but its a thousand times grander in scale than smaller stellar black holes.

According to the astronomers who detected the object with Japans Advanced Satellite for Cosmology and Astrophysics (ASCA), the black hole seems to be acting like a supermassive black hole, despite its size. Its sucking up matter at roughly the same rate as its much larger (and seemingly less hungry) relatives, they said.

"The small black hole in this galaxy is working hard to rival bigger black holes of low efficiency," said Kazushi Iwasawa, a researcher at the Institute of Astronomy in England, and one of the discoverys contributors.

Black holes are regions of space so dense, not even light can escape their gravitational pull. As a black hole gobbles up gas, dust and even entire stars, the incoming matter gets so hot, it gives off high-energy radiation as it plunges into the hole. This energy includes X-rays, which are detectable by telescopes in near-Earth orbit.

Until now, scientists had speculated that black holes residing in galaxies with dim cores such as NGC 4395 were either too old or too small to quickly eat up lots of material, as more massive black holes do on a regular basis. But now it seems that "mid-mass" black holes (a new nickname for the smallest type of supermassive black holes) may simply be more efficient matter-eaters.

"We now see that the nuclear source in NGC 4395 is a scaled-down version of black holes found in the most luminous of galaxies," said, Andrew Fabian, another Institute of Astronomy researcher who worked on the discovery. "Everything is the same, only it is smaller."

As a result, some astronomers now think that the total output of X-rays from accreting matter may therefore be more a product of how massive the black hole is, rather than of the luminosity of the region surrounding the black hole, as it once was thought.

"NGC 4395 hosts the least luminous and nearest active nucleus known," said Fabian. "This [discovery] shows that mid-mass black holes behave like their more massive and less massive cousins."

According to Iwasawa and Fabian, this new change in thinking will be extremely important for future studies of the relationships between black holes and the galaxies they reside in. Their results will be published in an upcoming issue of the Royal Astronomical Societys Monthly Notices.