Gnome galaxies are a home for big black holes

Anew hint towards finding out the early history of galaxy formation comes up as the astronomers discover 13 new black holes in some dwarf galaxies which are not more than a billion light-years away from our planet.

These gnome galaxies are at least are 100 times smaller if compared to our milky way. They are identified as the smallest star system to host such humungous black holes. The researchers calculate that these black holes would be as big as 400,000 times of mass as to the Sun.

“We hope that studying them and their galaxies will give us insights into how similar black holes in the early Universe formed and then grew, through galactic mergers over billions of years, producing the supermassive black holes we see in larger galaxies today, with masses of many millions or billions of times that of the Sun,” said Amy Reines of Montana State University.

Reines and her fellow colleagues used the National Science Foundation’s Karl

G. Jansky Very Large Array (VLA) to make the discovery, which they are reporting at the American Astronomical Society’s meeting in Honolulu, Hawaii.

Reines and her collaborators used the VLA to discover the first massive black hole in a dwarf starburst galaxy in 2011. That discovery was a surprise to astronomers and spurred a radio search for more.

“The new VLA observations revealed that 13 of these galaxies have strong evidence for a massive black hole that is actively consuming surrounding material. We were very surprised to find that, in roughly half of those 13 galaxies, the black hole is not at the centre of the galaxy, unlike the case in larger galaxies,” Reines said.

The scientists said this indicates that the galaxies likely have merged with others earlier in their history. This is consistent with computer simulations predicting that roughly half of the massive black holes in dwarf galaxies will be found wandering in the outskirts of their galaxies.