Category: very large array

The Smallest Galaxies Have Off-Kilter Black Holes, But Astronomers Know Why

“Over 100 dwarf galaxies are now known to possess these black holes, with the first verified one discovered in 2011. However, solely finding radio emissions isn’t enough: active black holes and star-formation bursts can create that signal. Researchers led by Dr. Amy Reines just conducted the first large-scale radio survey looking for black holes in dwarf galaxies. Using the Very Large Array, her team surveyed 111 dwarf galaxies, and found 13 of them that showed evidence for massive black holes. Remarkably, approximately half of the black holes were not located at the galaxy’s centers, but were significantly off-kilter.”

When we examine the supermassive black holes we find in the Universe, they’re pretty much always found at the centers of galaxies. However, these are for black holes of millions-to-billions of solar masses and galaxies comparable in mass (or even greater than that) to the Milky Way. But dwarf galaxies, the majority of galaxies in the Universe, are predicted to have much smaller black holes. The first large survey of these galaxies was just undertaken, revealing a population of dwarf galaxies with black holes. 

But half of them are located off-center, rather than at the center! Why is that? Astronomers know, and you can too!