From NYT: “A Teensy Black Hole, Just 200,000 Miles Wide”

New York Times

The New York Times

August 14, 2015

An artist’s illustration of the black hole at the center of dwarf galaxy RGG 118. Credit Chandra X-ray Observatory

For a monster it’s pretty cute.

Buried in a smush of stars known as RGG 118 — and noticeable only by a plaintive squeal of X-ray radiation — astronomers have discovered a new black hole. By the standards of normal life it’s not so small, a pit in space-time 200,000 miles across into which the equivalent of 50,000 suns have disappeared. But on a cosmic scale it’s not so big.

Almost every galaxy, like the Milky Way, has a supermassive black hole millions or billions of times as massive as the sun sitting at it center. The bigger the galaxy, the more massive the black monster at its heart. Nobody knows why.

The new black hole is the first one found in a dwarf galaxy. RGG 118, as it is elegantly named, is 340 million light-years away and about a hundredth the mass of our own Milky Way, whose central black hole weighs some 4 million suns.

A team from the University of Michigan and Princeton, led by Vivienne Baldassarre, a Michigan graduate student, found and measured it by using NASA’s Chandra X-Ray Observatory and an optical telescope in Chile* to chart the speeds of stars and gas swirling around in the small galaxy.

NASA Chandra Telescope

Observing the behavior of such a teensy, so to speak, black hole, Ms. Baldassare and her colleagues hope, will help them understand where the monstrous black holes found in regular galaxies come from and how they grow so big. Some astronomers speculate that they are seeded from giant clouds of primordial gas, or the collapse of gargantuan stars that inhabited the dawn of time, and then grew by merging with other black holes as galaxies collided during the rough and tumble days of the early universe.

The RGG 118 black hole is like finding a preteenager on the verge of all this. In the fullness of cosmic time, it could grow into a true monster.

*optical telescope in Chile went unnamed in the article. Bad taste.

See the full article here.

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