New twists on galaxy’s black hole

[Starlyte]

The supermassive black hole at the center of our Milky Way galaxy is heftier than thought and rotates at an amazing clip, new research shows.

As hot gas falls into the Milky Way's supermassive black hole, the energy is converted into bursts of radiation. The infrared emissions may accompany blobs of gas ejected from the disk (purple) or come from sparks that occur randomly in the accreting gas (yellow).

FOR YEARS scientists said the black hole contained about 2.6 million times the mass of the sun. They now believe the figure is somewhere between 3.2 million and 4 million solar masses.

And a new study suggests all that mass, confined to an area about 10 times smaller than Earth’s orbit around the sun, spins around about once every 11 minutes. The sun, in comparison, takes about a month to make a revolution on its axis. Earth spins once every 24 hours.

Black holes can’t be seen or measured directly, because light passing near them gets trapped. So astronomers measure a black hole’s mass by observing the orbital speed of nearby stars.

The new mass estimate was made by two separate groups, one at the University of California at Berkeley, and another at the University of California at Los Angeles, Berkeley physicist Reinhard Genzel told Space.com.

More interesting, perhaps, is what appears to be a precise measurement of the supermassive black hole’s spin rate made by Genzel’s group.

Other studies have shown compelling evidence for the rotation of less massive black holes, formed when stars collapse. That’s no surprise to astronomers, since these stellar black holes would logically retain the rotation of their progenitor stars. The first solid evidence for a spinning stellar black hole emerged more than two years ago.

Only hints of spin have been noted from supermassive black holes, each of which is thought to form and evolve hand-in-hand with the development of the galaxy in which it sits.

Full Article LINK