Saturday, December 5, 2015

Earth-Sized Telescope Finds Clue To Black Hole Growth

For the first time, astronomers have detected evidence of magnetic fields near Sagittarius A*, the black hole at the centre of the Milky Way, taking the study of black hole growth from theoretical expectation to empirical fact.

Sagittarius A* 
Sagittarius A*.jpg
Credit: NASA's Chandra X-Ray Observatory

A new discovery, published today in the journal Science, has greatly deepened our understanding black holes, which are believed to be the gravitational engines at the centres of most galaxies, including our own.

Using an array of telescopes that spans the globe, astronomers detected evidence of magnetic fields near Sagittarius A*, the 4.5-million-solar-mass black hole at the centre of the Milky Way.

Time-Lapse of Supermassive Black Hole Sagittarius A*



Credit; NASA
Decades of theoretical work, including enormous computer simulations, have painted a picture of how strong horizon-scale magnetic fields near the black hole contribute to its growth. Now that this international collaboration has discovered high levels of polarization in the radio emissions from Sagittarius A*, physicists have proof that these magnetic fields indeed exist.

Were these magnetic fields not there, “a lot theoretical astrophysics would have to go back to the drawing board,” says Avery Broderick, an Associate Faculty member at Perimeter Institute for Theoretical Physics, jointly appointed at the University of Waterloo.

Researchers achieved this new finding using the Event Horizon Telescope – an interconnected array of millimeter-wavelength telescopes located around the world. Together, they form an Earth-sized telescope capable of extremely high resolution, which, in the near future, will enable astronomers to image the event horizon of a black hole for the first time in human history.

Fcused views of the supermassive black hole at the heart of the Milky Way in high-energy X-rays.
File:Pointing X-ray Eyes at our Resident Supermassive Black Hole.jpg
Credit; NASA NuSTAR

“There are now enough telescopes in the array, in principle, to make images in the next couple of years,” Broderick added. “This might be the point, like the turn of the last century, when all of a sudden the puzzle pieces click into place.”

Those images will enable astrophysicists to transform our understanding of how black holes grow, how they interact with their surroundings, and even the nature of gravity.

“We are on the cusp of a true first in astronomical exploration,” says Avery Broderick. “We fully expect to have imaged a black hole’s event horizon in a matter of years. This would be an incredible accomplishment, not just for science, but humankind.”



Contacts and sources: 
Eamon O'Flynn
Perimeter Institute for Theoretical Physics 

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