Thursday, April 6, 2017

Capturing Our Galaxy's Black Hole Event Horizon

This time, we're not talking about the black holes in the Oval Office and House Intelligence Committee.

Led by Shep Doeleman, an astronomer at the Harvard-Smithsonian Center for Astrophysics, astronomers around the world will be looking to capture an image of the event horizon of the black hole at the center of our Milky Way galaxy:
... On Wednesday night, a battalion of 120 astronomers working at eight observatories on four continents will mobilize in an unprecedented effort to image the black hole at the center of the Milky Way, a body named Sagittarius A*. By combining observations from points across the globe, they'll create a virtual observatory the size of Earth itself. The “Event Horizon Telescope,” they call it. 
If all goes according to plan, the EHT should capture the dark silhouette of Sagittarius A* against the hot, glowing material that surrounds it, offering the first-ever glimpse at a black hole's event horizon. The resulting snapshot could confirm our understanding of the laws of the universe — or upend it. [snip]
Over five nights during a 10-day window beginning Wednesday, the eight telescopes of the EHT will swivel as one toward the center of the galaxy. Scientists in Chile's Atacama Desert, on a volcano top in Hawaii, at the frozen expanse of the South Pole and in the high, dry mountains of Arizona, Mexico and Spain will be ready to catch the data. If conditions are exactly right at each location — skies clear, instruments working — then Doeleman will give the signal to start observing. 
In addition to Sagittarius A*, the EHT will target a second, even more massive black hole in neighboring galaxy M87. 
Once they get their five nights of observations, the astronomers around the globe will deliver their findings to supercomputers at the Massachusetts Institute of Technology and the Max Planck Institute in Germany. Doeleman expects to have two to three petabytes of data to look through — equivalent to the storage capacity of about 10,000 MacBooks. It will take the researchers months, if not years, to analyze all the findings. 
Here's where they'll be training their telescopes:

The black hole Sagittarius A* appears as a large bright spot in the orange cloud of dust at the center of the Milky Way. (D. Haggard et al. (NASA/CXC/Amherst College)

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