Galactic black hole emits massive flare

Posted by Kate Taylor

 NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) has taken its first look at the giant black hole at the center of our galaxy - and caught it right in the middle of a flare-up.

NuSTAR, launched just four months ago, is the only telescope capable of producing focused images of the highest-energy X-rays. For two days in July, it was teamed up with other observatories to observe Sagittarius A*, the black hole at the center of the Milky Way.

It spotted X-rays emitted by consumed matter being heated up to about 180 million degrees Fahrenheit, and originating from regions where particles are boosted very close to the speed of light.

"We got lucky to have captured an outburst from the black hole during our observing campaign," says Fiona Harrison, the mission's principal investigator at Caltech.

"These data will help us better understand the gentle giant at the heart of our galaxy and why it sometimes flares up for a few hours and then returns to slumber."

While active black holes tend to gobble up stars and other fuel around them, Sgr A* appears for some reason to have a very small appetite. As it's the consumption of fuel that leads to flare-ups, Sgr A* is pretty quiet compared to the giant black holes at the centers of other galaxies.  

Scientists say the NuSTAR data, when combined with the simultaneous observations taken at other wavelengths, will help them better understand the physics of how black holes 'snack' and grow in size.

"Astronomers have long speculated that the black hole's snacking should produce copious hard X-rays, but NuSTAR is the first telescope with sufficient sensitivity to actually detect them," says NuSTAR team member Chuck Hailey of Columbia University.