An immense jet of material spewing out of a black hole 12 million light-years away is hitting something in space, but astronomers aren’t exactly sure what.
The structure popped up in a recent ultra-deep X-ray image taken by NASA’s Chandra X-ray Observatory—in fact, the deepest X-ray image ever taken of the galaxy, called Centaurus A. The unknown blockade, dubbed C4, is emitting plenty of X-rays. A recent astronomical team’s findings surrounding Centaurus A and the surprise obstruction were published in The Astrophysical Journal.
Black holes are areas of spacetime with gravity so intense that light cannot escape them beyond a point called the event horizon. Black holes can be anywhere between several times the mass of our Sun (barring the existence of primordial black holes) to many billions of times the Sun’s mass.
But black holes have other extreme physics at work; the objects sometimes emit jets of particles moving at nearly the speed of light. These jets can catalyze stellar eruptions—literally, they can cause stars to explode—and they can also be staggeringly large; in September, a group of astronomers identified black hole jets 140 times longer than the width of the Milky Way.
C4 has V-shaped arms, visible in the Chandra image (shown below; the top image is a wide-field shot that doesn’t show C4). The apparent V-shape is caused by a jet from the black hole hitting the object.
C4, as seen in a Chandra image. Image: NASA/CXC/SAO/D. Bogensberger et al.; Image Processing: NASA/CXC/SAO/N. WolkThough the arms of the V-shape emanating from C4 appear quite small—especially compared to the immense jet on the other side of the black hole—they each stretch 700 light-years in length. For reference, and as noted in the Chandra X-ray Observatory release, the black hole’s jet is 30,000 light-years long, and the nearest star to the Sun is four light-years away. All this is a reminder that the universe is gargantuan.
It’s not the first time a black hole jet has smacked into something—in fact, astronomers previously saw the Centaurus A jet hitting objects, perhaps stars or gas clouds. But C4’s V-shape is irregular, and may be related to the kind of object the jet is striking or the way in which the jet is coming into contact with the object.
Black hole jets are some of the flashiest astrophysical phenomena around and evidently have plenty more tricks up their sleeves. While we may not know what C4 is anytime soon, rest assured that researchers are on the case.
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