Sagittarius A* (Sgr A*) is a bright bloom of radio waves thought to be the black hole in the center of the Milky way. In this x-ray map of the galactic center, researchers discovered two large ‘chimneys’ of plasma leaking out of the Sgr A* region, and the apparent dumping of hot matter in two huge gas bubbles, so-called Fermi bubbles.
(G. Ponti et al.)
The supermassive black hole at the center of our milky way galaxy is a bit like the fireplace in the centre of a cosy pub. It is a light, warm gathering place around which all life in the Milky way swirls — and, according to a new survey published today (Mar. 20) in the journal Nature, is the perhaps even a chimney or two.
In a recent study of the X-ray emission seething of the Milky way, the galactic center, the researchers noticed two unusual structures that were never previously described. Separate columns of superhot, X-ray-emitting plasma was found to be billowing from the galactic centre, rising north and south as it flows for hundreds of light years in both directions.
“We call this the” chimneys,” lead study author Gabriele Ponti, a researcher at the National Institute for Astrophysics (INAF) in Italy, told live Science. “Look, we see clear evidence for a strong outflow of plasma from the galactic center.” [The 12 Weirdest Objects in the Universe]
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Ponti and his colleagues found this evidence by analyzing more than 750 hours of X -ray observations by the XMM-Newton and Chandra telescope. These observations helped the team to create an X-ray map of the center of the Milky way (see above), including the near-symmetrical chimney plumes, originating from both sides of the Sagittarius A*, the bright source of radio waves, believed to shroud our galaxy’s supermassive black hole.
Both the northern and southern chimneys to extend over 522 light-years about the galactic center, and any warmer and denser the closer they are to Sagittarius A*. It seems clear that this explosion of heat and matter are the result of a large outflow from the galactic center, Ponti and colleagues wrote, although the exact origin is unknown. The available evidence points to two possibilities: the outflow is caused by the supermassive black hole itself (which may be slingshotting some matter in space, even as it gobbles large parts of the nearby gas and dust) or else by means of periodic supernova explosions take place in the entire galaxy-central cluster.
“The data supports both of these scenarios,” Ponti said.
Blowing cosmic bubbles
The chimneys’ final destination, meanwhile, seems clearer than their country of origin.
In their X-ray map, the researchers saw that the northern and southern chimneys, which extend to the bases of two gigantic structures known as the Fermi-bubbles — in fact, two gigantic cavities of gas and cosmic rays cut from the galactic center by millions of years of activity.
These bubbles start about 326 light-years above each side of the galactic center, which coincides with the tips of the chimneys. In contrast to the chimneys, but the bubbles stretch on for tens of thousands of light years, towering high above the Milky way, such as two rooms of a large hourglass. Together, the two spheres occupy about as much space as the galaxy itself, Ponti said. (Don’t be too hard for them though; because they are composed mainly of gamma-rays, the bubbles are invisible to the naked eye.)
Since 2010, scientists have known of our galaxy blowing space bubbles and thinking that they were probably made by a number of turbulent case at the galaxy’s center several million years ago. However, according to the Ponti, the discovery of the galactic chimneys is the first direct connection between this huge, gaseous spheres and the Milky way in the relatively small core.
“The chimneys are the exhaust connecting the activity of the galactic center with the Fermi bubbles,” Ponti said.
Further study of the chimneys can reveal a more precise origin of the Fermi bubbles. The next step, Ponti said, is imaging a still larger part of the galactic center to see, for example, if the chimney flow seems localized about the galaxy’s supermassive black hole, or if it is spread over a larger cluster of stars. Either way, the heart in the center of the milky way will a fire burn for us, perhaps greater than anyone imagined.
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Originally published on Live Science.