It’s not everyday that you get to see what’s on a black hole’s dinner menu. The European Space Agency’s Herschel space observatory has spotted hot molecular gas that may be circling or falling towards the supermassive black hole located at the center of our Milky Way galaxy.
According to a news release from the ESA, the black hole resides in a region called Sagittarius A. It has a mass approximately four million times that of our Sun and sits about 26,000 light-years away from the Solar System.
Though 26,000 light-years seems like a great distance, which it is, it is still several hundred times closer to us than any other galaxy with an active black hole lurking at its center. According to astronomers, this makes it a great place to examine the environment around black holes.
Astronomers are unable to see this region of our Milky Way galaxy in visible wavelengths because of large amounts of dust. However, they are able to see through the dust using far-infrared wavelengths.
Herschel has picked up a number of simple molecules at the Milky Way’s center, including carbon monoxide, water vapor and hydrogen cyanide. These molecules have helped astronomers learn a lot about the interstellar gas the envelopes the black hole.
According to lead author Javier Goicoechea of the Centro de Astrobiología, ESA’s Herschel has analyzed the far-infrared emission within just one light-year of the supermassive black hole, “making it possible for the first time at these wavelengths to separate emission due to the central cavity from that of the surrounding dense molecular disc.”
Astronomers were stunned to discover just how hot the molecular gas in the Galaxy’s center becomes. They learned that some of the molecular gas becomes as hot as 1000ºC, which is a lot hotter than normal interstellar clouds.
According to the astronomers, the intense ultraviolet radiation coming from a cluster of massive stars that reside close to the Galactic Center can’t be the only reason for the high temperatures.
The astronomers posit that emissions from powerful shocks in highly-magnetized gas in the region may also explain the high temperatures. These shocks can be produced in collisions between gas clouds, or in material traveling at high speed from stars and protostars.
“Our Galaxy’s black hole may be cooking its dinner right in front of Herschel’s eyes,” says Goicoechea.