One of the nearest supermassive black holes to Earth with active powerful outbursts has been discovered by a team of astronomers using NASA’s Chandra X-ray Observatory.
Messier 51 (M51) system of galaxies: the main panel shows M51 in visible light data from NASA’s Hubble Space Telescope (red, green, and blue); the box at the top outlines the field of view by Chandra in the latest study, which focuses on the smaller component of M51, NGC 5195; the inset to the right shows the details of the Chandra data (blue) of this region. Dr Schlegel and co-authors found a pair of arcs in X-ray emission close to the center of NGC 5195, which they interpret as two outbursts from the galaxy’s supermassive black. They estimate that it took about one to three million years for the inner arc to reach its current position, and three to six million years for the outer arc. Image credit: X-ray – NASA / CXC / University of Texas / E.Schlegel et al; optical – NASA / STScI.
This unusual object was found in the famous Messier 51 system of galaxies, which is located in the constellation Canes Venatici, approximately 26 million light-years away.
The system contains a massive spiral galaxy, NGC 5194 (also known as the Whirlpool Galaxy or M51), merging with the dwarf galaxy NGC 5195.
“Just as powerful storms here on Earth impact their environments, so too do the ones we see out in space. This black hole is blasting hot gas and particles into its surroundings that must play an important role in the evolution of the galaxy,” said team member Dr Eric Schlegel, of the University of Texas in San Antonio.
In the data from NASA’s Chandra X-ray Observatory, Dr Schlegel and co-authors detect two arcs of X-ray emission close to the center of NGC 5195.
“We think these arcs represent fossils from two enormous blasts when the black hole expelled material outward into the galaxy. This activity is likely to have had a big effect on the galactic landscape,” said Dr Christine Jones of the Harvard-Smithsonian Center for Astrophysics.
Just beyond the outer arc, the team detected a slender region of emission of relatively cool hydrogen gas in an optical image from the Kitt Peak National Observatory 0.9-m telescope.
This suggests that the hotter, X-ray emitting gas has ‘snow-plowed,’ or swept up, the hydrogen gas from NGC 5195’s center. This is a clear case where a supermassive black hole is affecting its host galaxy in a phenomenon that astronomers call ‘feedback.’
“We think that feedback keeps galaxies from becoming too large. But at the same time, it can be responsible for how some stars form, showing that black holes can be creative, not just destructive,” said team member Dr Marie Machacek, also of the Harvard-Smithsonian Center for Astrophysics.
The scientists believe the black hole’s outbursts may have been triggered by the interaction of NGC 5195 with its larger companion, NGC 5194, causing gas to be funneled toward the black hole.
They estimate that it took 1 to 3 million years for the inner arc to reach its current position, 3 to 6 million years for the outer arc.
“The black hole’s behavior may be a local example of events that commonly took place when the universe was much younger. That makes this observation potentially very important,” Dr Schlegel said.
The findings were presented January 5 at the 227th meeting of the American Astronomical Society (AAS) meeting in Kissimmee, Fla.
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Eric M. Schlegel et al. 2016. NGC 5195 in M51: Feedback ‘Burps’ after a Massive Meal? AAS 227, abstract # 118.04
