ALMA Telescope Spies Two Supermassive Black Holes On A Collision Course As Their Host Galaxies Smash Into Each Other

Wednesday, 08 January 2020 - 9:32AM
Black Holes
Wednesday, 08 January 2020 - 9:32AM
ALMA Telescope Spies Two Supermassive Black Holes On A Collision Course As Their Host Galaxies Smash Into Each Other
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Artist impression of the merging galaxy NGC 6240. Credit: NRAO/AUI/NSF, S. Dagnello.
The Atacama Large Millimeter Array telescope in Chile just imaged two supermassive black holes being hurled towards each other as their galaxies merge, according to a release from the National Radio Astronomy Observatory. Galaxy NGC 6240 is the result of this galactic merger; it's in the constellation Ophiucus, about 400 million light-years away. It's a good distance to be: Astronomers have been studying the two supermassive black holes that are on track to merge into one super supermassive black hole with exponentially greater gravitational force.


The Atacama Large Millimeter Array – or ALMA – is a fleet of 66 finely tuned telescopes in the Chilean desert. Although ALMA is technically a radio telescope, it actually studies a very particular kind of light. Millimeter and submillimeter light have a wavelength that is about 1,000 slower than visible light. It's how we study cold or distant objects. By observing the millimeter and submillimeter light given off by the dust clouds surrounding these two black holes, we can get some idea of their size and structure.


"The key to understanding this galaxy system is molecular gas," said Ezequiel Treister of the Pontificia Universidad Católica in Santiago, Chile. "This gas is the fuel that is needed to form stars, but it also feeds the supermassive black holes, which allows them to grow."


NRAO shared this photo of NGC 6240 as seen with ALMA (top right) and the Hubble Space Telescope (combined image on the left and zoomed in on the bottom right). The molecular gas is blue, and the black holes are two red dots.





(Credit: ALMA (ESO/NAOJ/NRAO), E. Treister; NRAO/AUI/NSF, S. Dagnello; NASA/ESA Hubble – CC BY 3.0)


Treister continued, "We see a chaotic stream of gas with filaments and bubbles between the black holes. Some of this gas is ejected outwards with speeds up to 500 kilometers per second. We don't know yet what causes these outflows."


Loreto Barcos-Muñoz of the NRAO in Charlottesville, Virginia, added, "This galaxy is so complex, that we could never know what is going on inside it without these detailed radio images," said Loreto Barcos-Muñoz of the NRAO in Charlottesville, Virginia. "We now have a better idea of the 3D-structure of the galaxy, which gives us the opportunity to understand how galaxies evolve during the latest stages of an ongoing merger. In a few hundred million years, this galaxy will look completely different."


(Cover image: NRAO/AUI/NSF, S. DagnelloCC BY 3.0)
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