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Posted Nov 7, 2018
The huge elliptical galaxy Abell 2597 located in the heart of one of the most massive galaxy clusters in the universe has revealed a cosmic secret to the evolution and life span of massive galaxies.
"The evolution of galaxies can be quite chaotic, and large galaxies like this one tend to live harder and die young," says Dr. Timothy Davis, an Ernest Rutherford Scholar and lecturer here at Cardiff University in the Department of physics and astronomy. which focuses on the evolution of galaxies and how they come together from the high redshift cosmic soup to become the beautiful and diverse populations we see around us in the local universe.
For the first time, says Davis, we were able to observe the complete cycle of a supermassive black hole fountain, which governs this process, extending the life of galaxies by tapping into vast reserves of cold molecular gas, and then spraying again in a current cycle.
With the help of Chile's Large Millimeter / Subillimeter Array (ALMA), the team, made up of researchers from Cardiff University, observed a supermassive black hole acting as a "monumental fountain" in the middle of a galaxy, named Abell 2597, more than a billion light years from Earth.
In the Abell ESO image above 2597, the background (blue) comes from NASA / ESA's Hubble Space Telescope. The foreground (in red) represents ALMA data showing the distribution of carbon monoxide in and around the galaxy. The drop-down box displays the ALMA data of the "shadow" (black) produced by the absorption of millimeter light emitted by the electrons whizzing around the strong magnetic fields generated by the supermassive black hole of the galaxy. The shadow indicates that cold clouds of molecular gas are raining on the black hole.
The evolution of the galaxy can be chaotic and disordered, but it seems that jets of cold gas emanating from the region surrounding supermassive black holes can act to calm the storm. This is according to an international team of scientists who provided the first clear and convincing evidence of this process in action.
According to Cardiff researchers, this whole system works through a self-regulating feedback loop. The incoming material feeds the fountain when it "drains" toward the central black hole, such as water entering the pump from a fountain. This gas then causes intense activity of the black hole, which launches high speed jets of superheated materials that spring from the galaxy.
As it moves, this material pushes gas clusters and gas streamers into the expansive halo of the galaxy, where it eventually falls back onto the black hole, triggering the process again.
By studying the localization and motion of carbon monoxide (CO) molecules with ALMA, which shine under millimetric light, the researchers were able to measure the movement of the gas that falls to the black hole.
It is from these plumes of gas that new stars are formed in galaxies and researchers believe that the process they observed could be common to the entire Universe and, more importantly, could be crucial for the development of gigantic galaxies like this one.
"The supermassive black hole in the center of this giant galaxy acts as a mechanical" pump "in a fountain," said Grant Tremblay, an astrophysicist at Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and lead author of the journal. . "This is one of the first systems in which we find clear evidence of a supply of cold molecular gas to the black hole and a flow out of or out of the jets thrown by the black hole."
The Daily Galaxy via Cardiff University and The Conversation
Image credits: NRAO / AUI / NSF; D. Berry and image at the top: B. Saxton (NRAO / AUI / NSF) / G. Tremblay et al./NASA/ESA Hubble / ALMA (ESO / NAOJ / NRAO)
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