Today I return to last week’s Plan A, which was thwarted by the tragedy of the pandemic. The subject is supermassive black holes, objects that reside at the heart of virtually every elliptical and spiral galaxy, including our own. A new study has shown that they are able to influence the process of star formation in a vast region of space, including neighboring satellite galaxies.
A bit of context first. The Milky Way, our galaxy, has around 200 billion stars, of which the Sun is only one. These stars are distributed in spiral arms that contain clouds of gas that could form future stars in the future. In the central region there is a bulge with a greater stellar and gaseous concentration, and in the middle lies the supermassive black hole with a mass of 4.1 million suns, which is so compressed that its diameter is only 30 times larger than that of the sun .
There is a great deal of curiosity about what happens inside a black hole, since the known laws of physics “hit” there. But for astrophysicists, the most interesting thing is what happens outside. Stars and gas accumulate in the outer area of the black hole and are devoured by it over time. The object at the center of our galaxy is relatively calm (between meals), but there are many more active galactic hearts out there.
In these, the surrounding gas to be enveloped is accelerated, and the dynamics generate huge particle beams that are ejected at almost the speed of light in both directions of the axis of rotation of the black hole. For example, in the giant galaxy M87 (the same one whose central black hole was recently photographed) this jet is very visible and spans 5,000 light years.
It has long been speculated that jets emanating from the edge of the black hole hit the weak surrounding gas and influence star formation processes within the galaxy. That is, the central black hole is like a conductor that controls and modulates the production of new stars. Ignacio Martín-Navarro from the Astrophysics Institute of the Canary Islands and his colleagues wanted to test whether these processes can also affect neighboring satellite galaxies.
In an article published in Nature the conclusion came: yes. Using observational archival data from 124,000 satellite galaxies spread across more than 29,000 galactic systems, the researchers found that satellite galaxies located above and below the central galaxy’s black hole jets had less stellar production than the surrounding galaxies.
Finally, they tested whether the same effect occurred in a simulation called Illustris TNG, which reproduces on a computer the evolution of the universe on an intergalactic scale, based on fundamental laws of physics. And the effect is there too. In other words, these great conductors of the universe lead a much larger orchestra than previously thought.
This column is published in Folha Corrida on Mondays.
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