This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Galaxies are enormous and hold hundreds of billions of stars. These stars form from cold, dense gas.
Every large galaxy, including the Milky Way, is wrapped in a huge envelope of gas called the circumgalactic medium, or CGM. This reservoir of raw material stretches 10–20 times the size of the visible portion of the galaxy. The gas eventually cools, moves inward and clumps together to form stars.
Thus, the CGM plays a key role in shaping stars, planets and even life within a galaxy. But astronomers have long puzzled over why, given how much star-forming gas surrounds them, galaxies don't have even more stars. What is keeping the fuel from cooling down and forming those stars?
A new study led by astronomers Sanchayeeta Borthakur of Arizona State University (ASU) and Namrata Roy, now at the Raman Research Institute (RRI), found evidence that narrow jets of heated plasma blasted out by supermassive black holes at galaxies' centers can affect gas beyond the visible galaxy and may shape its future. The jets may disrupt the gas that galaxies need to keep growing. Their research is published in the Astrophysical Journal Letters.
"This is a pathbreaking result that solves the long-standing mystery of how black holes influence galaxies, their stars and life as we know it!" said Borthakur, an associate professor in ASU's School of Earth and Space Exploration. "This work opens a new direction to explore further the intricacies of the connection between the supermassive black holes trillions of miles from where we are to how we came to be here." When a black hole actively feeds on gas, it can release enormous energy that heats the surrounding gas. Even though these black holes can be powerhouses of energy, they are roughly the size of our solar system.
Their host galaxies, on the other hand, can hold about 100 billion such solar systems. "The surprising question is: how can something so small energetically impact something so enormous?" said Roy, an assistant professor at RRI and former ASU Exploration Prize Postdoctoral Fellow. One way to envision it is to think of an ant leaving its impression hundreds or thousands of kilometers away.
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