The Milky Way is not very active, as far as galaxies are concerned. Each year, it produces regarding three to four new stars in its entire spiral body.
According to Russia Today, however, there are some quieter galaxies – elliptical galaxies, in which most of the star formation has long stopped. And in these galaxies, no stars or very few of them younger than a certain age might be found, indicating that at some point most star formation stopped abruptly, leaving the galaxy to slowly wink over the ages, star following star..
The exact way star formation is halted in these smooth, almost featureless galaxies remains a mystery, but astronomers believe it has something to do with the supermassive black holes at the center of each galaxy. Now, an international team of astronomers led by Kei Tu, from the Graduate University of Advanced Studies, has researched, SOKENDAI In Japan, in the early universe to see if this is the case.
Using some of the most powerful telescopes in the world, they have collected data with multiple wavelengths of light to identify galaxies whose light has traveled from 9.5 billion to 12.5 billion years through the gulf of spacetime – ancient galaxies like those elliptical galaxies closest to us in space and time, for which star formation was at regarding to collapse.
The first step was to use optical and infrared data to identify galaxies in which star formation continues, and those in which star formation has stopped.
The next step was to use X-ray and radio data to determine the activity of the supermassive black hole. This is the mechanism by which astronomers believe star formation can be suppressed. When a supermassive black hole activates, it devours massive amounts of matter from the space around it. This process is chaotic and violent and produces what is known collectively as ‘feedback’“.
We all know that nothing can appear beyond the event horizon of a black hole, but the space around it is a different matter. Material orbits around the black hole, like water circulates around a drain; Gravity and friction generate intense radiation that ignites across the universe.
Another form of feedback takes the form of jets emanating from the black hole’s polar regions. It is believed that material outside the event horizon accelerates along the black hole’s external magnetic field, to be released from the poles in the form of powerful, focused plasma jets that travel at a large rate of the speed of light..
Finally, active supermassive black holes generate strong winds that sweep their galaxies. All three forms of feedback – radiation, jets and wind – are thought to heat and push the cold molecular gas required to form young stars..
Across such vast distances, galaxies are hard to see; It’s too small and too faint from our here and now. So the researchers had to “stack” galaxies together in order to confirm the radio and X-ray light that are telltale signs of a supermassive black hole that has been active for all those billions of years..
The team found that the “excess” X-rays and radio signal are too powerful to be explained by stars alone in galaxies with little or no star formation. This signal is best explained by the presence of an active supermassive black hole. Moreover, the signal was not evident in galaxies with continuous star formation.
The researchers conclude that this indicates that it is very plausible that an active supermassive black hole may play a role in the sudden death of these mysterious ghost galaxies..
They said future research may help shed light on the detailed physics of this mysterious process.
