Black holes can prevent young stars from forming through the emission of vast quantities of particles. These tiny objects travel at nearly the speed of light, emitting radio waves that can interfere with the formation of new stars in older galaxies, according to a new study.
Massive black holes exist at the centers of most, if not all, galaxies. Stellar formation is rare in ancient collections of stars, and a team of astronomers now believes they know the reason this relationship is seen. It is possible that these emissions of particles, radiating radio waves, are interfering with the production of new stars by heating the interstellar medium from which they form.
Johns Hopkins University researchers used one of the standard tools of astronomers in a novel way in order to study the ancient galaxies. The Sunyaev-Zel'dovich effect signature, usually refereed to as the S-Z effect, is a measurement of how high-energy electrons within heated gas interacts with the cosmic microwave background (CMB) - the "echo" of the Big Bang. The effect is usually utilized to study large galaxy clusters.
"What we're doing is asking a different question than what has been previously asked. We're using a technique that's been around for some time and that researchers have been very successful with, and we're using it to answer a totally different question in a totally different subfield of astronomy," Megan Gralla, postdoctoral fellow at John Hopkins, said.
Gas falling toward the center of a galaxy normally cools, as most of the material starts to collapse into new stars, while the rest falls into the black hole. In older galaxies, this gas does not cool enough to collapse into young stars. Older galaxies are usually elliptical in shape, providing this class of galaxies with its name.
Astronomers are still uncertain why some galactic black holes produce particles which emit radio waves and heat gas, preventing star formation.
"I was stunned when I saw this paper, because I've never thought that detecting the SZ effect from active galactic nuclei was possible. I was wrong. ... It makes those of us who work on the SZ effect from galaxy clusters feel old; research on the SZ effect has entered a new era," Eiichiro Komatsu from the Max Planck Institute, an astronomer who studies the phenomenon, told the press.
Study of ancient galaxies and how their central black holes could hinder the development of new stars was profiled in the journal Monthly Notices of the Royal Astronomical Society.
