A recent study revealed that the massive black holes emitting radio-frequency-particles at near-light speed can block the formation of new stars in mature galaxies.
The study revealed that the jets of ‘radio-frequency-feedback’ flowing from mature galaxies’ central black hole eventually thwart hot free gas from cooling and collapsing into baby stars.
Tobias Marriage, assistant professor of physics and astronomy at Johns Hopkins and co-lead author of the study stated that, “As you look back into the past history of the universe, you see these galaxies forming stars. At some point, they stop forming stars and the question is: Why? Basically, these active black holes give a reason for why stars stop forming in the universe.”
The study has been published in the Monthly Notices of the Royal Astronomical Society journal.
A well-known research technique is being used by the scientists in order to make these discoveries possible. Sunyaev–Zel’dovich effect signature found by Johns Hopkins postdoctoral fellow Megan Gralla, which is typically used to study large galaxy clusters and can also be used for learning a great deal about smaller star formations. Sunyaev–Zel’dovich effect happens when high-energy electrons in hot gas interact with faint light in the cosmic microwave background, light left over from the earliest times when the universe was a thousand times hotter and a billion times denser than today.
Gralla said, “Sunyaev–Zel’dovich effect is typically used to study clusters of hundreds of galaxies, though the galaxies we are looking for are much smaller and have just a companion or two. Actually, we are asking a different question than what has been formerly asked. We are 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.”
Eiichiro Komatsu, director of the Max Planck Institute for Astrophysics in Germany and an expert in the field who was not involved in the research stated that, “I was shocked when I saw this research, because I have never assumed that detecting the SZ effect from active galactic nuclei was possible. I was actually 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.”
When we look into the space, the hot gas haggard into a galaxy can cool and condense to make stars. Some gas also flows into the black hole of the galaxy that grows collectively with the stellar population. The cycles repeat at regular intervals, more hot gas is pulled into the galaxy that cool and condense, more stars begin to shine and the central black hole gets bigger.
Marriage, Gralla, along with their fellow colleagues found that the elliptical galaxies with radio-frequency feedback—relativistic radio-frequency-emitting particles shelling from the massive central black holes at their center at close to the speed of light—all contain hot gas and a scarcity of baby stars. This seems to be a strong evidence for their hypothesis that this radio-frequency feedback is the “off switch” for star formation in mature galaxies.
Marriage further stated that, “It’s not yet clear why black holes in mature elliptical galaxies begin to emit radio-frequency feedback. The exact mechanism behind this is not fully understood and there are still debates.”
Furthermore, this study poses new challenges to the theory of galaxy formation, as there were hardly any data which told us how much hot gas there is around galaxies,” Komatsu said.
Marriage and Gralla were joined as co-lead authors by Devin Crichton, a Johns Hopkins graduate student in physics and astronomy, and Wenli Mo, a physics and astronomy undergraduate student who earned her degree in May 2011. She is now studying at the University of Florida on a National Science Foundation Graduate Fellowship.
The team of researchers used data from the Atacama Cosmology Telescope, a 6-meter telescope in northern Chile; the National Radio Astronomy Observatory’s Very Large Array in New Mexico and its Green Bank Telescope in West Virginia; the Parkes Observatory in Australia; and the European Space Agency’s Herschel Space Observatory.