NASA's Chandra Observatory Finds Cosmic Showers Halt Galaxy Growth

This galaxy cluster comes from a sample of over 200 that were studied to determine how giant black holes at their centers affect the growth and evolution of their host galaxy, as reported in our latest press release. This study revealed that an unusual form of cosmic precipitation enables a feedback loop of cooling and heating, stifling star formation in the middle of these galaxy clusters.

Abell 2597, shown here, is a galaxy cluster located about one billion light years from Earth. This image contains X-rays from NASA's Chandra X-ray Observatory (blue), optical data from the Hubble Space Telescope and the Digitized Sky Survey (yellow) and emission from hydrogen atoms (red) from the Walter Baade Telescope in Chile.

According to this new study, the regulation of the largest black hole and their host galaxies works as follows: in some galaxies, such as NGC 2597, hot gas is able to quickly cool through radiation and energy loss, in a process called precipitation. The clouds of cool gas that result then fall into the central supermassive black hole, producing jets that heat the gas and prevent further cooling.

The researchers used Chandra data to estimate how long it should take for the gas to cool at different distances from the black holes in the study. Using that information, they were able to accurately predict the "weather" around each of the black holes.

They found that the precipitation feedback loop driven by energy produced by the black hole jets prevents the showers of cold clouds from getting too strong. The Chandra data indicate that the regulation of this precipitation has been going on for the last 7 billion years or more.

More information at http://chandra.harvard.edu/photo/2015/a2597/index.html

-Megan Watzke, CXC