Fermi Reveals a Cosmic-Ray Cocoon in Cygnus

Credit: NASA/DOE/Fermi LAT Collaboration/I. A. Grenier and L. Tibaldo

The constellation Cygnus, now visible in the western sky as twilight deepens after sunset, hosts one of our galaxy’s richest-known stellar construction zones. Astronomers viewing the region at visible wavelengths see only hints of this spectacular activity thanks to a veil of nearby dust clouds forming the Great Rift, a dark lane that splits the Milky Way, a faint band of light marking our galaxy’s central plane.

Located in the vicinity of the second-magnitude star Gamma Cygni, the star-forming region was named Cygnus X when it was discovered as a diffuse radio source by surveys in the 1950s. Now, a study using data from NASA’s Fermi Gamma-ray Space Telescope finds that the tumult of star birth and death in Cygnus X has managed to corral fast-moving particles called cosmic rays.

Cosmic rays are subatomic particles — mainly protons — that move through space at nearly the speed of light. In their journey across the galaxy, the particles are deflected by magnetic fields, which scramble their paths and make it impossible to backtrack the particles to their sources.

Full Story: http://www.nasa.gov/mission_pages/GLAST/news/cygnus-cocoon.html