Assistant Professor Jamie Holder and collaborators first to discover very-high-energy gamma rays in the Cigar Galaxy
November 2, 2009 - An international collaboration that includes Assistant Professor Jamie Holder from the University of Delaware's Bartol Research Institute in the Department of Physics and Astronomy has discovered very-high-energy gamma rays in the Cigar Galaxy (M82), a bright galaxy filled with exploding stars 12 million light years from Earth.
The gamma rays observed by the team have energies more than a trillion times higher than the energy of visible light and are the highest-energy photons ever detected from a galaxy undergoing large amounts of star formation.
The discovery, made from data taken over a two-year-long observing campaign by the VERITAS collaboration of more than 100 scientists from 22 different institutions in the United States, Ireland, United Kingdom, and Canada, appears in the Nov. 1 advance online edition of the scientific journal Nature.
VERITAS (Very Energetic Radiation Imaging Telescope Array System) is a gamma ray observatory located at the Fred Lawrence Whipple Observatory near Amado, Ariz.
The finding provides “strong evidence” that exploding stars are the origin of cosmic rays, according to Jamie Holder, assistant professor of physics and astronomy at the University of Delaware and deputy spokesperson for the VERITAS collaboration.
Produced in violent processes in our own galaxy and beyond, cosmic rays are actually energetic particles that continually bombard Earth's atmosphere. They are important, Holder says, because they make up a large fraction of the energy budget of our galaxy, The Milky Way. The amount of energy in cosmic rays is comparable to the energy contained in both starlight, and in Galactic magnetic fields, Holder notes.