Starburst galaxy sheds light on longstanding cosmic mysteryNovember 03, 2009An international collaboration that includes scientists 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. "Although cosmic rays were first detected 100 years ago, their origins have been a mystery," says Holder. "One idea has been that they are produced by supernova explosions, but there was never any direct proof until now. This gamma ray measurement by VERITAS looks at a galaxy different from our own where there are 30 times as many supernovae. The fact that we see gamma rays indicates that there are many more cosmic rays being produced by these supernovae." In the active starburst region at the Cigar Galaxy's center, stars are being formed at a rate approximately ten times more rapidly than in "normal" galaxies like our Milky Way, Holder says. The cosmic rays produced in the formation, life, and death of the massive stars in this region eventually produce diffuse gamma-ray emission via their interactions with interstellar gas and radiation. Holder and former postdoctoral researcher Ester Aliu and doctoral student Dana Boltuch were involved in the study from UD. Holder scheduled all of the observations as chair of the team's observing time allocation committee, and he and Aliu ran the array of telescopes based in southern Arizona to collect a significant portion of the 137 hours of data collected for the study. Holder provided a critical secondary analysis with an independent analysis package to confirm the result. The Bartol Research Institute is a research center in UD's Department of Physics and Astronomy. The institute's primary function is to carry out forefront scientific research with a primary focus on physics, astronomy, and space sciences. University of Delaware |
|||||||||||||||||||||
| Related Cosmic Rays Current Events and Cosmic Rays News Articles New panchromatic capabilities of Hubble reveal an unprecedented view of the universe Shown in an extremely broad range of color and showcasing more than twelve billion years of cosmic history, Hubble's recent image is a full-glory cosmic renaissance of the history of the Universe. NASA unveils latest results from lunar mission, helps prepare for next stage of scientific discovery NASA's current mission in orbit around the moon, the Lunar Reconnaissance Orbiter, or LRO, has been providing crucial insights about our nearest celestial neighbor since its launch in June. Cosmic rays hunted down A thin rain of charged particles continually bombards our atmosphere from outer space. The mysterious particles were first detected 100 years ago but until 10 years ago when a new type of telescope began to come online physicists weren't sure where the "cosmic rays" came from or how they were generated. Lightning-produced radiation a potential health concern for air travelers New information about lightning-emitted X-rays, gamma rays and high-energy electrons during thunderstorms is prompting scientists to raise concerns about the potential for airline passengers and crews to be exposed to harmful levels of radiation. VERITAS telescopes help solve 100-year-old mystery: The origin of cosmic rays Nearly 100 years ago, scientists detected the first signs of cosmic rays - subatomic particles (mostly protons) that zip through space at nearly the speed of light. Iowa State researchers contribute to discovery of gamma rays from starburst galaxy Iowa State University astrophysicists contributed to the recent discovery that a galaxy quickly creating new stars is also a source of high energy gamma rays. NASA's Fermi Telescope Detects Gamma-Ray From Nearby galaxies undergoing a furious pace of star formation also emit lots of gamma rays, say astronomers using NASA's Fermi Gamma-ray Space Telescope. Princeton paleomagnetists put controversy to rest Princeton University scientists have shown that, in ancient times, the Earth's magnetic field was structured like the two-pole model of today, suggesting that the methods geoscientists use to reconstruct the geography of early land masses on the globe are accurate. Cosmic Rays Hit Space Age High Planning a trip to Mars? Take plenty of shielding. According to sensors on NASA's ACE (Advanced Composition Explorer) spacecraft, galactic cosmic rays have just hit a Space Age high. North meets south? Glaciers move together in far-flung regions Results of a new study add evidence that climate swings in the northern hemisphere over the past 12,000 years have been tightly linked to changes in the tropics. More Cosmic Rays Current Events and Cosmic Rays News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||