Cosmic Rays from Galactic Centers

Where do cosmic rays [ http://en.wikipedia.org/wiki/Cosmic_rays ] come from? A major step toward answering this century old question [ http://en.wikipedia.org/wiki/Cosmic_rays#History ] may have just come in from the Auger Observatory [ http://www.auger.org/observatory/ ] project, the world's premier cosmic ray observatory. That high energy fundamental particles are barreling through the universe has been known [ http://www.p-ng.si/public/pao/history.php ] for about a century. Because ultra high energy cosmic rays [ http://en.wikipedia.org/wiki/Cosmic_rays#Ultra-high-energy_cosmic_rays ] are so rare and because their extrapolated directions are so imprecise, no progenitor objects have ever been unambiguously implied [ http://www.auger.org/technical_info/icrc_2007.html ]. New results [ http://www.auger.org/news/PRagn/AGN_correlation.html ] from Auger, however, indicate that 12 of 15 ultra high energy cosmic rays have sky directions statistically consistent with the positions of nearby active galactic nuclei [ http://en.wikipedia.org/wiki/Active_galactic_nucleus ]. These galactic centers [ http://antwrp.gsfc.nasa.gov/apod/ap991017.html ] are already known to emit great amounts of light and are likely powered by large black holes [ http://cosmology.berkeley.edu/Education/BHfaq.html ]. The Auger results [ http://www.auger.org/news/PRagn/AGN_correlation_more.html ] also indicate [ http://www.sciencemag.org/cgi/content/abstract/sci;318/5852/938 ] that the highest energy cosmic rays [ http://en.wikipedia.org/wiki/GZK_cutoff ] are protons, since the electric charge of higher energy nuclei would force the Milky Way Galaxy [ http://antwrp.gsfc.nasa.gov/apod/ap050825.html ]'s magnetic field [ http://hypertextbook.com/facts/2001/RebeccaRudberg.shtml ] to deflect and effectively erase progenitor source direction. Pictured above, an artist illustrates a cosmic ray [ http://antwrp.gsfc.nasa.gov/apod/ap060814.html ] striking the Earth's atmosphere and creating a shower of secondary particles detectable on the surface. The image of Centaurus A [ http://antwrp.gsfc.nasa.gov/apod/ap030806.html ] digitally superposed near the top signifies one such active galaxy from which cosmic rays [ http://www.mininggazette.com/stories/articles.asp?articleID=9354 ] might originate.

Pierre Auger Observatory Team [ http://www.auger.org/collaboration/ ],

Goddard Space Flight Center (GSFC)

Centaurus

http://antwrp.gsfc.nasa.gov/apod/ap071112.html

SPD-APOD-ap071112