In a joint effort a team of international scientists from nearly 90 research institutions has studied the sources of the highest energy particles in the universe, ultrahigh-energy cosmic rays. According to the new findings the cosmic rays are likely generated from supermassive black holes in the hearts of nearby active galaxies

Discovered nearly 100 years ago, cosmic rays are subatomic particles, including nuclei of atoms such as hydrogen, oxygen, carbon, nitrogen or iron and the sun an the stars emit lower-energy cosmic rays. However up until now the source of ultrahigh-energy cosmic rays, which are 100 million times more energetic than anything produced by the most powerful particle smashers on Earth, has been unexplained.

During the last hundred years scientists have proposed various theories to identify the sources of the cosmic rays.

In 2004 the Auger Observatory began collecting data about the origin of cosmic rays in 2004. The observatory includes a 1,200-square-mile grid of 1,600 large, instrumented water tanks and four sites with a total of 24 telescopes that detect faint fluorescent flashes in the sky caused when a cosmic ray particle triggers an air shower.

After three years, the Pierre Auger Collaboration has finished a study which was published in the Friday, November 9 issue of the journal Science.

The study reports that since 2004 the observatory has recorded 80 cosmic rays with ultrahigh-energies above 40 billion billion electron volts. Of the 28 most energetic events – those with energies above 57 billion billion electron volts – 20 come from the direction of the known locations of some of the 318 Active Galactic Nuclei with the Auger Observatory’s field of view.

Six of the remaining eight cosmic rays come from directions where the source may be obscured by other matter in our galaxy.

Active Galactic Nuclei are thought to be powered by supermassive black holes that are devouring large amounts of matter. They have long been considered sites where high-energy particle production might take place.

While most galaxies have black holes at their center, only a fraction of all galaxies have an AGN. The exact mechanism of how AGNs can accelerate particles to energies 100 million times higher than the most powerful particle accelerator on Earth is still a mystery

“We have taken a big step forward in solving the mystery of the nature and origin of the highest-energy cosmic rays,” said Nobel Prize winner and University of Chicago professor emeritus James Cronin, who founded the Pierre Auger Observatory with Alan Watson of the University of Leeds. “The age of cosmic-ray astronomy has arrived. In the next few years, our data will permit us to identify the exact sources of these cosmic rays and how they accelerate these particles.”