X-ray stripes show source for cosmic rays
Astronomers may have found the first direct evidence for where high-energy cosmic rays detected here on Earth come from, thanks to NASA’s Chandra X-ray observatory
Astronomers may have found the first direct evidence for where high-energy cosmic rays detected here on Earth come from, thanks to NASA’s Chandra X-ray observatory.
Observing the remains of Tycho’s Supernova (pictured above), scientists observed stripes in the X-ray emissions from it – the first time these emissions had been picked up.
This may provide evidence for a theory of how magnetic fields can amplify charged particles to the colossal energies found in cosmic rays.
In the theory, charged particles – protons and electrons – bounce back and forth across the shockwave of a supernova and the tangled magnetic field lines it produces, gaining energy with each crossing.
As the electrons spiral between the magnetic field lines they emit X-rays, which the Chandra satellite can observe.
Although the regions of differing magnetic field strength have been previously predicted by theory, the neatness of the X-ray stripes in the observations of Tycho’s Supernova has been a surprise to scientists, who were expecting the blast region to be chaotic.
Using the spacing between the stripes to calculate the energy of the protons, they were calculated to have energies 100 times greater than the maximum that can be produced at the Large Hadron Collider – energies that equal the highest energy cosmic rays that have been detected coming from within our Galaxy.
Because cosmic rays are made up of charged particles, they are deflected by other magnetic fields as they travel through space, making it difficult to find their source.
But these observations of the supernova, named after the 16th-century Danish astronomer Tycho Brahe, lend strong support to the cataclysmic demise of stars being likely sources for some of the cosmic rays measured here on Earth.