Further analysis yielded the result the two researchers were seeking: Somewhere in the vastness of space, the millions or billions of light-years between the black hole jets and Fermi's instruments, something was indeed scattering the photons—and very, very subtly. Calculations by the researchers, published online 17 September in The Astrophysical Journal Letters, suggest that a magnetic field equivalent to about one-quadrillionth the strength of Earth's magnetism had interacted with the photons. This phenomenon had distorted their energies just enough to create a "halo" effect in the gamma ray images of the supermassive black holes.
Friday, September 24, 2010
Primordial Magnetic Field May Permeate the Universe - ScienceNOW: If it exists, such a magnetic field could scatter high-energy photons emitted from the jets of a supermassive black hole and blur images collected by detectors aboard the Fermi spacecraft just as a mist can blur an image on a photograph on Earth. The effect is so minuscule, however, that it can't be seen with current technology on a single image of jets from a supermassive black hole. So Ando and Kusenko took Fermi data from 170 different black holes and combined them into a single, composite image. Then they compared the composite with the product of a mathematical model, showing what the image should have looked like if all of the high-energy photons from the supermassive black holes had hit Fermi's detectors at the expected energy levels. But the real and simulated images didn't match (insets).