FIAN expert proposed a new hypothesis for the origin of cosmic rays


Side view of a galaxy having a symmetrical pair of jets emanating from the center, where is the black hole.

In the Physics Institute. PN Lebedev Physical Institute (LPI) proposed a new explanation for the origin of cosmic rays. Opened last year, the U.S. Fermi gamma-ray observatory giant bubbles, symmetrically placed above and below the galactic plane in the central part may be a relic of the active phase of the galactic center, which is a massive black hole. Millions of years ago the jet (jets of material) pumped up the energy of these areas. He also filled the disk of the galaxy high-energy particles — cosmic rays.

In 1912, we opened the cosmic rays. Experiments balloon showed that the degree of ionization of the air increases with altitude, i.e. ionization is on. So were open fast particles coming from space.

Cosmic rays — * a stream of charged particles, mostly — protons at very high energies as high as 10 ^ 19-10 ^ 20 electron volts. In contrast to the neutral particles, they are deflected in a magnetic field, so to determine their source path can not be.

Where did the cosmic rays? Where does such a tremendous energy? After all, the energy density of cosmic rays is the same as the density of the interstellar gas.
On the role of their origin — Energy — in our galaxy is quite suitable supernova explosions.

For 40 years, the prevailing theory in astrophysics of cosmic ray acceleration by shock waves from supernova explosions. It is based on the so-called Fermi acceleration. In the 40-ies of the Fermi conjectured that in our galaxy there are molecular clouds of ionized gas with a frozen-in magnetic field are. Charged particles passing through the clouds, clouds are deflected by magnetic fields and make the chaotic motion in the interstellar medium. This process is similar to the motion of light particles in a gas of very heavy particles. As a result, the energy of charged particles increases many times, they are accelerated. This is called the Fermi acceleration.

Streams of charged particles interact with the random magnetic fields in the Milky Way — this is today's model describing cosmic rays. The average density of magnetic field energy density of the energy of the gas in interstellar space density of cosmic rays and — one order, they actually are. This suggests that cosmic rays are closely related to magnetic fields. The magnetic field arises in the ionized gas, and its density can not be greater than the energy density of the gas. In the 70s there was a universal theory of cosmic ray acceleration by shock waves of very large amplitude propagating at high speed in the turbulent interstellar medium.

Shock waves produce supernova explosions. This theory, however, does not explain the observed acceleration exhaustively for which should be processed in cosmic rays to 15% of the kinetic energy of the shock wave.

LPI employee, doctor of physical and mathematical sciences Jacob Istomin proposed his hypothesis of the origin of cosmic rays:

"In the center of our galaxy is a black hole whose mass is 4 • 10 ^ 6 solar masses. Now its activity (radiated power) is low. But in the past it could be many orders of magnitude greater — as in active galactic nuclei. And it is in the active phase of the galactic nucleus could emit jets — collimated jets of matter moving along the axis of rotation of the black hole.
The galaxy is a giant wheel. The galactic center — it's a black hole.
In the past, the U.S. Gamma-Ray Observatory has detected near the center of the so-called Fermi bubbles, symmetrically located relative to the plane of the galaxy. Their sizes — eight kpc in height (above and below the galactic plane) for six kpc width — quite comparable with the galactic (the radius of the Galaxy — fifteen kpc). Symmetrical bubbles in terms reminiscent of butterfly wings. There is a range of high-energy radiation. The only explanation for this phenomenon — the whole area of bubbles filled with particles of very high energy. Energy there as much as in the cosmic rays in the galaxy.


Fig. 1. Fermi Bubbles "eyes" of the cosmic gamma-ray telescope "Fermi".

The study of particle acceleration in the jets of active galactic nuclei showed that the energy of the particles can reach 10 ^ 20 electron volts. It is likely — the experimental data and calculations confirm this — Fermi bubbles are the remains of two-sided jet, which consisted of high-energy particles. Now they are also filled the disk and halo of our Galaxy. Based on the diffusion of the particles in space, were estimated time of occurrence of the jet — about 24 million years ago — and the time of his "work" — at least 10 million years old. The particles have not lost their energy and, when confronted with the cold protons give gamma radiation. Now there is no jet, but its remnants are observed. Quite possibly, it was he pumped with energy and filled with cosmic rays and bubbles galactic disk. "

Source: ANI LPI-Inform

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