Isaac Scientific Publishing

Advances in Astrophysics

Extragalactic and Galactic Cosmic Rays

Download PDF (693.6 KB) PP. 173 - 186 Pub. Date: November 1, 2016

DOI: 10.22606/adap.2016.13004

Author(s)

  • Ya. N. Istomin*
    P.N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 119991, Russia 2Moscow Institute Physics and Technology, Institutskii per. 9, Dolgoprudnyi, Moscow region, 141700, Russia

Abstract

From the analysis of the flux of high energy particles, E > 3·1018eV , it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, q ¯(E) ∝ E−2.7, with the same index of 2.7 that has the distribution of Galactic cosmic rays before so called knee, E < 3 · 1015eV . However, for the average power of extragalactic sources, which is of E ' 1043erg s−1, at least two orders exceeds the power emitted by the Galaxy in cosmic rays, assuming that the density of galaxies is estimated as Ng ' 1Mpc−3. Considering that such power can be provided by relativistic jets from active galactic nuclei with the power E ' 1045 − 1046erg s−1, we estimate the density of extragalactic sources of cosmic rays as Ng ' 10−2 − 10−3 Mpc−3. Assuming the same nature of Galactic and extragalactic rays, we conclude that the Galactic rays were produced by a relativistic jet emitted from the Galactic center during the period of its activity in the past. The remnants of a bipolar jet are now observed in the form of bubbles of relativistic gas above and below the Galactic plane. The break, observed in the spectrum of Galactic rays (knee), is explained by fast escape of energetic particles, E > 3 · 1015eV , from the Galaxy because of the dependence of the coefficient of diffusion of cosmic rays on energy, D ∝ E0.7. The obtained index of the density distribution of particles over energy, N(E) ∝ E−2.7−0.7/2 = E−3.05, for E > 3 · 1015eV agrees well with the observed one, N(E) ∝ E−3.1. Estimated time of termination of the jet in the Galaxy is 4.2 · 104 years ago.

Keywords

Cosmic ray theory; ultra high energy cosmic rays

References

[1] Abbasi, R.U., et al., Study of Small-Scale Anisotropy of Ultra-High-Energy Cosmic Rays Observed in Stereo by the High Resolution Fly’s Eye Detector, 2004. ApJ, 610, L73.

[2] Aloisio, R., Berezinsky V., Grigorieva, S., Analytic calculations of the spectra of ultra high energy cosmic ray nuclei. II. The general case of background radiation, 2013, Astropart. Phys., 41, 94.

[3] Bell, A.R., The acceleration of cosmic rays in shock fronts. I, (II), 1978, MNRAS, 182, 147, (443).

[4] Berezinsky, V., Gazizov, A., Grigorieva S., On astrophysical solution to ultrahigh energy cosmic rays, 2006, Phys. Rev. D, 74, 043005.

[5] Berezinsky, V., UHECR: Signatures and models, 2013, EPJ Web of Conference, 53, 01003.

[6] Berezinsky, V., Extragalactic cosmic rays and their signatures, 2014, Astropart. Phys., 53, 120.

[7] Blasi, P., Amato, E., Diffusive propagation of cosmic rays from supernova remnants in the Galaxy. II: anisotropy2012, JCaP , Issue 1, id. 011.

[8] Blasi, P., The origin of galactic cosmic rays, 2013, The Astronomy and Astropart. Review, 21, 70.

[9] Greisen, K., End to the Cosmic-Ray Spectrum?, 1966, Phys. Rev. Lett., 16, 748.

[10] HESS Collaboration, Acceleration of petaelectronvolt protons in the Galactic Centre, 2016, Nature, 531, Issue 7595, 476.

[11] Istomin, Ya.N., On the origin of galactic cosmic rays, 2014, New Astronomy, 27, 13.

[12] Krymskii, G.F., A regular mechanism for the acceleration of charged particles on the front of a shock wave, 1977, Soviet Physics-Doklady, 22, 327.

[13] Mao-Li, M., Xin-Wu, C., Dong-Rong, J., Min-Feng, G., Estimation of jet’s power, Chin. J. Astron. Astrophys., 2008, 8, 39.

[14] Pierre Auger Collaboration, Correlation of the Highest-Energy Cosmic Rays with Nearby Extragalactic Objects, 2007, Science, 318, 938.

[15] Pierre Auger Collaboration, Correlation of the highest-energy cosmic rays with the positions of nearby active galactic nuclei, 2008, Astropart. Phys., 29, 188.

[16] Pierre Auger Collaboration, Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter, 2010, Astropart. Phys., 34, 314.

[17] Ptuskin, V.S., On the origin of galactic cosmic rays, 2007, Phys. Uspechi, 50, 534.

[18] Stanev, T., Engle, R., Mucke A., Protheroe, R.J., Rachen, J.P., Propagation of ultrahigh energy protons in the nearby universe, 2000, Phys. Rev. D, 62, 093005.

[19] Su, M., Slatyer, T.R., Finkbeiner, D.P., Giant Gamma-ray Bubbles from Fermi-LAT: Active Galactic Nucleus Activity or Bipolar Galactic Wind?, 2010, ApJ, 724, 1044.

[20] Takami, H., Sato, K., Implications to sources of ultra-high-energy cosmic rays from their arrival distribution, 2009, Astropart. Phys., 30, 306.

[21] Taylor, A.M., Ahlers, M., Aharonian F.A., Need for a local source of ultrahigh-energy cosmic-ray nuclei2011, Phys. Rev. D, 84, 10500, ArXiv:astro-ph/1107.2055.

[22] Tinyakov, P. for the Telescope Array Collaboration, Cosmic rays from the ankle to the cutoff, 2014, Nuclear Instruments and Methods in Physics Reseach A, 742, 29.

[23] Zatsepin, G.T., Kuz’min, V.A., Upper Limit of the Spectrum of Cosmic Rays, 1966, JETP Letters, 4, 78.