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Related papers: Fermi Pulsars and the Cosmic Ray Knee

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We calculate the low-momentum N-N effective potential obtained in the OBE approximation, inside a nuclear plasma at finite temperature, as described by the relativistic $ \sigma $-$ \omega $ model. We analyze the screening effects on the…

Nuclear Theory · Physics 2019-08-15 J. Diaz Alonso , E. Gallego , A. Perez

Many of the blazars observed by Fermi actually have the peak of their time-averaged gamma-ray emission outside the $\sim$ GeV Fermi energy range, at $\sim$ MeV energies. The detailed shape of the emission spectrum around the $\sim$ MeV peak…

High Energy Astrophysical Phenomena · Physics 2025-02-05 F. Tavecchio , L. Nava , A. Sciaccaluga , P. Coppi

Energetic particles, traditionally called Cosmic Rays, were discovered nearly a hundred years ago, and their origin is still uncertain. Their main constituents are the normal nuclei as in the standard cosmic abundances of matter, with some…

Astrophysics · Physics 2007-05-23 Peter Biermann , Guenter Sigl

Stochastic acceleration of cosmic rays in second order Fermi processes is usually considered too slow to reach ultra-high energies, except in specific cases. In this paper we present the energy spectrum obtained from second order Fermi…

High Energy Astrophysical Phenomena · Physics 2018-05-23 Tobias Winchen , Stijn Buitink

The DArk Matter Particle Explorer (DAMPE), a space-based high precision cosmic ray detector, has just reported the new measurement of the total electron plus positron energy spectrum up to 4.6 TeV. A notable feature in the spectrum is the…

High Energy Astrophysical Phenomena · Physics 2018-02-28 Kun Fang , Xiao-Jun Bi , Peng-Fei Yin

Using a laser plasma accelerator, experiments with a 80 TW and 30 fs laser pulse demonstrated quasi-monoenergetic electron spectra with maximum energy over 0.4 GeV. This is achieved using a supersonic He gas jet and a sharp density ramp…

Plasma Physics · Physics 2012-10-03 S. Fourmaux , K. Ta Phuoc , P. Lassonde , S. Corde , G. Lebrun , V. Malka , A. Rousse , J. C. Kieffer

The knee phenomenon of the cosmic ray spectrum, which plays an important role in studying the acceleration mechanism of cosmic rays, is still an unsolved mystery. We try to reconcile the knee spectra measured by ARGO-YBJ and Tibet-III. A…

High Energy Astrophysical Phenomena · Physics 2015-10-22 Yi Zhao , Huan-Yu Jia , Feng-Rong Zhu

The detection of gravitational waves and electromagnetic counterparts from a binary neutron star (BNS) merger confirmed that it is accompanied by the launch of fast merger ejecta. Analogous to supernova remnants, forward shocks formed by…

High Energy Astrophysical Phenomena · Physics 2018-10-12 Shigeo S. Kimura , Kohta Murase , Peter Mészáros

Nuclear caloric curves have been analyzed using an expanding Fermi gas hypothesis to extract average nuclear densities. In this approach the observed flattening of the caloric curves reflects progressively increasing expansion with…

Nuclear Experiment · Physics 2009-11-07 J. B. Natowitz , K. Hagel , Y. Ma , M. Murray , L. Qin , S. Shlomo , R. Wada , J. Wang

We discuss the possibility that a dominant fraction of the cosmic rays above the ankle is due to a single nearby source, considering in particular the radio galaxy Centaurus A. We focus on the properties of the source spectrum and…

High Energy Astrophysical Phenomena · Physics 2024-11-28 Silvia Mollerach , Esteban Roulet

The chart of nuclei could be enlarged with a branch describing neutron stars that are huge nuclei of a few solar masses held together by gravity force and sustained by the pressure due to the degenerate Fermi sea. We contend in this…

High Energy Physics - Phenomenology · Physics 2026-04-07 Domenec Espriu

The nature of the knee in the all-particle spectrum of cosmic rays remains subject of much investigation, especially in the aftermath of recent measurements claiming the detection of a knee-like feature in the spectrum of the light…

High Energy Astrophysical Phenomena · Physics 2019-06-13 Carlo Mascaretti , Pasquale Blasi , Carmelo Evoli

Our numerical simulations show that the reconnection of magnetic field becomes fast in the presence of weak turbulence in the way consistent with the Lazarian and Vishniac (1999) model of fast reconnection. We trace particles within our…

Astrophysics of Galaxies · Physics 2015-05-18 A. Lazarian , G. Kowal , E. Vishniac , E. de Gouveia dal Pino

The semiclassical method for description of the radiative strength function is used for asymmetric nuclei with $N \ne Z$. The theory is based on the linearized Vlasov-Landau equations in two-component finite Fermi liquid. The dependence of…

Nuclear Theory · Physics 2017-08-23 V. A. Plujko , M. O. Kavatsyuk , O. O. Kavatsyuk

Recent measurements of gamma rays from the powerful quasar 3C273 by the Compton Gamma Ray Observatory show that a powerful cosmic accelerator must be operating. In this paper the evidence for proton acceleration is collected with the result…

Astrophysics · Physics 2009-10-22 Karl Mannheim

An ultra-short (about 30 fs) petawatt laser pulse focused with a wide focal spot (about 100 microns) in a rarefied plasma (electron density of order 10^{17} per cm^3) excites a nonlinear plasma wakefield which can accelerate injected…

Plasma Physics · Physics 2009-11-10 L. M. Gorbunov , S. Yu. Kalmykov , P. Mora

The theory of first order Fermi acceleration at shocks assumes that particles diffuse due to scattering off slow-moving magnetic irregularities. However, cosmic rays are closely tied to magnetic field lines, and the transport process,…

Astrophysics · Physics 2011-05-23 P. Duffy , J. G. Kirk , Y. A. Gallant , R. O. Dendy

Theory of the first-order Fermi acceleration of cosmic ray particles at relativistic shock waves is reviewed. We consider shocks with parallel and oblique, sub- and super-luminal magnetic field configurations and with finite-amplitude…

Astrophysics · Physics 2007-05-23 M. Ostrowski

Theoretical studies of cosmic ray particle acceleration in the first-order Fermi process at relativistic shocks are reviewed. At the beginning we discuss the acceleration processes acting at mildly relativistic shock waves. An essential…

Astrophysics · Physics 2007-05-23 Michal Ostrowski

Active Galactic Nuclei (AGNs) and their relativistic jets belong to the most promising class of ultra-high-energy cosmic ray (UHECR) accelerators. This compact review summarises basic experimental findings by recent instruments, and…

High Energy Astrophysical Phenomena · Physics 2022-11-23 Frank M. Rieger