scholarly journals Sound-wave instabilities in dilute plasmas with cosmic rays: implications for cosmic ray confinement and the Perseus X-ray ripples

2020 ◽  
Vol 493 (4) ◽  
pp. 5323-5335 ◽  
Author(s):  
Philipp Kempski ◽  
Eliot Quataert ◽  
Jonathan Squire
Keyword(s):  
Cosmic Rays ◽  
Thermal Plasma ◽  
Acoustic Waves ◽  
Cosmic Ray ◽  
High Energy ◽  
Density Fluctuations ◽  
Sound Waves ◽  
X Ray ◽  
Acoustic Instability ◽  
Anisotropic Viscosity

ABSTRACT Weakly collisional, magnetized plasmas characterized by anisotropic viscosity and conduction are ubiquitous in galaxies, haloes, and the intracluster medium (ICM). Cosmic rays (CRs) play an important role in these environments as well, by providing additional pressure and heating to the thermal plasma. We carry out a linear stability analysis of weakly collisional plasmas with CRs using Braginskii MHD for the thermal gas. We assume that the CRs stream at the Alfvén speed, which in a weakly collisional plasma depends on the pressure anisotropy (Δp) of the thermal plasma. We find that this Δp dependence introduces a phase shift between the CR-pressure and gas-density fluctuations. This drives a fast-growing acoustic instability: CRs offset the damping of acoustic waves by anisotropic viscosity and give rise to wave growth when the ratio of CR pressure to gas pressure is ≳αβ−1/2, where β is the ratio of thermal to magnetic pressure, and α, typically ≲1, depends on other dimensionless parameters. In high-β environments like the ICM, this condition is satisfied for small CR pressures. We speculate that the instability studied here may contribute to the scattering of high-energy CRs and to the excitation of sound waves in galaxy-halo, group and cluster plasmas, including the long-wavelength X-ray fluctuations in Chandra observations of the Perseus cluster. It may also be important in the vicinity of shocks in dilute plasmas (e.g. cluster virial shocks or galactic wind termination shocks), where the CR pressure is locally enhanced.

scholarly journals What can we learn about Cosmic Rays from the UV, Optical, Radio and X-Ray Observations of Supernova 1979c in M 100?

1981 ◽  
Vol 94 ◽  
pp. 51-52
Author(s):  
G.G.C. Palumbo ◽  
G. Cavallo
Keyword(s):  
Cosmic Rays ◽  
Direct Evidence ◽  
Cosmic Ray ◽  
High Energy ◽  
Nearby Galaxy ◽  
Optical Information ◽  
X Ray ◽  
Free Parameters ◽  
High Energy Particles ◽  
Early Phases

Theories on the Origin of Cosmic Rays almost invariably invoke the Supernova (SN) phenomenon in its early phases as the cause for production and acceleration of high energy particles. So far only optical information about SNe has been available and from it there is no direct evidence of Cosmic Rays. It is not surprising then that models of Cosmic Ray production are still rich in free parameters. On April 19th 1979 a very bright (~12 mag) SN, labelled 1979c, was detected in the relatively nearby galaxy (~16 Mpc) M 100 (≡NGC 4321). This galaxy, incidentally has produced 4 SNe in 78 years. Event 1979c was followed quite intensively in the optical and UV (with IUE) regions of the spectrum as well as observed at radio and X-ray frequencies. A detailed account of these observations is in press (Panagia et al. 1980). Here we summarize only very briefly the results relevant to the present discussion.

New fermionic dark matters, extended Standard Model and cosmic rays

2017 ◽  
Vol 32 (26) ◽  
pp. 1730023 ◽  
Author(s):  
Jae-Kwang Hwang
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Elementary Particles ◽  
X Ray ◽  
High Energy Cosmic Rays ◽  
Dark Matters ◽  
X Ray Background ◽  
New Particles

Three generations of leptons and quarks correspond to the lepton charges (LCs) in this work. Then, the leptons have the electric charges (ECs) and LCs. The quarks have the ECs, LCs and color charges (CCs). Three heavy leptons and three heavy quarks are introduced to make the missing third flavor of EC. Then the three new particles which have the ECs are proposed as the bastons (dark matters) with the rest masses of 26.121 eV/c2, 42.7 GeV/c2 and 1.9 × 10[Formula: see text] eV/c2. These new particles are applied to explain the origins of the astrophysical observations like the ultra-high energy cosmic rays and supernova 1987A anti-neutrino data. It is concluded that the 3.5 keV X-ray peak observed from the cosmic X-ray background spectra is originated not from the pair annihilations of the dark matters but from the X-ray emission of the Q1 baryon atoms which are similar in the atomic structure to the hydrogen atom. The presence of the 3.5 keV cosmic X-ray supports the presence of the Q1 quark with the EC of −4/3. New particles can be indirectly seen from the astrophysical observations like the cosmic ray and cosmic gamma ray. In this work, the systematic quantized charges of EC, LC and CC for the elementary particles are used to consistently explain the decay and reaction schemes of the elementary particles. Also, the strong, weak and dark matter forces are consistently explained.

scholarly journals Constraining the cosmic ray spectrum in the vicinity of the supernova remnant W28: from sub-GeV to multi-TeV energies

2020 ◽  
Vol 635 ◽  
pp. A40
Author(s):  
V. H. M. Phan ◽  
S. Gabici ◽  
G. Morlino ◽  
R. Terrier ◽  
J. Vink ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Ionization Rate ◽  
High Energy ◽  
Radio Waves ◽  
X Ray

Context. Supernova remnants interacting with molecular clouds are ideal laboratories to study the acceleration of particles at shock waves and their transport and interactions in the surrounding interstellar medium. Aims. Here, we focus on the supernova remnant W28, which over the years has been observed in all energy domains from radio waves to very-high-energy gamma rays. The bright gamma-ray emission detected from molecular clouds located in its vicinity revealed the presence of accelerated GeV and TeV particles in the region. An enhanced ionization rate has also been measured by means of millimeter observations, but such observations alone cannot tell us whether the enhancement is due to low-energy (MeV) cosmic rays (either protons or electrons) or the X-ray photons emitted by the shocked gas. The goal of this study is to determine the origin of the enhanced ionization rate and to infer from multiwavelength observations the spectrum of cosmic rays accelerated at the supernova remnant shock in an unprecedented range spanning from MeV to multi-TeV particle energies. Methods. We developed a model to describe the transport of X-ray photons into the molecular cloud, and we fitted the radio, millimeter, and gamma-ray data to derive the spectrum of the radiating particles. Results. The contribution from X-ray photons to the enhanced ionization rate is negligible, and therefore the ionization must be due to cosmic rays. Even though we cannot exclude a contribution to the ionization rate coming from cosmic-ray electrons, we show that a scenario where cosmic-ray protons explain both the gamma-ray flux and the enhanced ionization rate provides the most natural fit to multiwavelength data. This strongly suggests that the intensity of CR protons is enhanced in the region for particle energies in a very broad range covering almost six orders of magnitude: from ≲100 MeV up to several tens of TeV.

scholarly journals High energy cosmic ray interactions and UHECR composition problem

2019 ◽  
Vol 210 ◽  
pp. 02001
Author(s):  
Sergey Ostapchenko
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Hadronic Interactions ◽  
High Energy Cosmic Rays ◽  
Cosmic Ray Interactions ◽  
Composition Problem

The differences between contemporary Monte Carlo generators of high energy hadronic interactions are discussed and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs) is studied. Key directions for further model improvements are outlined. The prospect for a coherent interpretation of the data in terms of the UHECR composition is investigated.

scholarly journals Cosmic Rays and the Dynamic Balance in the Large Magellanic Cloud

1990 ◽  
Vol 123 ◽  
pp. 537-541
Author(s):  
Carl E. Fichtel ◽  
Mehmet E. Ozel ◽  
Robert G. Stone
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Dynamic Balance ◽  
Cosmic Ray ◽  
Large Magellanic Cloud ◽  
High Energy ◽  
Magellanic Cloud ◽  
Density Level ◽  
Energy Gamma ◽  
Galactic Dynamic

AbstractPresent and future measurement of the Large Magellanic Cloud (LMC) particularly in the radio and high energy gamma ray range offer the possibility of understanding the density and distribution of the cosmic rays in a galaxy other than our own and the role that they play in galactic dynamic balance. After a study of the consistency of the measurements and interpretation of the synchrotron radiation from our own galaxy, the cosmic ray distribution for the LMC is calculated under the assumption that the cosmic ray nucleon to electron ratio is the same and the relation to the magnetic fields are the same, although the implications of alternatives are discussed. It is seen that the cosmic ray density level appears to be similar to that in our own galaxy, but varying in position in a manner generally consistent with the concept of correlation with the matter on a broad scale.

scholarly journals X-Ray Evidence for the Acceleration, Containment, and Emission of High Energy Flare Particles

1974 ◽  
Vol 57 ◽  
pp. 421-422 ◽  
Author(s):  
Kenneth J. Frost
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Solar Observatory ◽  
Time Structure ◽  
Radio Bursts ◽  
X Rays ◽  
Thermal Component ◽  
X Ray ◽  
Type Iii ◽  
Explosive Phase

An instrument aboard the Fifth Orbiting Solar Observatory has observed hard solar X-rays from January 1969 to May 1972. A large number of X-ray bursts generated by solar cosmic ray flares have been observed. The X-ray bursts consist, in general, of two non-thermal components. The earliest occurring non-thermal component, coincident with the explosive phase, consists of a group of one to about ten X-ray bursts that are, for each burst, approximately 10 s duration and symmetrical in rise and decay. The time structure and multiplicity of these bursts is remarkably similar to that found in type III radio bursts in the meterwave band. The spectra of these bursts steepens sharply at energies greater than 100 keV indicating a limit at this energy for electron acceleration during the explosive or flash phase of the flare. For several flares these multiple X-ray bursts have occurred in coincidence with a group of type III bursts.

scholarly journals On the flux of high-energy cosmogenic neutrinos and the influence of the extragalactic magnetic field

2019 ◽  
Vol 488 (1) ◽  
pp. L119-L122 ◽  
Author(s):  
David Wittkowski ◽  
Karl-Heinz Kampert
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Large Scale ◽  
Neutrino Flux ◽  
Cosmic Ray ◽  
High Energy ◽  
Observation Time ◽  
Cosmological Time ◽  
Cosmic Background ◽  
The Universe

ABSTRACT Cosmogenic neutrinos originate from interactions of cosmic rays propagating through the universe with cosmic background photons. Since both high-energy cosmic rays and cosmic background photons exist, the existence of high-energy cosmogenic neutrinos is certain. However, their flux has not been measured so far. Therefore, we calculated the flux of high-energy cosmogenic neutrinos arriving at the Earth on the basis of elaborate 4D simulations that take into account three spatial degrees of freedom and the cosmological time-evolution of the universe. Our predictions for this neutrino flux are consistent with the recent upper limits obtained from large-scale cosmic-ray experiments. We also show that the extragalactic magnetic field has a strong influence on the neutrino flux. The results of this work are important for the design of future neutrino observatories, since they allow to assess the detector volume and observation time that are necessary to detect high-energy cosmogenic neutrinos in the near future. An observation of such neutrinos would push multimessenger astronomy to hitherto unachieved energy scales.

USING THE WESTERBORK RADIO OBSERVATORY TO DETECT UHE COSMIC PARTICLES INTERACTING ON THE MOON

2006 ◽  
Vol 21 (supp01) ◽  
pp. 147-152
Author(s):  
J. BACELAR ◽  
O. SCHOLTEN ◽  
A. G. de BRUYN ◽  
H. FALCKE
Keyword(s):  
Cosmic Rays ◽  
Radio Telescope ◽  
Radio Pulse ◽  
Lunar Regolith ◽  
Neutrino Flux ◽  
Cosmic Ray ◽  
High Energy ◽  
Observation Time ◽  
Flux Limit ◽  
Null Result

Ultra-High-Energy (UHE) particles of cosmological origin (cosmic-rays and neutrinos), carry information on the most spectacular events known. These extremely energetic (energies larger than 1 ZeV= 1021 eV) cosmic-rays or neutrinos initiate in the lunar regolith a cascade of charged particles which acts as a radio pulse emitter. The instantaneous power produced can be detected here at the Earth, with a radio telescope operating at the optimal frequency window around 150 MHz. Using 12 telescopes of the Westerbork Synthesis Radio Telescope, WSRT, with a field of view covering the whole lunar surface, our calculations show that one should identify 10 UHE events within an observation time of 500 hours, assuming an extrapolated power law dependence of the highest ever measured cosmic-ray events, around an energy of 1020 eV. A null result will determine unambiguously the GKZ effect for the cosmic-ray flux and improve the present world upper limit on the neutrino flux above 1 ZeV, by three orders of magnitude, allowing for the first time to test the Waxman-Bahcall neutrino flux limit.

scholarly journals Composition and Galactic Confinement of Cosmic Rays

1971 ◽  
Vol 2 ◽  
pp. 740-756
Author(s):  
Maurice M. Shapiro
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Interstellar Space ◽  
Heavy Nuclei ◽  
High Energy Astrophysics ◽  
Transit Times ◽  
The Galaxy ◽  
Path Lengths

The ‘Galactic’ cosmic rays impinging on the Earth come from afar over tortuous paths, traveling for millions of years. These particles are the only known samples of matter that reach us from regions of space beyond the solar system. Their chemical and isotopic composition and their energy spectra provide clues to the nature of cosmic-ray sources, the properties of interstellar space, and the dynamics of the Galaxy. Various processes in high-energy astrophysics could be illuminated by a more complete understanding of the arriving cosmic rays, including the electrons and gamma rays.En route, some of theprimordialcosmic-ray nuclei have been transformed by collision with interstellar matter, and the composition is substantially modified by these collisions. A dramatic consequence of the transformations is the presence in the arriving ‘beam’ of considerable fluxes of purely secondary elements (Li, Be, B), i.e., species that are, in all probability, essentially absent at the sources. We shall here discuss mainly the composition of the arriving ‘heavy’ nuclei -those heavier than helium - and what they teach us about thesourcecomposition, the galactic confinement of the particles, their path lengths, and their transit times.

scholarly journals Diffuse cosmic X-rays from non-thermal intergalactic bremsstrahlung

1970 ◽  
Vol 37 ◽  
pp. 392-401
Author(s):  
Joseph Silk
Keyword(s):  
Cosmic Rays ◽  
Intergalactic Medium ◽  
Energy Requirement ◽  
Cosmic Ray ◽  
X Rays ◽  
Degree Of Ionization ◽  
X Ray ◽  
Normal Galaxies ◽  
X Ray Background ◽  
High Degree

The diffuse X-ray background between 1 keV and 1 MeV is interpreted as non-thermal bremsstrahlung in the intergalactic medium. The observed break in the X-ray spectrum at ∼40 keV yields the heat input to the intergalactic medium, the break being produced by ionization losses of sub-cosmic rays. Proton bremsstrahlung is found not to yield as satisfactory an agreement with observations as electron bremsstrahlung: excessive heating tends to occur. Two alternative models of cosmic ray injection are discussed, one involving continuous injection by evolving sources out to a redshift of about 3, and the other model involving injection by a burst of cosmic rays at a redshift of order 10. The energy density of intergalactic electrons required to produce the observed X-rays is ∼ 10−4 eV/cm3. Assuming a high density (∼ 10−5 cm−3) intergalactic medium, the energy requirement for cosmic ray injection by normal galaxies is ∼ 1058–59ergs/galaxy in sub-cosmic rays. The temperature evolution of the intergalactic medium is discussed, and we find that a similar energy input is also required to explain the observed high degree of ionization (if 3C9 is at a cosmological distance).

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