Cosmic-Ray Propagation and Interactions in the Galaxy

Strong, A. W.; Moskalenko, I. V.; Птускин, В. С.

doi:10.1146/annurev.nucl.57.090506.123011

Cited by 1,171 publications

(1,390 citation statements)

References 151 publications

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“…The prevailing theory describing CR propagation throughout the galaxy is based on the diffusion model, for which a detailed description can be found in [51][52][53]. The diffusive paradigm follows naturally from the expectation that charged CR species follow tangled paths as they scatter resonantly off of the turbulent features in the galactic magnetic field whose size match their gyroradii; this explains the observed isotropy of CRs and the retention of CR species in the galaxy.…”

Section: Consistent Modeling Of the High-energy Skymentioning

confidence: 99%

Cosmic ray anomalies from the MSSM?

Cotta

Conley

Gainer

et al. 2011

J. High Energ. Phys.

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Abstract:The recent positron excess in cosmic rays (CR) observed by the PAMELA satellite may be a signal for dark matter (DM) annihilation. When these measurements are combined with those from FERMI on the total (e + + e − ) flux and from PAMELA itself on thep/p ratio, these and other results are difficult to reconcile with traditional models of DM, including the conventional mSUGRA version of Supersymmetry even if boosts as large as 10 3−4 are allowed. In this paper, we combine the results of a previously obtained scan over a more general 19-parameter subspace of the MSSM with a corresponding scan over astrophysical parameters that describe the propagation of CR. We then ascertain whether or not a good fit to this CR data can be obtained with relatively small boost factors while simultaneously satisfying the additional constraints arising from gamma ray data. We find that a specific subclass of MSSM models where the LSP is mostly pure bino and annihilates almost exclusively into τ pairs comes very close to satisfying these requirements. The lightestτ in this set of models is found to be relatively close in mass to the LSP and is in some cases the nLSP. These models lead to a significant improvement in the overall fit to the data by an amount ∆χ 2 ∼ 1/dof in comparison to the best fit without Supersymmetry while employing boosts ∼ 100. The implications of these models for future experiments are discussed.

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Section: Consistent Modeling Of the High-energy Skymentioning

confidence: 99%

Cosmic ray anomalies from the MSSM?

Cotta

Conley

Gainer

et al. 2011

J. High Energ. Phys.

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“…The first thing to note is that in collision physics, T nuc , the kinetic energy per nucleon is the quantity of interest. At the same values of T nuc we see that the accelerated particle distributions-the cosmic rays-have abundances of H, He, CNO and Fe in the ratio of 1:0.07:0.0044:0.0003 [18,19]. From Mori [32], drawing on the work of J.-P. Meyer [33], we take the composition of the target ISM material with relative abundances of H:He:CNO:NeMgSiS:Fe in the ratio 1:0.096:1.38e-3:2.11e-4:3.25e-5.…”

Section: Metallicity Correctionsmentioning

confidence: 81%

“…Besides diffusive escape from the target-rich Galactic disk, convective Galactic winds from the superpositions of the hot gases of O/B stars and supernovae will cause a systematic expulsion of cosmic rays to the halo of the Galaxy. MHD turbulence in the Galactic magnetic field could cause systematic acceleration of cosmic rays during transport [19]. Although breaks may be expected, demonstrating such a break in the cosmic-ray proton spectrum has proven to be difficult, for reasons of (1) limitations on our knowledge of the secondary pion distributions in p-p collisions, and (2) metallicity corrections on secondary pion production [18,20].…”

Section: The Cosmic-ray Spectrum In the Local Interstellar Mediummentioning

confidence: 99%

“…The secondary to primary ratios of cosmic-ray nuclei can also be modeled by an average escape grammage (R) through which cosmic-ray particles with rigidity R pass [19]. Analysis of cosmic-ray ion composition often uses the empirical function (R) = β 0 (R/R 0 ) −a for R > R 0 and (R) = β 0 0 for R < R 0 , where…”

Section: The Cosmic-ray Spectrum In the Local Interstellar Mediummentioning

confidence: 99%

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Impact of Fermi-LAT and AMS-02 results on cosmic-ray astrophysics

Dermer

2015

EPJ Web of Conferences

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Abstract. This article reviews a few topics relevant to Galactic cosmic-ray astrophysics, focusing on the recent AMS-02 data release and Fermi Large Area Telescope data on the diffuse Galactic γ -ray emissivity. Calculations are made of the diffuse cosmic-ray induced p + p → π 0 → 2γ spectra, normalized to the AMS-02 cosmic-ray proton spectrum at ≈ 10 − 100 GV, with and without a hardening in the cosmic-ray proton spectrum at rigidities R 300 GV. A single power-law momentum "shock" spectrum for the local interstellar medium cosmic-ray proton spectrum cannot be ruled out from the γ -ray emissivity data alone without considering the additional contribution of electron bremsstrahlung. Metallicity corrections are discussed, and a maximal range of nuclear enhancement factors from 1.52 to 1.92 is estimated. Origins of the 300 GV cosmic-ray proton and α-particle hardening are discussed.

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“…In this experiment, we have simulated a 720 × 360 × 128 cube using the Galprop code Strong et al (2007) that has a model of the diffuse gamma-ray emission of the Milky Way. The units of the pixels are photons cm − 2s −1 sr −1 M eV −1 .…”

Section: Diffuse Emission Of the Galaxymentioning

confidence: 99%

Fermi Gamma-ray Space Telescope

Harding¹,

Omodei²

AccessScience

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The multiscale variance stabilization Transform (MSVST) has recently been proposed for Poisson data denoising (Zhang et al. 2008a). This procedure, which is nonparametric, is based on thresholding wavelet coefficients. The restoration algorithm applied after thresholding provides good conservation of source flux. We present in this paper an extension of the MSVST to 3D data-in fact 2D-1D data-when the third dimension is not a spatial dimension, but the wavelength, the energy, or the time. We show that the MSVST can be used for detecting and characterizing astrophysical sources of high-energy gamma rays, using realistic simulated observations with the Large Area Telescope (LAT). The LAT was launched in June 2008 on the Fermi Gammaray Space Telescope mission. Source detection in the LAT data is complicated by the low fluxes of point sources relative to the diffuse celestial foreground, the limited angular resolution, and the tremendous variation in that resolution with energy (from tens of degrees at ∼30 MeV to ∼0.1 • at 10 GeV). The high-energy gamma-ray sky is also quite dynamic, with a large population of sources such active galaxies with accretion-powered black holes producing high-energy jets, episodically flaring. The fluxes of these sources can change by an order of magnitude or more on time scales of hours. Perhaps the majority of blazars will have average fluxes that are too low to be detected but could be found during the hours or days that they are flaring. The MSVST algorithm is very fast relative to traditional likelihood model fitting, and permits efficient detection across the time dimension and immediate estimation of spectral properties. Astrophysical sources of gamma rays, especially active galaxies, are typically quite variable, and our current work may lead to a reliable method to quickly characterize the flaring properties of newly-detected sources.

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Cosmic-Ray Propagation and Interactions in the Galaxy

Cited by 1,171 publications

References 151 publications

Cosmic ray anomalies from the MSSM?

Cosmic ray anomalies from the MSSM?

Impact of Fermi-LAT and AMS-02 results on cosmic-ray astrophysics

Fermi Gamma-ray Space Telescope

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