New constraints on modelling the random magnetic field of the MW

Beck, Marcus C.; Beck, Alexander M.; Beck, Rainer; Dolag, K.; Strong, A. W.; Nielaba, Peter

doi:10.1088/1475-7516/2016/05/056

Cited by 77 publications

(62 citation statements)

References 127 publications

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“…They argued that, while the obliteration of high-order moments by the magnetic field of the Milky Way might be ruled out, additional isotropisation can be due to large-scale magnetised winds around galaxies, acceleration of CRs outside of galaxies, or to an increased acceleration activity by the distant (and hence more isotropic) distribution of galaxies. However, the regular component of the galactic magnetic field is yet not known well enough to make very accurate predictions (e. g. Jansson & Farrar 2012b,a;Beck et al 2014, and references therein).…”

Section: Angular Power Spectrummentioning

confidence: 99%

Propagation of ultrahigh energy cosmic rays in extragalactic magnetic fields: a view from cosmological simulations

Hackstein¹,

Vazza²,

Brüggen³

et al. 2016

Mon. Not. R. Astron. Soc.

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We use the CRPropa code to simulate the propagation of ultra high energy cosmic rays (with energy 10 18 eV and pure proton composition) through extragalactic magnetic fields that have been simulated with the cosmological ENZO code. We test both primordial and astrophysical magnetogenesis scenarios in order to investigate the impact of different magnetic field strengths in clusters, filaments and voids on the deflection of cosmic rays propagating across cosmological distances. We also study the effect of different source distributions of cosmic rays around simulated Milky-Way like observers. Our analysis shows that the arrival spectra and anisotropy of events are rather insensitive to the distribution of extragalactic magnetic fields, while they are more affected by the clustering of sources within a ∼ 50 Mpc distance to observers. Finally, we find that in order to reproduce the observed degree of isotropy of cosmic rays at ∼ EeV energies, the average magnetic fields in cosmic voids must be ∼ 0.1 nG, providing limits on the strength of primordial seed fields.

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Section: Angular Power Spectrummentioning

confidence: 99%

Propagation of ultrahigh energy cosmic rays in extragalactic magnetic fields: a view from cosmological simulations

Hackstein¹,

Vazza²,

Brüggen³

et al. 2016

Mon. Not. R. Astron. Soc.

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“…2.1 succintly review the features of the two largescale GMF models en vogue in 2014, which first appeared in [1] (PTKN11) and in [2] (JF12), and, in sec. 2.2, the small-scale latest model of [3]; to close sec. 2 I will then review a little trick which allows one to obtain cosmic rays deflection variances without even knowing what the (random) GMF model is, first discussed in [4].…”

Section: Introductionmentioning

confidence: 94%

“…Reviewing all of them is a daunting task, so I will very partially choose to describe in some detail only the two latest largescale models of [1] and [2], and mention this year's small-scale effort appeared in [3]; for many more details, a beautiful and very recent review on the GMF is [7].…”

Section: Models Of the Galactic Magnetic Fieldmentioning

confidence: 99%

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The Galactic Magnetic Field and Ultra-High Energy Cosmic Rays

Urban¹

2016

Proceedings of International Symposium for Ultra-High Energy Cosmic Rays (UHECR2014)

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The Galactic Magnetic Field is a peeving and importune screen between Ultra-High Energy Cosmic Rays and us cosmologists, engaged in the combat to unveil their properties and origin, as it deviates their paths towards the Earth in unpredictable ways. I will, in this order: briefly review the available field models on the market; explain a little trick which allows one to obtain cosmic rays deflection variances without even knowing what the (random) GMF model is; and argue that there is a lack of anisotropy in the large scales cosmic rays signal, which the Galactic field can do nothing about.

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“…When particles escape from the acceleration region, they start diffusing around the SNR mainly along the direction of the large scale magnetic field B 0 = B 0 z. Inside the Galactic disc the magnetic field has a typical coherence scale L c ≈ 100 pc [5], hence in a region of size L c around the SNR (located at z = 0) we can approximate the transport of particle to occur inside a cylindric flux tube. This 1D geometry breaks down for distances larger than L c , when magnetic field lines tangle, losing their coherent structure.…”

Section: Cr Propagation In the Vicinity Of The Sourcementioning

confidence: 99%

Contribution to diffuse gamma-ray emission coming from self-confined CRs around their Galactic sources

Morlino¹,

D'Angelo²,

Blasi³

et al. 2017

Proceedings of 35th International Cosmic Ray Conference — PoS(ICRC2017)

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Recent observations of the diffuse Galactic γ-ray emission by the Fermi-LAT satellite have shown significant deviations from models which assume the same diffusion properties for cosmic rays (CR) throughout the Galaxy. We explore the possibility that a fraction of this diffuse Galactic emission could be due to hadronic interactions of CRs self-confined in the region around their sources. In fact, freshly accelerated CRs that diffuse away from the acceleration region can trigger the streaming instability able to amplify magnetic disturbance and to reduce the particle diffusion. When this happen, CRs are trapped in the near source region for a time longer than expected and an extended γ-ray halo is produces around each source. Here we calculate the contribution to the diffuse γ-ray background due to the overlap along lines of sight of several of these extended halos. We find that if the density of neutrals is low, the halos can account for a substantial fraction of the diffuse emission observed by Fermi-LAT, depending on the orientation of the line of sight with respect to the direction of the galactic center.

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New constraints on modelling the random magnetic field of the MW

Cited by 77 publications

References 127 publications

Propagation of ultrahigh energy cosmic rays in extragalactic magnetic fields: a view from cosmological simulations

Propagation of ultrahigh energy cosmic rays in extragalactic magnetic fields: a view from cosmological simulations

The Galactic Magnetic Field and Ultra-High Energy Cosmic Rays

Contribution to diffuse gamma-ray emission coming from self-confined CRs around their Galactic sources

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