Ultrahigh energy cosmic ray deflection by the intergalactic magnetic field

ABSTRACT The ARCADE 2 balloon bolometer along with a number of other instruments have detected what appears to be a radio synchrotron background at frequencies below about 3 GHz. Neither extragalactic radio sources nor diffuse Galactic emission can currently account for this finding. We use the locally measured cosmic ray electron population, demodulated for effects of the Solar wind, and other observational constraints combined with a turbulent magnetic field model to predict the radio synchrotron emission for the Local Bubble. We find that the spectral index of the modelled radio emission is roughly consistent with the radio background. Our model can approximately reproduce the observed antenna temperatures for a mean magnetic field strength B between 3 and 5 nT. We argue that this would not violate observational constraints from pulsar measurements. However, the curvature in the predicted spectrum would mean that other, so far unknown sources would have to contribute below 100 MHz. Also, the magnetic energy density would then dominate over thermal and cosmic ray electron energy density, likely causing an inverse magnetic cascade with large variations of the radio emission in different sky directions as well as high polarization. We argue that this disagrees with several observations and thus that the magnetic field is probably much lower, quite possibly limited by equipartition with the energy density in relativistic or thermal particles (B = 0.2−0.6 nT). In the latter case, we predict a contribution of the Local Bubble to the unexplained radio background at most at the per cent level.

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Measurements of the time-dependent cosmic-ray Sun shadow with seven years of IceCube data: Comparison with the Solar cycle and magnetic field models

Physical Review D ◽

10.1103/physrevd.103.042005 ◽

2021 ◽

Vol 103 (4) ◽

Author(s):

M. G. Aartsen ◽

R. Abbasi ◽

M. Ackermann ◽

J. Adams ◽

J. A. Aguilar ◽

...

Keyword(s):

Magnetic Field ◽

Solar Cycle ◽

Cosmic Ray ◽

Time Dependent ◽

Data Comparison

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The Origin and Dynamical Effects of the Magnetic Fields and Cosmic Rays in the Disk of the Galaxy

Symposium - International Astronomical Union ◽

10.1017/s0074180900004873 ◽

1970 ◽

Vol 39 ◽

pp. 168-183

Author(s):

E. N. Parker

Keyword(s):

Magnetic Field ◽

Cosmic Rays ◽

Magnetic Fields ◽

Dynamical Behavior ◽

Cosmic Ray ◽

Interested Reader ◽

Written Text ◽

The Galaxy ◽

Basic Ideas ◽

The Magnetic Field

The topic of this presentation is the origin and dynamical behavior of the magnetic field and cosmic-ray gas in the disk of the Galaxy. In the space available I can do no more than mention the ideas that have been developed, with but little explanation and discussion. To make up for this inadequacy I have tried to give a complete list of references in the written text, so that the interested reader can pursue the points in depth (in particular see the review articles Parker, 1968a, 1969a, 1970). My purpose here is twofold, to outline for you the calculations and ideas that have developed thus far, and to indicate the uncertainties that remain. The basic ideas are sound, I think, but, when we come to the details, there are so many theoretical alternatives that need yet to be explored and so much that is not yet made clear by observations.

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