The statistics of black holes and their masses strongly suggests that their mass distribution has a cutoff towards lower masses near \(3 \times 10^{6}\) M\(_{\odot}\). This is consistent with a ...classical formation mechanism from the agglomeration of the first massive stars in the universe. However, when the masses of the stars approach \(10^{6}\) M\(_{\odot}\), the stars become unstable and collapse, possibly forming the first generation of cosmological black holes. Here we speculate that the claimed detection of an isotropic radio background may constitute evidence of the formation of these first supermassive black holes, since their data are compatible in spectrum and intensity with synchrotron emission from the remnants. The model proposed fulfills all observational conditions for the background, in terms of single-source strength, number of sources, far-infrared and gamma-ray emission. The observed high energy neutrino flux is consistent with our calculations in flux and spectrum. The proposal described in this paper may also explain the early formation and growth of massive bulge-less disk galaxies as derived from the massive, gaseous shell formed during the explosion prior to the formation of a supermassive black hole.
In the Heliosphere, power-law particle distributions are observed e.g. upstream of interplanetary shocks, which can result from superdiffusive transport. This non-Gaussian transport regime may result ...from intermittent magnetic field structures. Recently, we showed that a Lévy flight model reproduces the observed features at shocks: power-law distributions upstream and enhanced intensities at the shock. We extend the Lévy flight model to study the impact of superdiffusive transport on particle acceleration at shocks. The acceleration time scale and spectral slope are compared to Gaussian diffusion and a Lévy walk model. The fractional transport equation is solved by sampling the number density with the corresponding stochastic differential equation that is driven by an alpha-stable Lévy distribution. For both Gaussian and superdiffusive transport we use a modified version of CRPropa 3.2. We obtain the number density and energy spectra for constant and energy-dependent anomalous diffusion and find, compared to the case of Gaussian diffusion, harder energy spectra at the shock as well as faster acceleration. The spectral slope is even harder than predicted for Lévy walks. Lévy flight models of superdiffusive transport lead to observed features in the Heliosphere. We further show that superdiffusive transport impacts the acceleration process by changing the probability to escape the shock. The flexibility of the Lévy flight model allows for further studies in the future, taking the shock geometry and magnetic field structure into account.
We study the possibility that the gamma ray emission in the Fermi bubbles
observed is produced by cosmic ray electrons with a spectrum similar to
Galactic cosmic rays. We argue that the cosmic ray ...electrons steepen near 1 TeV
from $E^{-3}$ to about $E^{-4.2}$, and are partially secondaries derived from
the knee-feature of normal cosmic rays. We speculate that the observed feature
at $\sim 130$ GeV could essentially be due to inverse Compton emission off a
pair-production peak on top of a turn-off in the $\gamma$ ray spectrum at $\sim
130$ GeV. It suggests that the knee of normal cosmic rays is the same
everywhere in the Galaxy. A consequence could be that all supernovae
contributing give the same cosmic ray spectrum, with the knee feature given by
common stellar properties; in fact, this is consistent with the supernova
theory proposed by Bisnovatyi-Kogan (1970), a magneto-rotational mechanism, if
massive stars converge to common properties in terms of rotation and magnetic
fields just before they explode.
We study the possibility that the gamma ray emission in the Fermi bubbles observed is produced by cosmic ray electrons with a spectrum similar to Galactic cosmic rays. We argue that the cosmic ray ...electrons steepen near 1 TeV from \(E^{-3}\) to about \(E^{-4.2}\), and are partially secondaries derived from the knee-feature of normal cosmic rays. We speculate that the observed feature at \(\sim 130\) GeV could essentially be due to inverse Compton emission off a pair-production peak on top of a turn-off in the \(\gamma\) ray spectrum at \(\sim 130\) GeV. It suggests that the knee of normal cosmic rays is the same everywhere in the Galaxy. A consequence could be that all supernovae contributing give the same cosmic ray spectrum, with the knee feature given by common stellar properties; in fact, this is consistent with the supernova theory proposed by Bisnovatyi-Kogan (1970), a magneto-rotational mechanism, if massive stars converge to common properties in terms of rotation and magnetic fields just before they explode.
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