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Open AccessJournal ArticleDOI

Cosmic-Ray Positron Energy Spectrum Measured by PAMELA

TLDR
The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy.
Abstract
Precision measurements of the positron component in the cosmic radiation provide important information about the propagation of cosmic rays and the nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA has been used to make a new measurement of the cosmic-ray positron flux and fraction that extends previously published measurements up to 300 GeV in kinetic energy. The combined measurements of the cosmic-ray positron energy spectrum and fraction provide a unique tool to constrain interpretation models. During the recent solar minimum activity period from July 2006 to December 2009, approximately 24 500 positrons were observed. The results cannot be easily reconciled with purely secondary production, and additional sources of either astrophysical or exotic origin may be required.

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Spectrum of Electrons Accelerated in Supernova Remnants.

TL;DR: This model of cosmic ray electrons accelerated by supernova remnants (SNRs) finds that electrons exhibit substantially steeper spectra than protons, and the difference between the electron and proton spectral index (power law slope) ranges from 0.1 to 0.4.
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Cosmic-ray propagation with DRAGON2: II. Nuclear interactions with the interstellar gas

TL;DR: In this paper, the authors provide a detailed description of the nuclear cross sections and decay network as implemented in the forthcoming release of the galactic propagation code DRAGON2, and apply the different prescriptions to compute quantities of interest to interpret local CR fluxes (e.g., nuclear fragmentation timescales, secondary and tertiary source terms).
Journal ArticleDOI

Asymmetric dark matter in braneworld cosmology

TL;DR: In this paper, the authors investigate the effect of a braneworld expansion era on the relic density of asymmetric dark matter and find that the enhanced expansion rate in the early universe predicted by the RSII model leads to earlier particle freeze-out and an enhanced relic density.
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Sensitivity of primordial black hole abundance on the reheating phase

TL;DR: In this paper, the authors investigate the sensitivity of the reheating history to the abundance of primordial black holes (PBHs) in a single-field inflation model with a quasi-inflection point, and find that both the peak position and amplitude of the extended mass fraction of PBHs in DM can vary by many orders of magnitude.
Journal ArticleDOI

Dark Stars: A Review

TL;DR: The evolution of dark stars from their inception at as they accrete mass from their surroundings to become supermassive stars, some even reaching masses and luminosities, making them detectable with the upcoming James Webb Space Telescope.
References
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