Observing Signals of Spectral Features in the Cosmic-Ray Positrons and Electrons from Milky Way Pulsars
Update: 2022-11-30
Description
Observing Signals of Spectral Features in the Cosmic-Ray Positrons and Electrons from Milky Way Pulsars by Ilias Cholis et al. on Wednesday 30 November
The Alpha Magnetic Spectrometer (AMS-02) has provided unprecedented precision
measurements of the electron and positron cosmic-ray fluxes and the positron
fraction spectrum. At the higher energies, sources as energetic local pulsars,
may contribute to both cosmic-ray species. The discreteness of the source
population, can result in features both on the positron fraction measurement
and in the respective electron and positron spectra. For the latter, those
would coincide in energy and would contrast predictions of smooth spectra as
from particle dark matter. In this work, using a library of pulsar population
models for the local part of the Milky Way, we perform a power-spectrum
analysis on the cosmic-ray positron fraction. We also develop a technique to
cross-correlate the electron and positron fluxes. We show that both such
analyses, can be used to search statistically for the presence of spectral
wiggles in the cosmic-ray data. For a significant fraction of our pulsar
simulations, those techniques are already sensitive enough to give a signal for
the presence of those features above the regular noise, with forthcoming
observations making them even more sensitive. Finally, by cross-correlating the
AMS-02 electron and positron spectra, we find an intriguing first hint for a
positive correlation between them, of the kind expected by a population of
local pulsars.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15709v1
The Alpha Magnetic Spectrometer (AMS-02) has provided unprecedented precision
measurements of the electron and positron cosmic-ray fluxes and the positron
fraction spectrum. At the higher energies, sources as energetic local pulsars,
may contribute to both cosmic-ray species. The discreteness of the source
population, can result in features both on the positron fraction measurement
and in the respective electron and positron spectra. For the latter, those
would coincide in energy and would contrast predictions of smooth spectra as
from particle dark matter. In this work, using a library of pulsar population
models for the local part of the Milky Way, we perform a power-spectrum
analysis on the cosmic-ray positron fraction. We also develop a technique to
cross-correlate the electron and positron fluxes. We show that both such
analyses, can be used to search statistically for the presence of spectral
wiggles in the cosmic-ray data. For a significant fraction of our pulsar
simulations, those techniques are already sensitive enough to give a signal for
the presence of those features above the regular noise, with forthcoming
observations making them even more sensitive. Finally, by cross-correlating the
AMS-02 electron and positron spectra, we find an intriguing first hint for a
positive correlation between them, of the kind expected by a population of
local pulsars.
arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.15709v1
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