Speaker
Description
The AMS-02 spaceborne particle spectrometer has measured the cosmic-ray flux of positrons with high precision, reaching up to hundreds of GeV. This has provided invaluable insights into the local sources of antimatter in cosmic rays. The hypothesis that pulsars and their nebulae are responsible for the cosmic ray positron flux has recently gained further support from observations of gamma-ray emissions at GeV and TeV energies around several nearby sources, indicating that these sources indeed accelerate electron-positron pairs to high energies.
In this analysis, we examine the Galactic pulsar population that is relevant to explaining the observed cosmic ray positron flux. We compute the positron emission from pulsars in the ATNF catalog by employing state-of-the-art models and exploring different assumptions about the injection spectrum, spin-down, and particle transport models. The particle emission properties that cannot be directly measured for each pulsar are modeled using advanced phenomenological approaches, which incorporate current theoretical knowledge and are constrained by multi-wavelength observations of pulsars and their surrounding nebulae and halos. By fitting the contributions of these pulsars to the AMS-02 data, we find that a few nearby, middle-aged catalog pulsars can significantly dominate the positron flux, especially those located within 1 kpc of Earth. We present a shortlist of the 10 most important sources identified across the various tested models. We recommend that these sources undergo multi-wavelength follow-up observations to determine their injection spectrum properties through analyses in X-ray and gamma rays, spanning from GeV to TeV energies. These results provide a foundation for future observational campaigns that will enhance our understanding of cosmic ray positron transport and pulsar emission processes.
