Constraints on the positron emission from pulsar populations with AMS-02 data

TL;DR

This paper uses high-precision AMS-02 positron data to constrain the properties and distribution of Galactic pulsars, shedding light on their role in the observed positron excess in cosmic rays.

Contribution

It introduces a comprehensive simulation framework for Galactic pulsar populations to interpret AMS-02 positron data and determine pulsar characteristics influencing the positron flux.

Findings

Constraints on pulsar properties from AMS-02 data

Impact of different pulsar distribution and evolution assumptions

Identification of pulsar parameters dominating positron flux

Abstract

Electron and positron fluxes in cosmic rays are currently measured with unprecedented precision by AMS-02 up to TeV energies, and represent unique probes for the local properties of our Galaxy. The interpretation of their spectra is at present still debated, especially for the excess of positrons above 10 GeV. The hypothesis that pulsars can significantly contribute to this excess has been consolidated after the observation of gamma-ray halos at TeV energies of a few degree size around Geminga and Monogem pulsars. However, the spatial and energetic Galactic distribution of pulsars and the details of the positron production, acceleration and release from these sources are not yet fully understood. I will describe how we can use the high-precision AMS-02 positron data to constrain the main properties of the Galactic pulsar population and of the positron acceleration needed to explain the observed fluxes. This is achieved by simulating a large number of Galactic pulsar populations, following the most recent self-consistent modelings for the pulsar spin-down and evolution properties, calibrated on catalog observations. By fitting the positron AMS-02 data together with a secondary component due to collisions of primary cosmic rays with the interstellar medium, we determine the physical parameters of the pulsars dominating the positron flux, and assess the impact of different assumptions on radial distributions, spin-down properties, Galactic propagation scenarios and positron emission time.