Probing the astrophysical origin of high-energy cosmic-ray electrons with Monte Carlo simulation

Abstract

Abstract. High-energy cosmic-ray electrons reveal some remarkable spectral features, the most noteworthy of which is the rise in the positron fraction above 10 GeV. Due to strong energy loss during propagation, these particles can reach Earth only from nearby sources. Yet, the exact nature of these sources, which most likely manifest themselves in the observed anomalies, remains elusive. The many explanations put forward to resolve this case range from standard astrophysics to exotic physics. In this paper, we discuss the possible astrophysical origin of high-energy cosmic-ray electrons through a fully three-dimensional time-dependent Monte Carlo simulation. This approach, which takes advantage of the intrinsic random nature of cosmic-ray diffusive propagation, provides valuable information on the electron-by-electron fluctuations, making it particularly suitable for analyzing in depth the single-source scenario.

On the PeV knee of the cosmic ray spectrum and the TeV cutoff of the electron spectrum

“…Then we can evaluate τ A = 1/n x A 2 ησ P c, and τ e = 1/n x ησ e c. The total life time of CRs confines the total interaction times before arriving at the observer. And it is estimated as τ esc (R) ∼ 2 × 10 8 ( R 1 GV ) −0.6 yr [41] for the nuclei and 10 5 yr [42] for the electron, given that we only concern the electron around 1 TeV. The escape time τ esc (R) depends on the the Boron to Carbon flux ratio measurement.…”

Clues from 4U 0142+61 on supernova fallback disc formation and precession

“…A step forward in the knowledge of pulsar and magnetar environments may also provide precious insights on positron observations in cosmic rays gathered near Earth showing an increasing excess of these particles with respect to the estimated secondary component above 7 GeV, with a drop-off just below 300 GeV and a possible cutoff at about 800 GeV (Aguilar et al 2019;Diesing & Caprioli 2020;Huang et al 2020). While an astrophysical or an exotic origin of the excess of positrons in cosmic rays remains to be settled (see for instance Harding & Ramaty (1987); Zhang & Cheng (2001); Grimani (2004Grimani ( , 2007; Feng & Zhang (2018); Manconi et al (2020)), observations are compatible with sources of TeV e − -e + located between 100 and 800 pc from the Solar System (Attallah 2016).…”

Investigating the origin of high-energy cosmic-ray electrons with Monte Carlo simulation

“…However, the intrinsic random nature of the diffusive propagation of cosmic-ray electrons makes it possible to use Monte Carlo simulation [17]. This approach is particularly suitable at very high energy where only a few sources are expected to dominate the energy spectrum.…”