A unified picture for three different cosmic-ray observables.

Abstract

We present here a unified scenario that connects three peculiar spectral features recently reported in the spectra of charged cosmic rays (CRs). The spectral hardening measured by AMS-02 in the hadronic spectra above ∼ 250 GeV is here interpreted as a diffusion imprint, and modeled by means of a transport coefficient that smoothly hardens with rigidity. We implement such propagation framework to solve the transport equation with the DRAGON2 numerical code in order to determine the large-scale contribution to the CR fluxes. On top of this solution we explore the hypothesis of a nearby, hidden Supernova Remnant (SNR) to be responsible for the high-energy (above ∼ 100 GeV) all-lepton flux, in particular for the spectral break consistently measured by all the space-and ground-based detectors around 1 TeV. We compute such contribution analytically adopting the same propagation setup implemented for the large-scale background. Simultaneously, we find the signature of the same source in the peculiar bump structure observed by the DAMPE Collaboration in the proton spectrum, consisting of a strong hardening at ∼ 500 GeV and a softening at 13 TeV. We validate our hypothesis with the CR dipole-anisotropy (DA) amplitude and phase. In particular, we interpret the high-energy data (above 10 TeV) pointing towards the Galactic Center as the convolution of the directional fluxes of the large-scale-background sources, whereas the DA amplitude below that energy is compatible with the predictions of our model and is therefore considered as a signature of the nearby SNR that we invoke.

Rapporteur Talk: Cosmic Ray Direct

“…The contributions to this modelling discussed at this ICRC can be classified into two groups: those that explain the flux between hundreds of GeV up to a few TeV as dominated by a single source and those that explain it by a population of sources. Among the single source scenarios, the objects considered comprise the Vela SNR [23] and a potential, unknown, nearby source [24,25]. Among the population scenarios, the objects considered are pulsar wind nebulae [26][27][28], intrabinary shocks of compact binary millisecond pulsars [29], and old supernova remnants (SNRs) [30].…”