Cosmic ray positrons from a local, middle-aged supernova remnant

Abstract

We argue that the cosmic ray positron excess observed in ATIC-2, Fermi LAT, PAMELA, HESS and recently in the precision AMS-02 experiment can be attributed to the production in a local, middle-aged supernova remnant (SNR). Using the prediction of our model of cosmic ray acceleration in SNR we estimate that the SNR responsible for the observed positron excess is located between 250 and 320pc from the Sun and is 170-380 kyear old. The most probable candidate for such a source is the SNR which gave birth to the well-known Geminga pulsar, but is no longer visible. Other contenders are also discussed.Comment: 9 pages, 3 figures, accepted by Astroparticle Physic

Gamma-ray emitting supernova remnants as the origin of Galactic cosmic rays?

“…Approaches using discrete, nearby supernova remnants with a generic cosmic ray spectrum with a diffusive transport equation were used in [38] and [39] and could reproduce the observed increasing ratio of positrons to electrons and positrons. Similar results are found in calculations for SNRs from heavy stars [40,41]. The PAMELA data show that the contribution of positrons to the electron and positron spectrum is rising towards higher energies [42], which cannot be explained by the typical results received with the GALPROP code, using a distribution of sources and without including discrete sources in the neighborhood.…”

Secondary cosmic ray nuclei in the light of the single source model and comparison with recent AMS-02 data

“…Wolfendale, 1997, 2005), but the case is not yet fully proven. Recent precise AMS-02 measurements of protons (Aguilar et al, 2015) and helium (Haino for the AMS-02 coll., 2015) spectra, the positron and electron spectra and fractions (Accardo et al, 2014;Aguilar et al, 2014) and antiprotons (Kounine for the AMS coll., 2015) have been explained by us and others in terms of a local, recent single source (Erlykin and Wolfendale, 2013, 2015a, 2015bTomassetti, 2015c). The latest AMS-02 results concerning the B/C ratio (Oliva for the AMS-02 coll., 2015) and Li rigidity spectrum (Derome for the AMS coll., 2015) give the opportunity of a further check on the hypothesis.…”

“…The data were analysed in several earlier papers viz. by Cowsik R. et al, 2014, Tomassetti, 2015a In a set of our own recent papers we analysed the AMS-02 data on the proton and helium energy spectra, positron and antiproton fractions (Erlykin and Wolfendale, 2013, 2015a, 2015b in terms of possible contributions of the local source. In the present paper we examine the possibility of reconciling the B/C ratio and the Li spectrum measured by the AMS-02 experiment with our Single Source Model (SSM).…”

Newly-Discovered Anomalies in Galactic Cosmic Rays: Time for Exotic Scenarios?

“…Regardless of the positron source considered, most of the models have enough "knobs" to fit the data. Some SNR based approaches, e.g., [45] directly use the AMS-02-measured pair of spectral indices to reproduce the U-shape spectrum in Fig.1 by adjusting the weights of the source and background contributions. The position of the spectral minimum also needs to be taken directly from the AMS-02 data.…”