Jul 6 – 13, 2022
Bologna, Italy
Europe/Rome timezone

Spectra of Cosmic Ray Fluorine, Sodium and Aluminum and the Hints of Low-energy Excesses

Jul 7, 2022, 7:00 PM
15m
Room 8 (Blu)

Room 8 (Blu)

Parallel Talk Astroparticle Physics and Cosmology Astroparticle Physics and Cosmology

Speaker

Nicolò Masi (Istituto Nazionale di Fisica Nucleare)

Description

Since its launch, the Alpha Magnetic Spectrometer-02 (AMS-02) has delivered outstanding quality measurements of the spectra of cosmic-ray (CR) species, which resulted in a number of breakthroughs. Some of the most recent AMS-02 results are the measurements of the spectra of CR fluorine, sodium and aluminum up to 2 TV. Given their low solar system abundances, a significant fraction of each element is produced in fragmentations of heavier species, predominantly Ne, Mg, and Si. Using AMS-02 together with ACE-CRIS and Voyager 1 data, our calculations within the GALPROP–HELMOD framework provided updated local interstellar spectra (LIS) for these species, in the rigidity range from few MV to few TV. While the sodium spectrum agrees well with the predictions, fluorine and aluminum LIS show excesses below 10 GV, hinting at primary components. In this context, the origin of other previously found excesses in Li and Fe is discussed. The observed excesses in Li, F, and Al appear to be consistent with the local Wolf-Rayet stars hypothesis, invoked to reproduce anomalous 22Ne/20Ne, 12C/16O, and 58Fe/56Fe ratios in CRs, while excess in Fe is likely connected with a past supernovae activity in the solar neighborhood.

In-person participation Yes

Primary author

Nicolò Masi (Istituto Nazionale di Fisica Nucleare)

Co-authors

Davide Grandi (MIB) Davide Rozza (LNS) Dr G. Jóhannesson (Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland NORDITA, Roslagstullsbacken 23, 106 91 Stockholm, Sweden) Giuseppe La Vacca (Istituto Nazionale di Fisica Nucleare) Prof. I.V. Moskalenko (Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305; Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305) Lucio Quadrani (Istituto Nazionale di Fisica Nucleare) Massimo Gervasi (MIB) Matteo Jeroen Boschini Dr Mauro Tacconi (INFN, Milano-Bicocca, Milano, Italy; Physics Department, University of Milano-Bicocca, Milano, Italy) Pier Giorgio Rancoita (MIB) Dr S. Pensotti (INFN, Milano-Bicocca, Milano, Italy; Physics Department, University of Milano-Bicocca, Milano, Italy) Stefano Della Torre (Istituto Nazionale di Fisica Nucleare) Dr T.A. Porter (Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305; Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305)

Presentation materials