A discovery of a low-energy excess in cosmic-ray iron: an evidence of the past supernova activity in the Local Bubble. (arXiv:2101.12735v2 [astro-ph.HE] UPDATED)

A discovery of a low-energy excess in cosmic-ray iron: an evidence of the past supernova activity in the Local Bubble. (arXiv:2101.12735v2 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Boschini_M/0/1/0/all/0/1">M. J. Boschini</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Torre_S/0/1/0/all/0/1">S. Della Torre</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gervasi_M/0/1/0/all/0/1">M. Gervasi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Grandi_D/0/1/0/all/0/1">D. Grandi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johannesson_G/0/1/0/all/0/1">G. Johannesson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vacca_G/0/1/0/all/0/1">G. La Vacca</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Masi_N/0/1/0/all/0/1">N. Masi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moskalenko_I/0/1/0/all/0/1">I. V. Moskalenko</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pensotti_S/0/1/0/all/0/1">S. Pensotti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Porter_T/0/1/0/all/0/1">T. A. Porter</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quadrani_L/0/1/0/all/0/1">L. Quadrani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rancoita_P/0/1/0/all/0/1">P. G. Rancoita</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rozza_D/0/1/0/all/0/1">D. Rozza</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tacconi_M/0/1/0/all/0/1">M. Tacconi</a>

Since its launch, the Alpha Magnetic Spectrometer – 02 (AMS-02) has delivered
outstanding quality measurements of the spectra of cosmic-ray (CR) species,
$bar{p}$, $e^{pm}$, and nuclei, $_1$H-$_8$O, $_{10}$Ne, $_{12}$Mg, $_{14}$Si,
which resulted in a number of breakthroughs. One of the latest long awaited
surprises is the spectrum of $_{26}$Fe just published by AMS-02. Because of the
large fragmentation cross section and large ionization energy losses, most of
CR iron at low energies is local, and may harbor some features associated with
relatively recent supernova (SN) activity in the solar neighborhood. Our
analysis of new iron spectrum together with Voyager 1 and ACE-CRIS data reveals
an unexpected bump in the iron spectrum and in the Fe/He, Fe/O, and Fe/Si
ratios at 1-2 GV, while a similar feature in the spectra of He, O, Si, and in
their ratios is absent, hinting at a local source of low-energy CRs. The found
excess fits well with recent discoveries of radioactive $^{60}$Fe deposits in
terrestrial and lunar samples, and in CRs. We provide an updated local
interstellar spectrum (LIS) of iron in the energy range from 1 MeV
nucleon$^{-1}$ to $sim$10 TeV nucleon$^{-1}$. Our calculations employ the
GalProp-HelMod framework that is proved to be a reliable tool in deriving the
LIS of CR $bar{p}$, $e^{-}$, and nuclei $Zle28$.

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