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Résumé |
I will discuss recent results on gamma-ray observations of the Sun with Fermi,
which revealed many interesting and surprising features. These gamma rays are
expected to be produced by hadronic interactions between cosmic rays and the
solar atmosphere. The high flux of gamma rays observed from the Sun requires a
large boost of gamma-ray production by some mechanism, which is likely related
to solar magnetic fields. Our new results include the first resolved image of
the Sun and a mysterious dip in the spectrum between 30-50 GeV. In particular,
we also find that the solar gamma-ray spectrum during solar minimum is hard
(~E−2.1) and reaches at least 200 GeV. This suggests that ground based
experiments like HAWC and LHAASO will be important for probing the Sun at TeV
regime. Understanding solar gamma rays is crucial for predicting the solar
atmospheric neutrino flux, which can potentially be detected by IceCube/KM3NeT,
and is important for many aspects of solar dark matter searches.
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