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@ARTICLE{Acharyya:639807,
      author       = {Acharyya, A. and Adelfio, A. and Ajello, M. and Baldini, L.
                      and Bartolini, C. and Bastieri, D. and Becerra Gonzalez, J.
                      and Bellazzini, R. and Berenji, B. and Bissaldi, E. and
                      Blandford, R. D. and Bonino, R. and Bottacini, E. and Buson,
                      Sara and Cameron, R. A. and Caraveo, P. A. and Casaburo, F.
                      and Casini, F. and Cavazzuti, E. and Cerasole, D. and
                      Cibrario, N. and Ciprini, S. and Cozzolongo, G. and
                      Orestano, P. Cristarella and Cuna, F. and Cuoco, A. and
                      Cutini, S. and D'Ammando, F. and Depalo, D. and Digel, S. W.
                      and Di Lalla, N. and Di Venere, L. and Domínguez, A. and
                      Fiori, A. and Fukazawa, Y. and Fusco, P. and Gargano, F. and
                      Gasbarra, C. and Gasparrini, D. and Germani, S. and
                      Giacchino, F. and Giglietto, N. and Giliberti, M. and
                      Giordano, F. and Giroletti, M. and Guiriec, S. and Gupta, R.
                      and Hashizume, M. and Hays, E. and Hewitt, J. W. and
                      Airasca, A. Holzmann and Horan, D. and Hou, X. and Kayanoki,
                      T. and Kuss, M. and Larsson, S. and Laviron, A. and Li, J.
                      and Liguori, A. and Liodakis, I. and Loizzo, P. and Longo,
                      F. and Loparco, F. and Lopez Perez, S. and Lorusso, L. and
                      Lovellette, M. N. and Lubrano, P. and Maldera, S. and
                      Manfreda, A. and Martí-Devesa, G. and Martinelli, R. and
                      Mazziotta, M. N. and McEnery, J. E. and Mereu, I. and
                      Michailidis, M. and Michelson, P. F. and Mirabal, N. and
                      Mizuno, T. and Monti-Guarnieri, P. and Monzani, M. E. and
                      Morselli, A. and Moskalenko, I. V. and Negro, M. and Omodei,
                      N. and Orlando, E. and Ormes, J. F. and Paneque, D. and
                      Panzarini, G. and Persic, M. and Pesce-Rollins, M. and
                      Petrosian, V. and Pillera, R. and Principe, G. and Raino, S.
                      and Rando, R. and Rani, B. and Razzano, M. and Reimer, A.
                      and Reimer, O. and Sanchez-Conde, M. and Saz Parkinson, P.
                      M. and Serini, D. and Sgro, C. and Siskind, E. J. and
                      Spinelli, P. and Tak, D. and Tibaldo, L. and Torres, D. F.
                      and Valverde, J. and Wadiasingh, Z. and Zhang, W.},
      title        = {{P}uzzling {V}ariation of {G}amma {R}ays from the {S}un
                      over the {S}olar {C}ycle {R}evealed with {F}ermi-{LAT}},
      journal      = {The astrophysical journal / Part 2},
      volume       = {989},
      number       = {1},
      issn         = {2041-8205},
      address      = {London},
      publisher    = {Institute of Physics Publ.},
      reportid     = {PUBDB-2025-04680, arXiv:2505.06348},
      pages        = {L16},
      year         = {2025},
      note         = {Accepted for publication in ApJL. Contact authors: Nicola
                      Giglietto, Elena Orlando, Silvia Raino'},
      abstract     = {The steady-state gamma-ray emission from the Sun is thought
                      to consist of two emission components due to interactions
                      with Galactic cosmic rays: (1) a hadronic disk component,
                      and (2) a leptonic extended component peaking at the solar
                      edge and extending into the heliosphere. The flux of these
                      components is expected to vary with the 11 yr solar cycle,
                      being highest during solar minimum and lowest during solar
                      maximum, as it varies with the cosmic-ray flux. No study has
                      yet analyzed the flux variation of each component over solar
                      cycles. In this work, we measure the temporal variations of
                      the flux of each component over 15 yr of Fermi Large Area
                      Telescope observations and compare them with the sunspot
                      number and Galactic cosmic-ray flux from AMS-02 near Earth.
                      We find that the flux variation of the disk anticorrelates
                      with the sunspot number and correlates with cosmic-ray
                      protons, as expected, confirming its emission mechanism. In
                      contrast, the extended component exhibits a more complex
                      variation: despite an initial anticorrelation with the
                      sunspot number, we find neither anticorrelation with the
                      sunspot number nor correlation with cosmic-ray electrons
                      over the full 15 yr period. This most likely suggests that
                      cosmic-ray transport and modulation in the inner heliosphere
                      are unexpectedly complex and may differ for electrons and
                      protons or, alternatively, that there is an additional,
                      unknown component of gamma rays or cosmic rays. These
                      findings impact space weather research and emphasize the
                      need for close monitoring of Cycle 25 and the ongoing
                      polarity reversal.},
      cin          = {$Z_GA$},
      ddc          = {520},
      cid          = {$I:(DE-H253)Z_GA-20210408$},
      pnm          = {613 - Matter and Radiation from the Universe (POF4-613)},
      pid          = {G:(DE-HGF)POF4-613},
      experiment   = {EXP:(DE-MLZ)NOSPEC-20140101},
      typ          = {PUB:(DE-HGF)16},
      eprint       = {2505.06348},
      howpublished = {arXiv:2505.06348},
      archivePrefix = {arXiv},
      SLACcitation = {$\%\%CITATION$ = $arXiv:2505.06348;\%\%$},
      doi          = {10.3847/2041-8213/adef4d},
      url          = {https://bib-pubdb1.desy.de/record/639807},
}