<i>Fermi</i> Large Area Telescope observations of two gamma-ray emission components from the quiescent sun [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 2011. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- Article numbers 116 : digital, PDF file
- Additional Creators:
- SLAC National Accelerator Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Here, we report the detection of high-energy γ-rays from the quiescent Sun with the Large Area Telescope on board the <i>Fermi Gamma-Ray Space Telescope</i> (<i>Fermi</i>) during the first 18 months of the mission. These observations correspond to the recent period of low solar activity when the emission induced by cosmic rays (CRs) is brightest. For the first time, the high statistical significance of the observations allows clear separation of the two components: the point-like emission from the solar disk due to CR cascades in the solar atmosphere and extended emission from the inverse Compton (IC) scattering of CR electrons on solar photons in the heliosphere. The observed integral flux (≥100 MeV) from the solar disk is (4.6 ± 0.2[statistical error]<sup>+1.0</sup> <sub>–0.8</sub>[systematic error]) × 10<sup>–7</sup> cm<sup>–2</sup> s<sup>–1</sup>, which is ~7 times higher than predicted by the "nominal" model of Seckel et al. In contrast, the observed integral flux (≥100 MeV) of the extended emission from a region of 20° radius centered on the Sun, but excluding the disk itself, (6.8 ± 0.7[stat.]<sup>+0.5</sup> <sub>– 0.4</sub>[syst.]) × 10<sup>–7</sup> cm<sup>–2</sup> s<sup>–1</sup>, along with the observed spectrum and the angular profile, is in good agreement with the theoretical predictions for the IC emission.
- Published through SciTech Connect., 06/06/2011., Astrophysical Journal 734 2 ISSN 0004-637X AM, and Abdo, A.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bonamente, E.; Borgland, A.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G.; Cameron, R.; Caraveo, P.; Casandjian, J.; Cecchi, C.; Charles, E.; et al.
- Funding Information:
View MARC record | catkey: 23496613