FERMI LARGE AREA TELESCOPE OBSERVATIONS OF TWO GAMMA-RAY EMISSION COMPONENTS FROM THE QUIESCENT SUN
FERMI LARGE AREA TELESCOPE OBSERVATIONS OF TWO GAMMA-RAY EMISSION COMPONENTS FROM THE QUIESCENT SUN
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费米大面积望远镜对静止太阳的两个伽马射线发射成分的观测
DOI：
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发表时间：
2011
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通讯作者：
M. Ziegler
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作者：
A. Abdo;M. Ackermann;M. Ajello;L. Baldini;J. Ballet;G. Barbiellini;D. Bastieri;K. Bechtol;R. Bellazzini;B. Berenji;E. Bonamente;A. Borgland;A. Bouvier;J. Bregeon;A. Brez;M. Brigida;P. Bruel;R. Buehler;S. Buson;G. Caliandro;R. Cameron;P. Caraveo;J. Casandjian;C. Cecchi;E. Charles;A. Chekhtman;J. Chiang;S. Ciprini;R. Claus;J. Cohen;J. Conrad;S. Cutini;A. Angelis;F. Palma;C. Dermer;S. Digel;E. Silva;P. Drell;R. Dubois;C. Favuzzi;S. Fegan;W. Focke;P. Fortin;M. Frailis;S. Funk;P. Fusco;F. Gargano;D. Gasparrini;N. Gehrels;S. Germani;N. Giglietto;F. Giordano;M. Giroletti;T. Glanzman;G. Godfrey;I. Grenier;L. Grillo;S. Guiriec;D. Hadasch;E. Hays;R. Hughes;G. Iafrate;G. Jóhannesson;A. Johnson;T. Johnson;T. Kamae;H. Katagiri;J. Kataoka;J. Knödlseder;M. Kuss;J. Lande;L. Latronico;Sooheyong Lee;A. Lionetto;F. Longo;F. Loparco;B. Lott;M. Lovellette;P. Lubrano;A. Makeev;M. Mazziotta;J. Mcenery;J. Méhault;P. Michelson;W. Mitthumsiri;T. Mizuno;A. Moiseev;C. Monte;M. Monzani;A. Morselli;I. Moskalenko;S. Murgia;T. Nakamori;M. Naumann;P. Nolan;J. Norris;E. Nuss;T. Ohsugi;A. Okumura;N. Omodei;E. Orlando;J. Ormes;M. Ozaki;D. Paneque;V. Pelassa;M. Pesce;M. Pierbattista;F. Piron;T. Porter;S. Rainò;R. Rando;M. Razzano;A. Reimer;O. Reimer;T. Reposeur;S. Ritz;H. Sadrozinski;T. Schalk;C. Sgro’;G. Share;E. Siskind;P. Smith;G. Spandre;P. Spinelli;M. Strickman;A. Strong;H. Takahashi;Takaaki Tanaka;J. Thayer;J. Thayer;D. Thompson;L. Tibaldo;D. Torres;G. Tosti;A. Tramacere;E. Troja;Y. Uchiyama;T. Usher;J. Vandenbroucke;V. Vasileiou;G. Vianello;N. Vilchez;V. Vitale;A. Vladimirov;A. Waite;Pengfei Wang;B. Winer;K. Wood;Zhirong Yang;M. Ziegler
我们报告了Fermi伽玛射线空间望远镜（Fermi）上的大面积望远镜在任务的前18个月探测到来自静止太阳的高能γ射线。这些观测结果与最近太阳活动低的时期相对应，此时宇宙射线（CRs）引起的辐射是最亮的。这是第一次，观测结果的高统计显著性使得两种成分的清晰分离成为可能：由太阳大气中CR级联引起的太阳盘点状发射和由CR电子在日球层中对太阳光子的逆康普顿（IC）散射引起的扩展发射。观测到的来自太阳盘的积分通量（小于或等于100 MeV）为（4.6±0.2[统计误差]+1.0−0.8[系统误差]）× 10−7 cm−2 s−1，比Seckel等人的“标称”模型预测的高约7倍。相比之下，观测到的从以太阳为中心的20°半径区域扩展发射的积分通量（小于或等于100 MeV），但不包括圆盘本身，(6.8±0.7[stat.]+0.5−0.4[syst.]]) × 10−7 cm−2 s−1，以及观测到的光谱和角分布图，与IC发射的理论预测非常吻合。
We report the detection of high-energy γ-rays from the quiescent Sun with the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope (Fermi) 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]+1.0 − 0.8[systematic error]) × 10−7 cm−2 s−1, 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.]+0.5 − 0.4[syst.]) × 10−7 cm−2 s−1, along with the observed spectrum and the angular profile, is in good agreement with the theoretical predictions for the IC emission.