费米 LAT 测量的弥漫伽马射线背景中的各向异性
高能天体物理现象
2019-08-15 v1 宇宙学与河外天体物理
高能物理 - 唯象学
摘要
未分辨源对弥漫伽马射线背景的贡献可能会在小角尺度上诱导该辐射产生各向异性。我们分析了费米 LAT (Fermi LAT) 在银河纬度 |b| > 30 deg 范围内、跨越 1 至 50 GeV 的四个能段中测得的弥漫辐射的角功率谱。在对应于角尺度 \lesssim 2 deg 的多极矩 \ell \ge 155 处，我们在 1-2 GeV、2-5 GeV 和 5-10 GeV 能段中以 >99.99% 的置信度 (CL) 探测到了高于光子噪声水平的角功率，在 10-50 GeV 能段中则以 >99% 的置信度探测到。在每个能段内，测得的角功率在所有 \ell \ge 155 的多极矩处大致取相同值，这表明其源于一个或多个非成团源群的贡献。归一化为每个能段平均强度的角功率振幅在所有能量下与常数值一致，C_P/<I>^2 = 9.05 +/- 0.84 x 10^{-6} sr，而 C_P 的能量依赖性则与各向异性源于具有谱指数 \Gamma_s = 2.40 +/- 0.07 的幂律光子谱的一个或多个源群相一致。我们讨论了测得的角功率对可能为弥漫伽马射线背景提供贡献的伽马射线源群的启示。
引用
@article{arxiv.1202.2856,
title = {Anisotropies in the diffuse gamma-ray background measured by the Fermi LAT},
author = {M. Ackermann and M. Ajello and A. Albert and L. Baldini and J. Ballet and G. Barbiellini and D. Bastieri and K. Bechtol and R. Bellazzini and E. D. Bloom and E. Bonamente and A. W. Borgland and T. J. Brandt and J. Bregeon and M. Brigida and P. Bruel and R. Buehler and S. Buson and G. A. Caliandro and R. A. Cameron and P. A. Caraveo and C. Cecchi and E. Charles and A. Chekhtman and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and J. Conrad and A. Cuoco and S. Cutini and F. D'Ammando and F. de Palma and C. D. Dermer and S. W. Digel and E. do Couto e Silva and P. S. Drell and A. Drlica-Wagner and R. Dubois and C. Favuzzi and S. J. Fegan and E. C. Ferrara and P. Fortin and Y. Fukazawa and P. Fusco and F. Gargano and D. Gasparrini and S. Germani and N. Giglietto and M. Giroletti and T. Glanzman and G. Godfrey and G. A. Gomez-Vargas and T. Grégoire and I. A. Grenier and J. E. Grove and S. Guiriec and M. Gustafsson and D. Hadasch and M. Hayashida and K. Hayashi and X. Hou and R. E. Hughes and G. Jóhannesson and A. S. Johnson and T. Kamae and J. Knödlseder and M. Kuss and J. Lande and L. Latronico and M. Lemoine-Goumard and T. Linden and A. M. Lionetto and M. Llena Garde and F. Longo and F. Loparco and M. N. Lovellette and P. Lubrano and M. N. Mazziotta and J. E. McEnery and W. Mitthumsiri and T. Mizuno and C. Monte and M. E. Monzani and A. Morselli and I. V. Moskalenko and S. Murgia and M. Naumann-Godo and J. P. Norris and E. Nuss and T. Ohsugi and A. Okumura and M. Orienti and E. Orlando and J. F. Ormes and D. Paneque and J. H. Panetta and D. Parent and V. Pavlidou and M. Pesce-Rollins and M. Pierbattista and F. Piron and G. Pivato and S. Rainò and R. Rando and A. Reimer and O. Reimer and M. Roth and C. Sbarra and J. Schmitt and C. Sgrò and J. Siegal-Gaskins and E. J. Siskind and G. Spandre and P. Spinelli and A. W. Strong and D. J. Suson and H. Takahashi and T. Tanaka and J. B. Thayer and L. Tibaldo and M. Tinivella and D. F. Torres and G. Tosti and E. Troja and T. L. Usher and J. Vandenbroucke and V. Vasileiou and G. Vianello and V. Vitale and A. P. Waite and B. L. Winer and K. S. Wood and M. Wood and Z. Yang and S. Zimmer and E. Komatsu},
journal= {arXiv preprint arXiv:1202.2856},
year = {2019}
}
备注
28 pages, 20 figures; accepted for publication in Phys. Rev. D; Contact authors: A. Cuoco, E. Komatsu, T. Linden, M. N. Mazziotta, J. Siegal-Gaskins, V. Vitale