利用 MAGIC-I 望远镜对 PKS 2155-304 的大天顶角观测
高能天体物理现象
2015-06-05 v1 宇宙学与河外天体物理
摘要
高频峰 BL Lac 天体 PKS 2155-304（红移 z=0.116）于 1997 年被澳大利亚 Durham 大学 Mark VI 伽马射线 Cherenkov 望远镜在甚高能（VHE, E >100GeV）伽马射线波段发现，其通量相当于 Crab 星云通量的 20%。随后它被南半球 Cherenkov 望远镜 H.E.S.S. 观测并以高显著性探测到。由于大天顶角下观测条件极具挑战性，从北半球进行探测十分困难。2006 年 7 月，H.E.S.S. 合作组报告了一次异常的 VHE 伽马射线爆发。在爆发期间，发现 VHE 伽马射线发射在分钟时间尺度上具有变化性，且平均通量约为观测到的 Crab 星云通量的 7 倍。这次异常爆发触发了使用 MAGIC-I 单台 Cherenkov 望远镜的后续观测，PKS 2155-304 于 2006 年 7 月 28 日至 8 月 2 日期间在大天顶角下被观测了 15 小时。在此我们展示了对该源在异常耀斑之后行为的研究，以及一种针对大天顶角数据的增强分析方法。我们开发了改进的事件选择方法，从而实现了更好的背景抑制。我们导出的平均能谱在 400GeV 以上谱指数为 -3.5 +/- 0.2，这与 H.E.S.S. 在 MJD 53944 主耀斑期间测量的谱形状非常吻合。此外，我们还展示了 PKS 2155-304 的谱能量分布建模。通过我们的观测，我们增加了该源的占空比，扩展了 H.E.S.S. 在爆发后导出的光变曲线。最后，我们发现了最大幅度为三到四倍的逐夜变化性，以及在其中一夜（MJD 53945）具有相似幅度的夜内变化性。
引用
@article{arxiv.1207.1634,
title = {High zenith angle observations of PKS 2155-304 with the MAGIC-I telescope},
author = {The MAGIC Collaboration and J. Aleksić and L. A. Antonelli and P. Antoranz and M. Asensio and U. Barres de Almeida and J. A. Barrio and J. Becerra González and W. Bednarek and K. Berger and E. Bernardini and A. Biland and O. Blanch and R. K. Bock and A. Boller and G. Bonnoli and D. Borla Tridon and T. Bretz and E. Carmona and A. Carosi and P. Colin and E. Colombo and J. L. Contreras and J. Cortina and L. Cossio and S. Covino and P. Da Vela and F. Dazzi and A. De Angelis and G. De Caneva and E. De Cea del Pozo and B. De Lotto and C. Delgado Mendez and A. Diago Ortega and M. Doert and D. Dominis Prester and D. Dorner and M. Doro and D. Eisenacher and D. Elsaesser and D. Ferenc and M. V. Fonseca and L. Font and C. Fruck and R. J. García López and M. Garczarczyk and D. Garrido Terrats and M. Gaug and G. Giavitto and N. Godinović and A. González Muñoz and S. R. Gozzini and A. Hadamek and D. Hadasch and D. Häfner and A. Herrero and J. Hose and D. Hrupec and B. Huber and F. Jankowski and T. Jogler and V. Kadenius and S. Klepser and M. L. Knoetig and T. Krähenbühl and J. Krause and J. Kushida and A. La Barbera and D. Lelas and E. Leonardo and N. Lewandowska and E. Lindfors and S. Lombardi and M. López and R. López-Coto and A. López-Oramas and E. Lorenz and M. Makariev and G. Maneva and N. Mankuzhiyil and K. Mannheim and L. Maraschi and B. Marcote and M. Mariotti and M. Martínez and D. Mazin and M. Meucci and J. M. Miranda and R. Mirzoyan and J. Moldón and A. Moralejo and P. Munar-Adrover and A. Niedzwiecki and D. Nieto and K. Nilsson and N. Nowak and R. Orito and S. Paiano and M. Palatiello and D. Paneque and R. Paoletti and J. M. Paredes and S. Partini and M. Persic and M. Pilia and J. Pochon and F. Prada and P. G. Prada Moroni and E. Prandini and I. Puljak and I. Reichardt and R. Reinthal and W. Rhode and M. Ribó and J. Rico and S. Rügamer and A. Saggion and K. Saito and T. Y. Saito and M. Salvati and K. Satalecka and V. Scalzotto and V. Scapin and C. Schultz and T. Schweizer and S. N. Shore and A. Sillanpää and J. Sitarek and I. Snidaric and D. Sobczynska and F. Spanier and S. Spiro and V. Stamatescu and A. Stamerra and B. Steinke and J. Storz and S. Sun and T. Surić and L. Takalo and H. Takami and F. Tavecchio and P. Temnikov and T. Terzić and D. Tescaro and M. Teshima and O. Tibolla and D. F. Torres and T. Toyama and A. Treves and M. Uellenbeck and P. Vogler and R. M. Wagner and Q. Weitzel and V. Zabalza and F. Zandanel and R. Zanin},
journal= {arXiv preprint arXiv:1207.1634},
year = {2015}
}
备注
10 pages, 9 figures; Accepted for publication in A&A