HESS J1943+213：一个候选的极端 BL Lacertae 天体
高能天体物理现象
2016-08-14 v1
摘要
我们报告了一个新探测到的位于银道面的点状源 HESS J1943+213。该源与一个未证认的硬 X 射线源 IGR J19443+2117 重合，后者被认为具有射电和红外对应体。HESS J1943+213 的探测显著性水平为 7.9 \sigma（试验后），位置为 RA(J2000)=19h 43m 55s +- 1s (stat) +- 1s (sys)，DEC(J2000) = +21deg 18' 8" +- 17" (stat) +- 20" (sys)。该源具有软谱，光子指数 Gamma = 3.1 +- 0.3 (stat) +- 0.2 (sys)，470 GeV 以上的流量为 1.3 +- 0.2 (stat) +- 0.3 (sys) x 10^{-12} cm^{-2} s^{-1}。在 0.1-100 GeV 能段内，低至 6 x 10^{-9} cm^{-2} s^{-1} 的流量极限处没有 Fermi/LAT 对应体（该 95% 置信度上限是针对假设光子指数 Gamma=2.0 的幂律模型计算的）。从射电到甚高能 (VHE) 伽马射线的数据未显示任何显著的光变。我们将新的 H.E.S.S.、Fermi/LAT 和 Nancay 射电望远镜观测与 IGR J19443+2117 已有的非同时多波段观测相结合，讨论了可能的源关联，以及将其解释为活动星系核、伽马射线双星或脉冲星风云星云的可能性。缺乏大质量恒星对应体不利于双星假说，而甚高能软谱在脉冲星风云星云的情况下将是非常反常的。此外，对银河系内对应体的距离估计表明它们位于银河系之外。所有可用观测均支持将其解释为红移 z>0.14 的极端高频峰 BL Lac 天体。这将是首次通过地面 VHE 观测偶然探测到耀变体，也是首次在银道面内探测到 VHE AGN。
引用
@article{arxiv.1103.0763,
title = {HESS J1943+213: a candidate extreme BL Lacertae object},
author = {H. E. S. S. Collaboration and : and A. Abramowski and F. Acero and F. Aharonian and A. G. Akhperjanian and G. Anton and A. Balzer and A. Barnacka and U. Barres de Almeida and A. R. Bazer-Bachi and Y. Becherini and J. Becker and B. Behera and K. Bernlöhr and A. Bochow and C. Boisson and J. Bolmont and P. Bordas and V. Borrel and J. Brucker and F. Brun and P. Brun and T. Bulik and I. Büsching and S. Carrigan and S. Casanova and M. Cerruti and P. M. Chadwick and A. Charbonnier and R. C. G. Chaves and A. Cheesebrough and L. -M. Chounet and A. C. Clapson and G. Coignet and P. Colom and J. Conrad and M. Dalton and M. K. Daniel and I. D. Davids and B. Degrange and C. Deil and H. J. Dickinson and A. Djannati-Ataï and W. Domainko and L. O'C. Drury and F. Dubois and G. Dubus and J. Dyks and M. Dyrda and K. Egberts and P. Eger and P. Espigat and L. Fallon and C. Farnier and S. Fegan and F. Feinstein and M. V. Fernandes and A. Fiasson and G. Fontaine and A. Förster and M. Füßling and Y. A. Gallant and H. Gast and L. Gérard and D. Gerbig and B. Giebels and J. F. Glicenstein and B. Glück and P. Goret and D. Göring and S. Häffner and J. D. Hague and D. Hampf and M. Hauser and S. Heinz and G. Heinzelmann and G. Henri and G. Hermann and J. A. Hinton and A. Hoffmann and W. Hofmann and P. Hofverberg and M. Holler and D. Horns and A. Jacholkowska and O. C. de Jager and C. Jahn and M. Jamrozy and I. Jung and M. A. Kastendieck and K. Katarzyński and U. Katz and S. Kaufmann and D. Keogh and D. Khangulyan and B. Khélifi and D. Klochkov and W. Kluźniak and T. Kneiske and Nu. Komin and K. Kosack and R. Kossakowski and H. Laffon and G. Lamanna and D. Lennarz and T. Lohse and A. Lopatin and C. -C. Lu and V. Marandon and A. Marcowith and J. Masbou and D. Maurin and N. Maxted and T. J. L. McComb and M. C. Medina and J. Méhault and N. Nguyen and R. Moderski and E. Moulin and C. L. Naumann and M. Naumann-Godo and M. de Naurois and D. Nedbal and D. Nekrassov and B. Nicholas and J. Niemiec and S. J. Nolan and S. Ohm and J-F. Olive and E. de Oña Wilhelmi and B. Opitz and M. Ostrowski and M. Panter and M. Paz Arribas and G. Pedaletti and G. Pelletier and P. -O. Petrucci and S. Pita and G. Pühlhofer and M. Punch and A. Quirrenbach and M. Raue and S. M. Rayner and A. Reimer and O. Reimer and M. Renaud and R. de los Reyes and F. Rieger and J. Ripken and L. Rob and S. Rosier-Lees and G. Rowell and B. Rudak and C. B. Rulten and J. Ruppel and F. Ryde and V. Sahakian and A. Santangelo and R. Schlickeiser and F. M. Schöck and A. Schönwald and A. Schulz and U. Schwanke and S. Schwarzburg and S. Schwemmer and A. Shalchi and M. Sikora and J. L. Skilton and H. Sol and G. Spengler and Ł. Stawarz and R. Steenkamp and C. Stegmann and F. Stinzing and K. Stycz and I. Sushch and A. Szostek and J. -P. Tavernet and R. Terrier and O. Tibolla and M. Tluczykont and K. Valerius and C. van Eldik and G. Vasileiadis and C. Venter and J. P. Vialle and A. Viana and P. Vincent and M. Vivier and H. J. Völk and F. Volpe and S. Vorobiov and M. Vorster and S. J. Wagner and M. Ward and A. Wierzcholska and A. Zajczyk and A. A. Zdziarski and A. Zech and H. -S. Zechlin and T. H. Burnett and A. B. Hill},
journal= {arXiv preprint arXiv:1103.0763},
year = {2016}
}
备注
10 pages, 7 figures, in press at A&A