H.E.S.S. discovery of very high energy γ-ray emission from PKS 0625−354
H.E.S.S. discovery of very high energy γ-ray emission from PKS 0625−354
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H.E.S.S.
DOI：
10.1093/mnras/sty439
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发表时间：
2018
影响因子：
4.8
通讯作者：
Backes, M
中科院分区：
文献类型：
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作者：
Abdalla, H;Abramowski, A;Aharonian, F;Ait Benkhali, F;Akhperjanian, A G;Andersson, T;Angüner, E O;Arrieta, M;Aubert, P;Backes, M
2012 年，用四台高能立体系统 (H.E.S.S.) 望远镜在 5.5 小时内观测到 PKS 0625−354 (z= 0.055)。检测到该源的能量阈值高于 200 GeV，显着性水平为 6.1σ。这些观察结果没有发现显着的变异性。源用幂律谱很好地描述，光子指数 Г = 2.84 ± 0.50stat± 0.10sysstand 归一化 (atE0= 1.0 TeV)N0(E0) = (0.58 ± 0.22stat± 0.12syst) × 10−12TeV−1cm−2s−1。还分析了使用 Fermi-LAT、Swift-XRT、Swift-UVOT、ATOM 和 WISE 收集的多波长数据。仅在 Fermi-LAT γ 射线和 Swift-XRT X 射线能带中观察到显着的变化。拥有从无线电到极高能量的良好多波长覆盖，我们对两种类型的发射场景进行了宽带建模。对单区轻子强子模型和多区轻子模型的结果进行了比较和讨论。根据能量学，我们的分析支持轻子多区模型。与 X 射线变异性约束相关的模型支持之前的结果，表明 PKS 0625−354 具有 BL Lac 性质，但具有射电星系典型的大规模喷流结构。
PKS 0625−354 (z= 0.055) was observed with the four High Energy Stereoscopic System (H.E.S.S.) telescopes in 2012 during 5.5 h. The source was detected above an energy threshold of 200 GeV at a significance level of 6.1σ. No significant variability is found in these observations. The source is well described with a power-law spectrum with photon index Γ = 2.84 ± 0.50stat± 0.10systand normalization (atE0= 1.0 TeV)N0(E0) = (0.58 ± 0.22stat± 0.12syst) × 10−12TeV−1cm−2s−1. Multiwavelength data collected withFermi-LAT,Swift-XRT,Swift-UVOT,ATOMandWISEare also analysed. Significant variability is observed only in theFermi-LAT γ-ray andSwift-XRT X-ray energy bands. Having a good multiwavelength coverage from radio to very high energy, we performed a broad-band modelling from two types of emission scenarios. The results from a one zone lepto-hadronic and a multizone leptonic models are compared and discussed. On the grounds of energetics, our analysis favours a leptonic multizone model. Models associated to the X-ray variability constraint support previous results, suggesting a BL Lac nature of PKS 0625−354 with, however, a large-scale jet structure typical of a radio galaxy.