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首页> 外文期刊>The Astrophysical journal >SIMULTANEOUS CONSTRAINTS ON THE SPECTRUM OF THE EXTRAGALACTIC BACKGROUND LIGHT AND THE INTRINSIC TeV SPECTRA OF MARKARIAN 421, MARKARIAN 501, AND H1426+428
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SIMULTANEOUS CONSTRAINTS ON THE SPECTRUM OF THE EXTRAGALACTIC BACKGROUND LIGHT AND THE INTRINSIC TeV SPECTRA OF MARKARIAN 421, MARKARIAN 501, AND H1426+428

机译：同时限制了MARKARIAN 421，MARKARIAN 501和H1426 + 428的银河外背景光谱和内在TeV光谱

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摘要

Very high energy (～TeV) γ-rays from blazars are attenuated by photons from the extragalactic background light (EBL). Observations of blazars can therefore provide an ideal opportunity for determining the EBL intensity if their intrinsic spectrum is known. Conversely, knowledge of the EBL intensity can be used to determine the intrinsic blazar spectrum. Unfortunately, neither the EBL intensity nor the intrinsic blazar spectrum is known with high enough precision to accurately derive one quantity from the other. In this paper we use the most recent data on the EBL to construct 12 different realizations representing all possible permutations between EBL limits and the detections in the different wavelength regions. These realizations explore a significantly larger range of allowable EBL spectra than any previous studies. We show that these realizations can be used to explore the effects of the EBL on the inferred spectra of blazars. Concentrating on the two relatively nearby (z ≈ 0.03) blazars Mrk 421 and 501, we derive their intrinsic spectra and peak γ-ray energies for the different EBL realizations. Some EBL spectra give rise to "unphysical" intrinsic blazar spectra, characterized by an exponential rise at high TeV energies. We use the F-test to show that some of these exponential rises are statistically insignificant. Consequently, statements regarding the existence of an "IR background-TeV γ-ray crisis" are unfounded on the basis of our present knowledge of the EBL. EBL spectra that do give rise to unphysical blazar spectra are regarded as invalid realizations of the EBL. Those that do not thus define new constraints on the EBL spectrum and are used to derive new limits on the intensity and the peak γ-ray energy of these two blazars. In particular, we derive an upper limit of ～15 nW m~(-2) sr~(-1) on the 60 μm EBL intensity and find the peak energies of the Mrk 421 and Mrk 501 sources to be very similar, between 0.5-1.2 and 0.8-2.5 TeV, respectively. We also show that the intrinsic spectrum of Mrk 421 during a period of intense flaring activity has a peak energy that seems to shift to higher energies at higher flux states. For the most distant blazar H1426+428 (z = 0.129), most EBL realizations give rise to spectra that peak between ～1 and 5 TeV, with some suggesting peaks below 400 GeV and above ～ 10 TeV. These results provide important constraints on the different particle acceleration mechanisms and the generation of the γ-ray emission. Finally, we also show that uncertainties in the absolute calibration of the γ-ray energies with atmospheric Cerenkov telescopes have an important impact on the intrinsic blazar spectra. These systematic uncertainties will be improved with the next generations of telescopes that will also cover a wider range of γ-ray energies, providing further insights into the intrinsic spectrum of TeV blazars.
机译：来自银河系的极高能量（〜TeV）的γ射线被银河外背景光（EBL）的光子衰减。因此，如果已知其内在光谱，则对Blazar的观测可以为确定EBL强度提供理想的机会。相反，可以将EBL强度的知识用于确定内在的Blazar光谱。不幸的是，EBL强度和固有的易爆谱都不够精确，无法准确地从另一个推导一个量。在本文中，我们使用EBL上的最新数据来构建12种不同的实现，这些实现表示EBL极限与不同波长区域中的检测之间的所有可能排列。这些认识比以前的研究探索了更大的允许EBL光谱范围。我们表明，这些认识可用于探索EBL对blazar推断光谱的影响。集中于两个相对较近的（z≈0.03）blazar Mrk 421和501，我们推导了它们的固有光谱和针对不同EBL实现的峰值γ射线能量。一些EBL光谱会产生“非物理的”固有易爆谱，其特征是在高TeV能量下呈指数上升。我们使用F检验表明，这些指数上升中的一些在统计上是微不足道的。因此，根据我们目前对EBL的了解，没有关于“ IR背景-TeVγ射线危机”存在的陈述。确实会产生非物理的易爆谱的EBL光谱被视为EBL的无效实现。因此，那些并没有在EBL光谱上定义新的限制条件，而是被用来推导这两种blazar的强度和峰值γ射线能量的新限制。特别是，我们推导了60μmEBL强度的〜15 nW m〜（-2）sr〜（-1）的上限，发现Mrk 421和Mrk 501源的峰值能量非常相似，介于0.5之间TeV分别为-1.2和0.8-2.5 TeV。我们还显示，在激烈的燃烧过程中，Mrk 421的本征谱具有峰值能量，该峰值能量似乎在较高的通量状态下转换为较高的能量。对于最遥远的blazar H1426 + 428（z = 0.129），大多数EBL实现产生的光谱峰值在1-5 TeV之间，其中一些表明峰值在400 GeV以下且在-10 TeV以上。这些结果对不同的粒子加速机制和γ射线发射的产生提供了重要的约束。最后，我们还表明，使用大气切伦科夫望远镜对γ射线能量进行绝对校准的不确定性对固有的Blazar光谱具有重要影响。这些系统的不确定性将通过下一代望远镜得到改善，这些望远镜还将覆盖更广范围的γ射线能量，从而进一步了解TeV blazar的固有光谱。

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