Bulk Comptonization of the Cosmic Microwave Background by Extragalactic Jets as a Probe of Their Matter Content
Bulk Comptonization of the Cosmic Microwave Background by Extragalactic Jets as a Probe of Their Matter Content
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通过河外喷流对宇宙微波背景进行整体压缩作为其物质含量的探测
DOI：
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发表时间：
2005
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影响因子：
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通讯作者：
F. Stecker
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作者：
M. Georganopoulos;D. Kazanas;E. Perlman;F. Stecker
我们提出了一种估计组成的方法，即，轻子和质子的相对数量，在千秒差距尺度的喷流中显示出X射线明亮的星系外喷流。该方法依赖于测量，或设置上限，宇宙微波背景（CMB）辐射的组成部分，是由相对论流动射流中的冷电子体康普顿化（BC）。这些测量，沿着宽带结发射的建模，约束喷流的体洛伦兹因子Γ，可以产生质子和轻子携带的喷流功率的估计。我们提供了一个明确的计算光谱的BC CMB组件，并将这些结果应用到PKS 0637-752和3C 273，两个超光速类星体与钱德拉探测到的大规模喷流。使这些源特别适合于这样一个过程的是在“桥”中没有显著的非热喷流发射，“桥”是核心和第一个明亮的喷流结之间的区域，这保证了那里的大多数电子是冷的，留下BC散射的CMB辐射作为该区域唯一重要的光子源。在λ = 3.6-8.0 μm处，最有可能观察到BC散射CMB发射的波段，斯皮策角分辨率（~ 1 '-3'）比这些喷流的桥（~ 10 '）小得多，使得测量和分辨这种发射成为可能。
We propose a method for estimating the composition, i.e., the relative amounts of leptons and protons, of extragalactic jets that exhibit X-ray-bright knots in their kiloparsec-scale jets. The method relies on measuring, or setting upper limits on, the component of the cosmic microwave background (CMB) radiation that is bulk Comptonized (BC) by cold electrons in the relativistically flowing jet. These measurements, along with modeling of the broadband knot emission that constrains the bulk Lorentz factor Γ of the jets, can yield estimates of the jet power carried by protons and leptons. We provide an explicit calculation of the spectrum of the BC CMB component and apply these results to PKS 0637-752 and 3C 273, two superluminal quasars with Chandra-detected large-scale jets. What makes these sources particularly suited for such a procedure is the absence of significant nonthermal jet emission in the "bridge," the region between the core and the first bright jet knot, which guarantees that most of the electrons there are cold, leaving the BC-scattered CMB radiation as the only significant source of photons in this region. At λ = 3.6-8.0 μm, the most likely band to observe the BC-scattered CMB emission, the Spitzer angular resolution (~1'-3') is considerably smaller than the bridges of these jets (~10'), making it possible to both measure and resolve this emission.