标题： 确定耀变体中GeV辐射的位置 显示英文标题

标题： Determining the location of the GeV emission in powerful blazars

摘要： 目前文献中正在讨论的一个问题是，费米观测到的耀变体的GeV辐射是在距离黑洞多远的地方产生的。 本文介绍了一种诊断工具，用于检验GeV辐射源是否位于亚pc尺度的宽发射线区（BLR）内，还是位于更大尺度的pc分子环（MT）环境中。 在BLR内部，散射发生在Klein-Nishina效应开始时，导致电子冷却时间几乎与能量无关，因此，预期高能辐射的变化将是无色散的。 相反，如果辐射源位于BLR外部，则预期GeV变化与能量有关，并且幅度随能量增加。 我们通过耀变体变化的时间依赖性数值模拟来演示这一点，并讨论了我们方法的适用性。 显示英文摘要

摘要： An issue currently under debate in the literature is how far from the black hole is the Fermi-observed GeV emission of powerful blazars emitted. Here we present a diagnostic tool for testing whether the GeV emission site is located within the sub-pc broad emission line (BLR) region or further out in the pc scale molecular torus (MT) environment. Within the BLR the scattering takes place at the onset of the Klein-Nishina regime, causing the electron cooling time to become almost energy independent and as a result, the variation of high-energy emission is expected to be achromatic. Contrarily, if the emission site is located outside the BLR, the expected GeV variability is energy-dependent and with amplitude increasing with energy. We demonstrate this using time-dependent numerical simulations of blazar variability and discuss the applicability of our method.