FERMI RULES OUT THE INVERSE COMPTON/CMB MODEL FOR THE LARGE-SCALE JET X-RAY EMISSION OF 3C 273
FERMI RULES OUT THE INVERSE COMPTON/CMB MODEL FOR THE LARGE-SCALE JET X-RAY EMISSION OF 3C 273
复制标题
DOI：
10.1088/2041-8205/780/2/l27
复制
发表时间：
2013-07
期刊：
影响因子：
--
通讯作者：
E. Meyer;M. Georganopoulos
中科院分区：
文献类型：
--
作者：
E. Meyer;M. Georganopoulos
近年来，强大射电类星体的大规模喷流中的X射线发射机制一直是争论的焦点，有两种相互竞争的解释：或者X射线是同步加速器源，由与产生无线电-光学同步加速器分量的电子能量分布不同的电子能量分布产生，或者它们是由于宇宙微波背景光子（IC/CMB）被相对论电子在具有体洛伦兹因子Γ 10的强大相对论喷流中的逆康普顿散射。20.这两个模型意味着从根本上不同的条件下，在大规模的射流在射流速度，动能，和粒子加速机制的最大能量，具有重要意义的影响射流的大规模环境。关于X射线起源的大部分争论都集中在研究充分的3C 273源上。在这里，我们提出了费米的新观测结果，它对3C 273的大尺度喷流的伽马射线通量提出了上限，该上限在99.9%的置信度上违反了IC/CMB X射线模型通过外推结A的UV到X射线光谱而发现的预期通量，从而排除了IC/CMB对该源的解释。此外，费米给出的这个上限对多普勒聚束因子提出了一个限制，即假设场均分时，至少δ < 9;假设从节点A到D1的喷流没有大的减速，则可能低至δ < 5。
The X-ray emission mechanism in large-scale jets of powerful radio quasars has been a source of debate in recent years, with two competing interpretations: either the X-rays are of synchrotron origin, arising from a different electron energy distribution than that producing the radio to optical synchrotron component, or they are due to inverse Compton scattering of cosmic microwave background photons (IC/CMB) by relativistic electrons in a powerful relativistic jet with bulk Lorentz factor Γ ∼ 10–20. These two models imply radically different conditions in the large-scale jet in terms of jet speed, kinetic power, and maximum energy of the particle acceleration mechanism, with important implications for the impact of the jet on the large-scale environment. A large part of the X-ray origin debate has centered on the well-studied source 3C 273. Here we present new observations from Fermi which put an upper limit on the gamma-ray flux from the large-scale jet of 3C 273 that violates at a confidence greater that 99.9% the flux expected from the IC/CMB X-ray model found by extrapolation of the UV to X-ray spectrum of knot A, thus ruling out the IC/CMB interpretation entirely for this source when combined with previous work. Further, this upper limit from Fermi puts a limit on the Doppler beaming factor of at least δ < 9, assuming equipartition fields, and possibly as low as δ < 5, assuming no major deceleration of the jet from knots A through D1.