An X-Ray Imaging Survey of Quasar Jets: The Complete Survey
An X-Ray Imaging Survey of Quasar Jets: The Complete Survey
复制标题
DOI：
10.3847/1538-4357/aaaf66
复制
发表时间：
2018-02
期刊：
影响因子：
--
通讯作者：
H. Marshall;J. Gelbord;D. Worrall;M. Birkinshaw;D. Schwartz;D. Jauncey;G. Griffiths;D. Murphy
中科院分区：
文献类型：
--
作者：
H. Marshall;J. Gelbord;D. Worrall;M. Birkinshaw;D. Schwartz;D. Jauncey;G. Griffiths;D. Murphy
我们提出了钱德拉X射线成像的通量有限的样品的平谱射电类星体与喷状结构。X射线从56个喷射器中的59%被检测到。没有发现反向喷射。核心光谱符合光子指数为Γx的幂律谱，其分布符合正态分布，平均值为1.61+0.04−0.05，色散为0.15+0.04−0.03。结果表明，X射线和射电波段喷流之间的光谱指数α δ的分布符合高斯分布，平均值为0.974 ± 0.012，色散为0.077 ± 0.008。我们测试的模型，其中千秒差距尺度的X射线从逆康普顿散射宇宙微波背景光子的喷气的相对论性电子（IC-CMB模型）。在IC-CMB模型中，由观测到的通量和发射区的表观大小计算出的Q与红移的关系为（1 + z）3+α。我们拟合了Q α（1 + z）a，发现a = 0.88 ± 0.90，并在99.5%置信度下拒绝了平均α β以IC-CMB模型中预期的方式依赖于红移的假设。这一结论是减轻了缺乏详细的知识的发射区的几何形状，这需要更深或更高分辨率的X射线观测。此外，如果IC-CMB模型对千秒差距尺度喷流的X射线辐射是有效的，那么喷流必须平均减速：在千秒差距和千秒差距尺度之间，整体洛伦兹因子应该从大约15下降到2-3。我们的研究结果复合的问题，IC-CMB模型在解释的X射线发射的千帕级喷流。
We present Chandra X-ray imaging of a flux-limited sample of flat spectrum radio-emitting quasars with jet-like structure. X-rays are detected from 59% of 56 jets. No counter-jets were detected. The core spectra are fitted by power-law spectra with a photon index Γx, whose distribution is consistent with a normal distribution, with a mean of 1.61+0.04−0.05 and dispersion of 0.15+0.04−0.03. We show that the distribution of αrx, the spectral index between the X-ray and radio band jet fluxes, fits a Gaussian with a mean of 0.974 ± 0.012 and dispersion of 0.077 ± 0.008. We test the model in which kiloparsec-scale X-rays result from inverse Compton scattering of cosmic microwave background photons off the jet’s relativistic electrons (the IC-CMB model). In the IC-CMB model, a quantity Q computed from observed fluxes and the apparent size of the emission region depends on redshift as (1 + z)3+α. We fit Q ∝ (1 + z)a, finding a = 0.88 ± 0.90, and reject at 99.5% confidence the hypothesis that the average αrx depends on redshift in the manner expected in the IC-CMB model. This conclusion is mitigated by a lack of detailed knowledge of the emission region geometry, which requires deeper or higher resolution X-ray observations. Furthermore, if the IC-CMB model is valid for X-ray emission from kiloparsec-scale jets, then the jets must decelerate on average: bulk Lorentz factors should drop from about 15 to 2–3 between parsec and kiloparsec scales. Our results compound the problems that the IC-CMB model has in explaining the X-ray emission of kiloparsec-scale jets.