论文标题
FRB 20121102a光谱中的传播效应
Propagation effects in the FRB 20121102A spectra
论文作者
论文摘要
我们推进了在快速无线电爆发（FRB）光谱中研究传播效应的理论方法。我们通过衍射透镜和强大的kolmogorov型闪烁来得出它们在模型中的自相关函数，并通过分析获得在不同的等离子体密度曲线上镜头的光谱。使用这些工具，我们将Gajjar等人的最高频率4-8 GHz数据重新分析。 （2018）对于重复的FRB 20121102a（FRB 121102）。在数据中，我们首先发现了几乎等距峰的显着光谱结构，分别为$ 95 \ pm 16 $ MHz。我们建议它可以源自质量$ 10^{ - 4} \，m_ \ odot $或在源附近的等离子不足上的质量$ 10^{ - 4} \质量$ 10^{ - 4} \的衍射镜头。其次，光谱包括不稳定的星际，大概是银河系闪烁。我们以参考频率6 GHz提取其去相关带宽$ 3.3 \ pm 0.6 $ MHz。第三个特征是GHz规模的模式，正如我们发现的那样，它随时间线性漂移，大概代表了宽带的传播效果，例如GHz规模的闪烁。第四，许多光谱在7.1 GHz处的狭窄峰支配。我们建议它可能是由于在宿主星系中通过等离子体镜头的传播引起的。第五，分开传播效应，我们给出了强烈的论点，即内在的祖细胞光谱具有狭窄的GHz带宽和可变的中心频率。这证实了先前观察结果的期望。我们讨论上述光谱特征的替代解释。
We advance theoretical methods for studying propagation effects in the Fast Radio Burst (FRB) spectra. We derive their autocorrelation function in the model with diffractive lensing and strong Kolmogorov-type scintillations and analytically obtain the spectra lensed on different plasma density profiles. With these tools, we reanalyze the highest frequency 4-8 GHz data of Gajjar et al. (2018) for the repeating FRB 20121102A (FRB 121102). In the data we discover, first, a remarkable spectral structure of almost equidistant peaks separated by $95\pm 16$ MHz. We suggest that it can originate from diffractive lensing of the FRB signals on a compact gravitating object of mass $10^{-4}\, M_\odot$ or on a plasma underdensity near the source. Second, the spectra include erratic interstellar, presumably Milky Way scintillations. We extract their decorrelation bandwidth $3.3\pm 0.6$ MHz at reference frequency 6 GHz. The third feature is a GHz-scale pattern which, as we find, linearly drifts with time and presumably represents a wide-band propagation effect, e.g. GHz-scale scintillations. Fourth, many spectra are dominated by a narrow peak at 7.1 GHz. We suggest that it can be caused by a propagation through a plasma lens, e.g., in the host galaxy. Fifth, separating the propagation effects, we give strong arguments that the intrinsic progenitor spectrum has narrow GHz bandwidth and variable central frequency. This confirms expectations from the previous observations. We discuss alternative interpretations of the above spectral features.
