论文标题
在太阳能频谱中颗粒的签名，如CO $^5 $ BOLD所示
The signature of granulation in a solar power spectrum as seen with CO$^5$BOLD
论文作者
论文摘要
在太阳能振荡器的功率谱中看到的颗粒背景对提取有关恒星振荡的精确和详细信息提出了一个严重的挑战。我们使用用Co $^5 $ BOLD计算的太阳的3D流体动力学模拟，我们研究了使用贝叶斯方法来推断的各种背景模型，该模型可以在模拟功率谱中最适合对背景的最佳拟合。我们发现，最佳拟合是由表达式提供的，包括总体功率水平和两个特征频率，一个指数为2，一个具有自由指数的指数约为6。我们评估了3D水合代码对此结果的影响，通过使用Stagger进行模拟并发现主要结论是没有变节的。但是，两种代码之间最佳拟合的细节略有不同，但是我们通过研究空间分辨率的影响以及模拟对拟合的持续时间来解释这种差异。此外，我们研究将白噪声添加到模拟时间序列的影响，这是模仿真实恒星的简单方法。我们发现，只要噪声水平不太低，结果就与无噪声情况一致。
The granulation background seen in the power spectrum of a solar-like oscillator poses a serious challenge for extracting precise and detailed information about the stellar oscillations. Using a 3D hydrodynamical simulation of the Sun computed with CO$^5$BOLD, we investigate various background models to infer, using a Bayesian methodology, which one provides the best fit to the background in the simulated power spectrum. We find that the best fit is provided by an expression including the overall power level and two characteristic frequencies, one with an exponent of 2 and one with a free exponent taking on a value around 6. We assess the impact of the 3D hydro-code on this result by repeating the analysis with a simulation from Stagger and find that the main conclusion is unchanged. However, the details of the resulting best fits differ slightly between the two codes, but we explain this difference by studying the effect of the spatial resolution and the duration of the simulation on the fit. Additionally, we look into the impact of adding white noise to the simulated time series as a simple way to mimic a real star. We find that, as long as the noise level is not too low, the results are consistent with the no-noise case.
