利用壳层的PCA分解进行恒星活动校正
Stellar activity correction using PCA decomposition of shells
摘要：
上下文恒星活动和仪器信号是使用径向速度（RV）技术探测类地行星的主要限制。最近的研究表明，减轻这些扰动影响的关键可能在于分析光谱本身，而不是RV时间序列和一些活动代理。目标。本文的目标是证明，我们可以达到进一步提高RV精度通过执行主成分分析（PCA）分解的壳时间序列，与壳作为投影的频谱到spaceplumalised通量与通量梯度。方法.通过执行壳时间序列的PCA分解，可以获得与开普勒运动无关的一阶谱变化的基础。然后，与该基础相关联的时间系数可以用于校正RV中的非多普勒特征。结果我们将这种新方法应用于HD 10700和HD 128621的YARARA后处理光谱时间序列。在HD 10700上，我们证明，由于行星信号注入，这种新的方法可以成功地解开真正的多普勒信号从仪器系统学。对HD 128621的应用表明，在恒星自转周期和一年的假频中观察到的强恒星活动信号在周期图分析中变得微不足道。五年数据的RV均方根从2.44 m/s降至1.73 m/s。这种新方法使我们能够强烈地减轻恒星活动，然而，噪声注入测试表明，需要相当高的信噪比（S/N>250），以纠正观察到的活动信号HD 128621。
英文摘要：
Context. Stellar activity and instrumental signals are the main limitations to the detection of Earth-like planets using the radial velocity (RV) technique. Recent studies show that the key to mitigating those perturbing effects might reside in analysing the spectra themselves, rather than the RV time series and a few activity proxies. Aims. The goal of this paper is to demonstrate that we can reach further improvement in RV precision by performing a principal component analysis (PCA) decomposition of the shell time series, with the shell as the projection of a spectrum onto the spacenormalised flux versus flux gradient. Methods. By performing a PCA decomposition of shell time series, it is possible to obtain a basis of first-order spectral variations that are not related to Keplerian motion. The time coeffcients associated with this basis can then be used to correct for non-Dopplerian signatures in RVs. Results. We applied this new method on the YARARA post-processed spectra time series of HD10700 and HD128621. On HD10700, we demonstrate, thanks to planetary signal injections, that this new approach can successfully disentangle real Dopplerian signals from instrumental systematics. The application of this new methodology on HD128621 shows that the strong stellar activity signal seen at the stellar rotational period and one-year aliases becomes insignificant in a periodogram analysis. The RV root mean square on the five-year data is reduced from 2.44 m/s down to 1.73 m/s. This new approach allows us to strongly mitigate stellar activity, however, noise injections tests indicate that rather high signal-to-noise ratio (S/N>250) is required to correct for the observed activity signal on HD128621.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
