论文标题

多面膜最小二乘反向卷积:使用量身定制的口罩提取RVS

Multi-Mask Least-Squares Deconvolution: Extracting RVs using tailored masks

论文作者

Lienhard, F., Mortier, A., Buchhave, L., Cameron, A. Collier, Lopez-Morales, M., Sozzetti, A., Watson, C. A., Cosentino, R.

论文摘要

为了推动径向速度(RV)系外行星检测阈值,找到更可靠的径向速度提取方法至关重要。在过去的二十年中,最小二乘反卷积(LSD)技术已被用于从光谱学数据中推断出恒星的磁通量。它依赖于恒星吸收系相似的假设。尽管此假设很简单,但LSD为强度光谱提供了一个良好的模型,同样是其多普勒转移的估计值。我们介绍了多面膜最小二乘反向卷积(MM-LSD)RV提取管道,该管道在连续归一化和介留吸收线校正后使用LSD从二维梯形阶顺序中提取径向速度。 LSD的灵活性允许随意排除光谱线或像素,提供了一种排除受仪器问题影响的可变线或像素的方法。 MM-LSD管道对太阳的HARPS-N数据进行了测试,并选择了5.7 <VMAG <12.6的良好观察到的恒星。对于中位信噪比100以上的FGK型恒星,与基于互相关函数技术的HARPS-N RV提取管道相比,该管道的RV时间序列平均分别降低了12%。 MM-LSD管道可用作独立的RV代码,也可以修改并扩展以提取磁场强度的代理。

To push the radial velocity (RV) exoplanet detection threshold, it is crucial to find more reliable radial velocity extraction methods. The Least-Squares Deconvolution (LSD) technique has been used to infer the stellar magnetic flux from spectropolarimetric data for the past two decades. It relies on the assumption that stellar absorption lines are similar in shape. Although this assumption is simplistic, LSD provides a good model for intensity spectra and likewise an estimate for their Doppler shift. We present the Multi-Mask Least-Squares Deconvolution (MM-LSD) RV extraction pipeline which extracts the radial velocity from two-dimensional echelle-order spectra using LSD with multiple tailored masks after continuum normalisation and telluric absorption line correction. The flexibility of LSD allows to exclude spectral lines or pixels at will, providing a means to exclude variable lines or pixels affected by instrumental problems. The MM-LSD pipeline was tested on HARPS-N data for the Sun and selected well-observed stars with 5.7 < Vmag < 12.6. For FGK-type stars with median signal-to-noise above 100, the pipeline delivered RV time series with on average 12 per cent lower scatter as compared to the HARPS-N RV extraction pipeline based on the Cross-Correlation Function technique. The MM-LSD pipeline may be used as a standalone RV code, or modified and extended to extract a proxy for the magnetic field strength.

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