LINEARLY SUPPORTING FEATURE EXTRACTION FOR AUTOMATED ESTIMATION OF STELLAR ATMOSPHERIC PARAMETERS
LINEARLY SUPPORTING FEATURE EXTRACTION FOR AUTOMATED ESTIMATION OF STELLAR ATMOSPHERIC PARAMETERS
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DOI：
10.1088/0067-0049/218/1/3
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发表时间：
2015-04
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通讯作者：
Xiangru Li;Yu Lu;G. Comte;A. Luo;Yongheng Zhao;Yongjun Wang
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作者：
Xiangru Li;Yu Lu;G. Comte;A. Luo;Yongheng Zhao;Yongjun Wang
我们描述了一种从恒星光谱中提取线性支持特征的方案，以自动估计大气参数T𝚎𝚏𝚏？>；，logg和[Fe/H]。“线性支持”是指通过线性模型从提取的特征中准确地估计大气参数。该方法首先利用小波包对光谱进行分解，并将其表示为分解系数，然后利用最小绝对收缩和选择算子(LARS)bs从分解系数中提取具有代表性的光谱特征，最后利用线性回归方法从检测到的特征中估计大气参数T𝚎𝚏𝚏？该方案的一个突出特点是，它能够定量评估每个探测到的特征对大气参数估计的贡献，并能够追溯该特征的物理意义。这项工作还表明，组件的有用性取决于波长和频率。所提出的方案已经在来自斯隆数字天空测量(SDSS)/SEGUE的真实光谱和根据Kurucz的NEWODF模型计算的合成光谱上进行了评估。在实谱上，我们提取了23个特征来估计T𝚎𝚏𝚏？>；，62个特征用于估计logg，68个特征用于估计[Fe/H]。我们的估计与SDSS光谱参数管道提供的结果的检验一致性表明，LOG T𝚎𝚏𝚏和gt；的平均绝对误差(MAE)为0.0062 dex(T𝚎𝚏𝚏和gt；的平均绝对误差为83K)，logg的平均绝对误差为0.2345 dex，[Fe/H]的平均绝对误差为0.1564 dex。对于合成光谱，MAE测试精度：LOG T𝚎𝚏𝚏？>；为0.0022 dex(T𝚎𝚏𝚏？>；为32 K)，log为0.0337 dex，[Fe/H]为0.0268 dex。
We describe a scheme to extract linearly supporting (LSU) features from stellar spectra to automatically estimate the atmospheric parameters T 𝚎𝚏𝚏 ?> , log g, and [Fe/H]. “Linearly supporting” means that the atmospheric parameters can be accurately estimated from the extracted features through a linear model. The successive steps of the process are as follow: first, decompose the spectrum using a wavelet packet (WP) and represent it by the derived decomposition coefficients; second, detect representative spectral features from the decomposition coefficients using the proposed method Least Absolute Shrinkage and Selection Operator (LARS)bs; third, estimate the atmospheric parameters T 𝚎𝚏𝚏 ?> , log g, and [Fe/H] from the detected features using a linear regression method. One prominent characteristic of this scheme is its ability to evaluate quantitatively the contribution of each detected feature to the atmospheric parameter estimate and also to trace back the physical significance of that feature. This work also shows that the usefulness of a component depends on both the wavelength and frequency. The proposed scheme has been evaluated on both real spectra from the Sloan Digital Sky Survey (SDSS)/SEGUE and synthetic spectra calculated from Kurucz's NEWODF models. On real spectra, we extracted 23 features to estimate T 𝚎𝚏𝚏 ?> , 62 features for log g, and 68 features for [Fe/H]. Test consistencies between our estimates and those provided by the Spectroscopic Parameter Pipeline of SDSS show that the mean absolute errors (MAEs) are 0.0062 dex for log T 𝚎𝚏𝚏 ?> (83 K for T 𝚎𝚏𝚏 ?> ), 0.2345 dex for log g, and 0.1564 dex for [Fe/H]. For the synthetic spectra, the MAE test accuracies are 0.0022 dex for log T 𝚎𝚏𝚏 ?> (32 K for T 𝚎𝚏𝚏 ?> ), 0.0337 dex for log g, and 0.0268 dex for [Fe/H].