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arXiv 1504.02558astro-ph.SRastro-ph.IM
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恒星大气参数估计的SDSS/SEGUE谱特征分析

SDSS/SEGUE Spectral Feature Analysis For Stellar Atmospheric Parameter Estimation

Xiangru Li, Q. M. Jonathan Wu, Ali Luo, Yongheng Zhao, Yu Lu, Fang Zuo, Tan Yang, Yongjun Wang

备注：
22 pages, 10 figures, 15 table, ApJ
发表信息：
The Astrophysical Journal, 790 105 (2014)
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摘要：

大规模深空观测任务正在迅速收集大量的恒星光谱，这就需要直接从光谱中估计大气参数，并使在大数据集中对潜在原理进行统计研究成为可能。本文提出了一种从恒星光谱中估算参数$T_{eff}$、log $~g$和[Fe/H]的方法。利用这种技术，我们首先使用LASSO算法从恒星光谱中提取特征，然后使用SVR从提取的特征中估计参数。以SDSS/SEGUE Pipeline SSPP提供的参考参数为基础，在SDSS提供的20~000个恒星光谱子样本上，log $~T_{eff}$（$T_{eff}$为101.609921 K）、log $~g$和[Fe/H]的估计一致性分别为0.007458 dex、0.189557 dex和0.182060 dex，其中一致性用平均绝对误差来评价。该方案的突出特点是稀疏性、局部性和物理可解释性。在这项工作中，每个光谱由3821个通量组成，并分别检测了10个，19个和14个典型的波长位置，用于估计$T_{eff}$，log $~g$和[Fe/H]。结果表明，这些位置与恒星光谱的典型谱线有关。这一特性在研究分析结果的物理指示时很重要。然后，恒星光谱可以描述的个人流量的检测位置（PD）或本地积分流量附近（LI）。上述一致性是基于LI描述的特征的结果。如果用PD描述特征，log $~T_{eff}$的一致性为0.009092 dex（$T_{eff}$为124.545075 K），log $~g$为0.198928 dex，[Fe/H]为0.206814 dex。

英文摘要：

Large-scale and deep sky survey missions are rapidly collecting a large amount of stellar spectra, which necessitate the estimation of atmospheric parameters directly from spectra and makes it feasible to statistically investigate latent principles in a large dataset. We present a technique for estimating parameters $T_{eff}$, log$~g$ and [Fe/H] from stellar spectra. With this technique, we first extract features from stellar spectra using the LASSO algorithm; then, the parameters are estimated from the extracted features using the SVR. On a subsample of 20~000 stellar spectra from SDSS with reference parameters provided by SDSS/SEGUE Pipeline SSPP, estimation consistency are 0.007458 dex for log$~T_{eff}$ (101.609921 K for $T_{eff}$), 0.189557 dex for log$~g$ and 0.182060 for [Fe/H], where the consistency is evaluated by mean absolute error. Prominent characteristics of the proposed scheme are sparseness, locality, and physical interpretability. In this work, every spectrum consists of 3821 fluxes, and 10, 19, and 14 typical wavelength positions are detected respectively for estimating $T_{eff}$, log$~g$ and [Fe/H]. It is shown that the positions are related to typical lines of stellar spectra. This characteristic is important in investigating physical indications from analysis results. Then, stellar spectra can be described by the individual fluxes on the detected positions (PD) or local integration of fluxes near them (LI). The abovementioned consistency is the result based on features described by LI. If features are described by PD, consistency are 0.009092 dex for log$~T_{eff}$ (124.545075 K for $T_{eff}$), 0.198928 dex for log$~g$, and 0.206814 dex for [Fe/H].

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