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arXiv 1010.3846astro-ph.CO
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超亮红外星系Spitzer IRS光谱的主成分分析

Principal component analysis of the Spitzer IRS spectra of ultraluminous infrared galaxies

Lingyu Wang, Duncan Farrah, Brian Connolly, Natalia Connolly, Vianney LeBouteiller, Seb Oliver, Henrik Spoon

摘要:

本文对119个z<0.35的局部超亮红外星系的Spitzer红外光谱进行了第一主成分分析。本研究的目的是客观和唯一的本地ULIRG人口使用所观察到的光谱中包含的所有信息。我们从数据集的协方差矩阵中推导出前三个主成分(PC),它们占方差的90%以上。第一个PC的特点是粉尘温度和源和粉尘混合物的几何形状。第二个PC是一个纯粹的恒星形成组件。第三个PC代表了恒星形成活动和活动星系核上升之间的反相关。使用前三个PC,我们能够准确地重建样品中的大部分光谱。我们的工作表明,有几个因素是重要的,在表征的ULIRG人口,尘埃温度,几何形状,恒星形成强度,活动星系的贡献等,我们还比较PCA和其他诊断,如6.2微米的PAH发射功能的9.7微米的硅酸盐吸收深度和其他观测值,如光谱类型的比率。

英文摘要:

We present the first principal component analysis (PCA) applied to a sample of 119 Spitzer Infrared Spectrograph (IRS) spectra of local ultraluminous infrared galaxies (ULIRGs) at z<0.35. The purpose of this study is to objectively and uniquely characterise the local ULIRG population using all information contained in the observed spectra. We have derived the first three principal components (PCs) from the covariance matrix of our dataset which account for over 90% of the variance. The first PC is characterised by dust temperatures and the geometry of the mix of source and dust. The second PC is a pure star formation component. The third PC represents an anti-correlation between star formation activity and a rising AGN. Using the first three PCs, we are able to accurately reconstruct most of the spectra in our sample. Our work shows that there are several factors that are important in characterising the ULIRG population, dust temperature, geometry, star formation intensity, AGN contribution, etc. We also make comparison between PCA and other diagnostics such as ratio of the 6.2 microns PAH emission feature to the 9.7 micron silicate absorption depth and other observables such as optical spectral type.

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。

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