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arXiv 1603.03037astro-ph.GA
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用BEAGLE模拟和解释星系的光谱能量分布

Modelling and interpreting spectral energy distributions of galaxies with BEAGLE

Jacopo Chevallard, Stéphane Charlot

摘要:

我们提出了一个新一代的工具来模拟和解释星系的光谱能量分布(SED),它以一致的方式结合了辐射的产生及其通过星际和星系间介质的传输。这个灵活的工具,名为BEAGLE(Bayesian Analysis of GalaxyssEds),允许人们建立模拟星系目录,并根据物理参数解释光度和光谱星系观测的任何组合。该工具的当前版本包括对恒星和光电离气体发射、尘埃衰减的多功能建模,并考虑到不同的仪器效应,如光谱通量校准和线扩散函数。我们展示了第一个应用程序的小猎犬工具的解释宽带SED的${\sim}10^4$星系在红移$0.1 \lesssim z\lesssim8$公布的样本。我们发现,使用这个多用途的工具上的光度红移导出的约束是可比的使用公共的,专用的光度红移代码和量化的结果在一个严格的统计方式。我们还展示了如何使用Python扩展PYP-BEAGLE对BEAGLE输出数据进行后处理,以表征模型和观测之间的系统偏差,特别是通过后验预测检查。BEAGLE工具的模块化设计允许容易的扩展,例如,包括中性星系和环星系气体的吸收,以及活动星系核、尘埃和激波电离气体的发射。关于BEAGLE工具的公开发布的信息将在http://www.jacopochevallard.org/beagle上维护。

英文摘要:

We present a new-generation tool to model and interpret spectral energy distributions (SEDs) of galaxies, which incorporates in a consistent way the production of radiation and its transfer through the interstellar and intergalactic media. This flexible tool, named BEAGLE (for BayEsian Analysis of GaLaxy sEds), allows one to build mock galaxy catalogues as well as to interpret any combination of photometric and spectroscopic galaxy observations in terms of physical parameters. The current version of the tool includes versatile modeling of the emission from stars and photoionized gas, attenuation by dust and accounting for different instrumental effects, such as spectroscopic flux calibration and line spread function. We show a first application of the BEAGLE tool to the interpretation of broadband SEDs of a published sample of ${\sim}10^4$ galaxies at redshifts $0.1 \lesssim z\lesssim8$. We find that the constraints derived on photometric redshifts using this multi-purpose tool are comparable to those obtained using public, dedicated photometric-redshift codes and quantify this result in a rigorous statistical way. We also show how the post-processing of BEAGLE output data with the Python extension PYP-BEAGLE allows the characterization of systematic deviations between models and observations, in particular through posterior predictive checks. The modular design of the BEAGLE tool allows easy extensions to incorporate, for example, the absorption by neutral galactic and circumgalactic gas, and the emission from an active galactic nucleus, dust and shock-ionized gas. Information about public releases of the BEAGLE tool will be maintained on http://www.jacopochevallard.org/beagle.

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