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arXiv 0809.4491astro-ph
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表面亮度起伏:概率和统计基础I:恒星星族和理论SBF

On surface brightness fluctuations: probabilistic and statistical bases I: Stellar population and theoretical SBF

M. Cervino, V. Luridiana, L. Jamet

摘要:

这项工作的目的是提供一个理论公式的表面亮度波动(SBF)的概率合成模型的框架内,并区分不同的分布参与SBF的定义。研究结果:我们提出了三种SBF的定义:(i)恒星星族SBF,它可以从综合模型中计算出来,并为恒星星族研究提供了一个内在的拟合度量;(ii)理论SBF,它包括恒星星族SBF加上一个附加项,该附加项考虑了每个分辨率元素的恒星数分布psi(N);在psi(N)被假设为泊松分布的非常特殊的情况下,理论SBF与Tennis & Schneider(1998)的定义一致。然而,泊松贡献理论的SBF是约0.1%的贡献,由于恒星星族SBF,所以没有理由包括任何参考泊松统计的SBF定义;(iii)观测SBF,这是那些获得的观测分布在理论SBF。最后,我们展示了计算SBF的替代方法,并将恒星星族SBF的应用扩展到定义标准恒星星族研究的拟合度量。结论:我们证明,SBF是一个概率范式的人口合成,其中积分亮度有一个内在的分布性质的观测证据,他们排除了通常假设的确定性范式的恒星星族建模。

英文摘要:

This work aims to provide a theoretical formulation of Surface Brightness Fluctuations (SBF) in the framework of probabilistic synthesis models, and to distinguish between the different distributions involved in the SBF definition. RESULTS: We propose three definitions of SBF: (i) stellar population SBF, which can be computed from synthesis models and provide an intrinsic metric of fit for stellar population studies; (ii) theoretical SBF, which include the stellar population SBF plus an additional term that takes into account the distribution of the number of stars per resolution element psi(N); theoretical SBF coincide with Tonry & Schneider (1998) definition in the very particular case that psi(N) is assumed to be a Poisson distribution. However, the Poisson contribution to theoretical SBF is around 0.1% of the contribution due to the stellar population SBF, so there is no justification to include any reference to Poisson statistics in the SBF definition; (iii) observational SBF, which are those obtained in observations that are distributed around the theoretical SBF. Finally, we show alternative ways to compute SBF and extend the application of stellar population SBF to defining a metric of fitting for standard stellar population studies. CONCLUSIONS: We demostrate that SBF are observational evidence of a probabilistic paradigm in population synthesis, where integrated luminosities have an intrinsic distributed nature, and they rule out the commonly assumed deterministic paradigm of stellar population modeling.

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