论文标题
Yonsei进化人群合成（YEP）模型。 iii。正常和氦气的简单恒星种群的表面亮度波动
Yonsei Evolutionary Population Synthesis (YEPS) Model. III. Surface Brightness Fluctuation of Normal and Helium-enhanced Simple Stellar Populations
论文作者
论文摘要
我们提出了一个正常和富含简单的恒星种群（SSP）的表面亮度波动（SBF）的进化人群合成模型。尽管我们针对正常人群的SBF模型与其他现有模型一致，但与正常人群相比，HE-HE-HE-HE人群包含更热的水平分支恒星和更明亮的红色紧身恒星，这需要SSPS的SBF发生重大变化。我们表明，即使以$ i $的价格，SBF的幅度也会受到富裕人群的影响至少$ \ sim $ 0.3〜mag，并且以给定颜色的近级频段，经常从中得出基于SBF的距离。然而，由于观测和模型中的不确定性，银河球状簇和早期型星系的SBF不允许验证富集的模型。 We propose that when combined with independent metallicity and age indicators such as ${\rm Mg}_2$ and ${\rm H}β$, the UV and optical SBFs can readily detect underlying He-rich populations in unresolved stellar systems at a distance out to $\gtrsim 20$\,Mpc.可以从http://cosmic.yonse.ac.kr/yeps.htm下载一组SSP的SSP的光谱光度法和SBF数据。
We present an evolutionary population synthesis model of the surface brightness fluctuation (SBF) for normal and He-enriched simple stellar populations (SSPs). While our SBF model for the normal-He population agrees with other existing models, the He-rich population, containing hotter horizontal-branch stars and brighter red-clump stars than the normal-He population, entails a substantial change in the SBF of SSPs. We show that the SBF magnitudes are affected by He-rich populations at least $\sim$0.3~mag even in $I$- and near-IR bands at given colors, from which the SBF-based distances are often derived. Due to uncertainties both in observations and models, however, the SBFs of Galactic globular clusters and early-type galaxies do not allow verifying the He-enriched model. We propose that when combined with independent metallicity and age indicators such as ${\rm Mg}_2$ and ${\rm H}β$, the UV and optical SBFs can readily detect underlying He-rich populations in unresolved stellar systems at a distance out to $\gtrsim 20$\,Mpc. A full set of the spectro-photometric and SBF data for SSPs from the Yonsei Evolutionary Population Synthesis (YEPS) model is available for download at http://cosmic.yonsei.ac.kr/YEPS.htm.
