论文标题
使用恒星种群模型重建Z〜2处观察到的电离光子生产效率
Reconstructing the observed ionizing photon production efficiency at z~2 using stellar population models
论文作者
论文摘要
电离光子生产效率$ξ_{ion} $是一个关键参数，可为早期宇宙的性质提供许多物理约束，包括星系对宇宙及时完成的及时完成的贡献。在这里，我们使用Keck/Mosfire和Zfourge多波段光度数据来探索带有$ z \ sim2 $的$ξ_{ion} $带有$ log_ {10}（m _*/m_*/m_ \ odot）\ sim9.0-11.5 $。我们的130 \ halpha \检测显示中位数$ log_ {10}（ξ_{ion} [hz/erg]）$ $ 24.8 \ pm0.5 $，当使用Calzetti等人纠正灰尘。 （2000）尘埃处方。我们的值是选择$ξ_{ion} $值的质量/大小的典型代表。使用Bassv2.2.1和Starburst99具有简单参数恒星形成历史的恒星种群模型（SFH），我们发现，即使使用二进制/恒星旋转的恒星进化的效果，也以$ log_ {10}（10}}（ξ_{Ion} $ equive y low hz/erg years）$ 25. 0.0 $ 25. 0.00 $ 25. 0.00; （ew）和红色与我们观察到的$ z \ sim2 $相比。 We find that introducing star-bursts to the SFHs resolve the tension with the models, however, due to the rapid time evolution of $ξ_{ion}$, H$α$ EWs, and rest-frame optical colors, our Monte Carlo simulations of star-bursts show that random distribution of star-bursts in evolutionary time of galaxies are unlikely to explain the observed distribution.因此，我们观察到的样品是根据其过去的SFH特别选择的，或者是恒星模型需要的其他机制来重现观察到的高星系的高紫外线光度，以给定的氢电离光子的给定生产速率。
The ionizing photon production efficiency, $ξ_{ion}$, is a critical parameter that provides a number of physical constraints to the nature of the early Universe, including the contribution of galaxies to the timely completion of the reionization of the Universe. Here we use KECK/MOSFIRE and ZFOURGE multi-band photometric data to explore the $ξ_{ion}$ of a population of galaxies at $z\sim2$ with $log_{10}(M_*/M_\odot)\sim9.0-11.5$. Our 130 \Halpha\ detections show a median $log_{10}(ξ_{ion}[Hz/erg])$ of $24.8\pm0.5$ when dust corrected using a Calzetti et al. (2000) dust prescription. Our values are typical of mass/magnitude selected $ξ_{ion}$ values observed in the $z\sim2$ Universe. Using BPASSv2.2.1 and Starburst99 stellar population models with simple parametric star-formation-histories (SFH), we find that even with models that account for effects of stellar evolution with binaries/stellar rotation, model galaxies at $log_{10}(ξ_{ion}[Hz/erg])\lesssim25.0$ have low H$α$ equivalent widths (EW) and redder colors compared to our $z\sim2$ observed sample. We find that introducing star-bursts to the SFHs resolve the tension with the models, however, due to the rapid time evolution of $ξ_{ion}$, H$α$ EWs, and rest-frame optical colors, our Monte Carlo simulations of star-bursts show that random distribution of star-bursts in evolutionary time of galaxies are unlikely to explain the observed distribution. Thus, either our observed sample is specially selected based on their past SFH or stellar models require additional mechanisms to reproduce the observed high UV luminosity of galaxies for a given production rate of hydrogen ionizing photons.
