具有可变元素丰度比的Lick吸收线指数的通量校准恒星星族模型
Flux-calibrated stellar population models of Lick absorption-line indices with variable element abundance ratios
摘要：
我们提出了新的恒星星族模型的Lick吸收线指数与可变元素丰度比。该模型是基于我们的新的校准的吸收线指数与恒星参数来自英里恒星库。与我们以前的型号相比，关键的新颖之处在于它们现在可以提供更高的光谱分辨率MILES（~2.7A FWHM）和通量校准，因此不再依赖于Lick/IDS系统。这对于解释没有校准恒星的星系光谱是必不可少的，例如大型星系红移巡天或其他高红移观测。我们注意到，MILES分辨率似乎是可比的SDSS分辨率，使我们的模型可以应用于SDSS数据没有任何校正仪器光谱分辨率。我们第一次提供随机误差的模型预测的基础上的不确定性的校准功能和基本的恒星参数估计。我们表明，随机误差很小，除了在参数空间的边缘（高/低金属丰度和年轻的年龄<1 Gyr），恒星库是欠采样。我们用星系球状星团和星系梯度数据标定了年龄、金属丰度和α/Fe比等参数的基础模型。我们讨论了两个模型的味道不同的输入恒星的演化轨迹从弗拉斯卡蒂和帕多瓦集团。新的模型释放现在包括元素C、N、Mg、Na、Si、Ca、Ti、Cr和Fe的丰度变化。这些模型和舔吸特征标准集最容易获得的单个元素是C、N、Mg、Ca、Ti和Fe。模型数据可在www.icg.port.ac.uk/~thomasd上获得。
英文摘要：
We present new stellar population models of Lick absorption-line indices with variable element abundance ratios. The models are based on our new calibrations of absorption-line indices with stellar parameters derived from the MILES stellar library. The key novelty compared to our previous models is that they are now available at the higher spectral resolution of MILES (~2.7A FWHM) and flux-calibrated, hence not tied anymore to the Lick/IDS system. This is essential for the interpretation of galaxy spectra where calibration stars are not available, such as large galaxy redshift surveys or other high-redshift observations. We note that the MILES resolution appears to be comparable to SDSS resolution, so that our models can be applied to SDSS data without any corrections for instrumental spectral resolution. For the first time we provide random errors for the model predictions based on the uncertainties in the calibration functions and the underlying stellar parameter estimates. We show that random errors are small except at the edges of the parameter space (high/low metallicities and young ages <1 Gyr) where the stellar library is under-sampled. We calibrate the base model for the parameters age, metallicity and alpha/Fe ratio with galactic globular cluster and galaxy gradient data. We discuss two model flavours with different input stellar evolutionary tracks from the Frascati and Padova groups. The new model release now includes abundance variations of the elements C, N, Mg, Na, Si, Ca, Ti, Cr, and Fe. The individual elements that are best accessible with these models and the standard set of Lick absorption features are C, N, Mg, Ca, Ti, and Fe. The model data is available at www.icg.port.ac.uk/~thomasd.
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