The stellar evolution of Luminous Red Galaxies, and its dependence on colour, redshift, luminosity and modelling
The stellar evolution of Luminous Red Galaxies, and its dependence on colour, redshift, luminosity and modelling
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发光红色星系的恒星演化及其对颜色、红移、光度和建模的依赖
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发表时间：
2010
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通讯作者：
R. Jimenez
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作者：
R. Tojeiro;W. Percival;A. Heavens;R. Jimenez
我们在斯隆数字巡天(SDSS)的第七次光谱数据发布中提出了一系列发光红色星系(LRG)的颜色演化模型，使用全谱拟合程序VESPA计算了高信噪比叠加光谱。颜色演化模型是作为颜色、光度和红移的函数来计算的，我们没有先验地假设LRG根据恒星演化构成统一的星系群。通过根据化石记录计算恒星形成历史，测量到的星系恒星演化与调查的选择函数分离，后者也随着红移而演变。我们给出了用三种不同的恒星种群合成(SPS)程序计算的演化模型。我们证明了LRG纯被动恒星演化的传统基准模型是基本正确的，但它不足以解释全光谱特征。我们还发现，对该模型的高阶修正依赖于所使用的SPS，特别是在计算最近恒星形成的数量时。在某些情况下，年轻恒星的数量可能是不可忽略的，并且对于解释选择框内LRG的数密度作为红移的函数具有重要意义。然而，尘埃消光比SPS模型更可靠：消光随着光度的降低、红移的增加和r−I颜色的增加而增加。我们将在http://www.icg.port.ac.uk/~tojeiror/lrg_evolution/.上公开提供颜色演变轨迹
We present a series of colour-evolution models for luminous red galaxies (LRGs) in the seventh spectroscopic data release of the Sloan Digital Sky Survey (SDSS), computed using the full-spectrum fitting code vespa on high signal-to-noise ratio stacked spectra. The colour-evolution models are computed as a function of colour, luminosity and redshift, and we do not a priori assume that LRGs constitute a uniform population of galaxies in terms of stellar evolution. By computing star formation histories from the fossil record, the measured stellar evolution of the galaxies is decoupled from the survey’s selection function, which also evolves with redshift. We present these evolutionary models computed using three different sets of stellar population synthesis (SPS) codes. We show that the traditional fiducial model of purely passive stellar evolution of LRGs is broadly correct, but it is not sufficient to explain the full-spectral signature. We also find that higher-order corrections to this model are dependent on the SPS used, particularly when calculating the amount of recent star formation. The amount of young stars can be non-negligible in some cases, and has important implications for the interpretation of the number density of LRGs within the selection box as a function of redshift. Dust extinction, however, is more robust to the SPS modelling: extinction increases with decreasing luminosity, increasing redshift and increasing r − i colour. We are making the colour-evolution tracks publicly available at http://www.icg.port.ac.uk/~tojeiror/lrg_evolution/.