The Most Predictive Physical Properties for the Stellar Population Radial Profiles of Nearby Galaxies
The Most Predictive Physical Properties for the Stellar Population Radial Profiles of Nearby Galaxies
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DOI：
10.3847/1538-4357/ab8cc2
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发表时间：
2020-04
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通讯作者：
Guangwen Chen;Hong-Xin Zhang;X. Kong;Zesen Lin;Zhixiong Liang;Xinkai Chen;Zuyi Chen;Zhiyuan Song-Zhiyua
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作者：
Guangwen Chen;Hong-Xin Zhang;X. Kong;Zesen Lin;Zhixiong Liang;Xinkai Chen;Zuyi Chen;Zhiyuan Song-Zhiyua
我们利用SDSS DR 15提供的MaNGA巡天的IFU光谱数据，对3654个邻近星系的D4000、光度加权恒星年龄τL和光度加权恒星金属丰度[Z/H]L（0.01 < z < 0.15）的径向分布进行了研究，试图探索中等恒星种群径向梯度（即，从1.5Re到1.5Re的星系质量（M_（10））、比星星形成率（sSFR）、形态和局部环境。我们发现，M ε是最具预测性的单一物理性质的EPD 4000和EPD 4000 [Z/H]L。最具预测性的特性是sSFR，在较小程度上是M τ L。环境参数，包括本地星系的超密度和中央卫星分裂，几乎没有相关性的恒星人口径向轮廓的整个样本，但恒星形成的卫星星系的M 1010 M 4000表现出显着的正相关性与星系的超密度。具有较低sSFR的星系平均具有更陡峭的负恒星人口梯度，并且对于更大质量的恒星形成星系，这种sSFR依赖性更强。中位星族梯度和M之间的负相关关系可以用分段关系来描述，因此log M 10.0的星系中位梯度（精确值取决于sSFR）的质量依赖性比M更高的星系要弱得多。虽然年龄和金属丰度的径向梯度对T型和中心恒星质量表面密度的依赖性通常不显着，但具有较晚T型或较低中心质量密度的星系往往具有显着较低的D4000，较年轻的τL和较低的[Z/H]L在本研究中探测的径向范围内。
We present a study on the radial profiles of the D4000, luminosity-weighted stellar ages τL, and luminosity-weighted stellar metallicities [Z/H]L of 3654 nearby galaxies (0.01 < z < 0.15) using the IFU spectroscopic data from the MaNGA survey available in the SDSS DR15, in an effort to explore the connection between median stellar population radial gradients (i.e., ∇D4000, ∇τL, ∇[Z/H]L) out to ∼1.5 Re and various galaxy properties, including stellar mass (M⋆), specific star formation rate (sSFR), morphologies, and local environment. We find that M⋆ is the single most predictive physical property for ∇D4000 and ∇[Z/H]L. The most predictive properties for ∇τL are sSFR and, to a lesser degree, M⋆. The environmental parameters, including local galaxy overdensities and central–satellite division, have virtually no correlation with stellar population radial profiles for the whole sample, but the ∇D4000 of star-forming satellite galaxies with M⋆ ≲ 1010 M⊙ exhibit a significant positive correlation with galaxy overdensities. Galaxies with lower sSFR have on average steeper negative stellar population gradients, and this sSFR dependence is stronger for more massive star-forming galaxies. The negative correlation between the median stellar population gradients and M⋆ are best described largely as segmented relationships, whereby median gradients of galaxies with log M⋆ ≲ 10.0 (with the exact value depending on sSFR) have much weaker mass dependence than galaxies with higher M⋆. While the dependence of the radial gradients of ages and metallicities on T-Types and central stellar mass surface densities are generally not significant, galaxies with later T-Types or lower central mass densities tend to have significantly lower D4000, younger τL, and lower [Z/H]L across the radial ranges probed in this study.