Breaking the degeneracy between gas inflow and outflows with stellar metallicity: insights on M 101
Breaking the degeneracy between gas inflow and outflows with stellar metallicity: insights on M 101
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DOI：
10.1093/mnras/stab147
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发表时间：
2021-01
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影响因子：
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通讯作者：
X. Kang;R. Chang;R. Kudritzki;X. Gong;Fenghui Zhang
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文献类型：
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作者：
X. Kang;R. Chang;R. Kudritzki;X. Gong;Fenghui Zhang
建立了一个分析化学演化模型，研究了恒星形成星系的气相和恒星金属丰度的径向分布。利用该模型，可以由恒星与气体的质量比得到恒星的气相和金属丰度。气体的流入和流出过程对最终的气相金属丰度都起着重要的作用，恒星形成星系的气体流入和流出速率之间存在着简并效应。另一方面，恒星金属丰度对气体流出速率比对气体流入速率更敏感，这有助于打破恒星形成星系的参数简并。我们将这种分析方法应用于邻近盘星系M101，并采用经典的χ2方法来探讨模型参数对金属丰度结果的影响。可以发现，气相和恒星金属丰度的组合确实是更有效地限制气体流入和流出速率。我们的结果还表明，具有相对较强的气体流出但较弱的气体流入的模型相当好地描述了M101的演化。
An analytical chemical evolution model is constructed to investigate the radial distribution of gas-phase and stellar metallicity for star-forming galaxies. By means of the model, the gas-phase and stellar metallicity can be obtained from the stellar-to-gas mass ratio. Both the gas inflow and outflow processes play an important role in building the final gas-phase metallicity, and there exists degeneracy effect between the gas inflow and outflow rates for star-forming galaxies. On the other hand, stellar metallicity is more sensitive to the gas outflow rate than to the gas inflow rate, and this helps to break the parameter degeneracy for star-forming galaxies. We apply this analysis method to the nearby disc galaxy M 101 and adopting the classical χ2 methodology to explore the influence of model parameters on the resulted metallicity. It can be found that the combination of gas-phase and stellar metallicity is indeed more effective for constraining the gas inflow and outflow rates. Our results also show that the model with relatively strong gas outflows but weak gas inflow describes the evolution of M 101 reasonably well.