CHAOS. VII. A Large-scale Direct Abundance Study in M33
CHAOS. VII. A Large-scale Direct Abundance Study in M33
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DOI：
10.3847/1538-4357/ac947d
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发表时间：
2022-09
期刊：
影响因子：
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通讯作者：
N. Rogers;E. Skillman;R. Pogge;D. Berg;K. Croxall;Jo Bartlett;K. Arellano-Córdova;J. Moustakas
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文献类型：
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作者：
N. Rogers;E. Skillman;R. Pogge;D. Berg;K. Croxall;Jo Bartlett;K. Arellano-Córdova;J. Moustakas
化学丰度的分散对驱动星系化学富集的过程提供了非常强的约束。由于螺旋星系M33的距离很近，它一直是许多化学丰度调查的焦点，以研究大空间尺度上的化学丰度富集和分散。螺旋星系的化学丰度项目用大双筒望远镜（LBT）观测了M33中的100个H ii区域，产生了该星系中最大的电子温度（Te）和直接丰度的均匀样本。我们的LBT观测产生了一个稳健的氧丰度梯度为− 0.037 ± 0.007 dex kpc − 1，并表明相对于该梯度，氧丰度的固有分散性相对较小（0.043 ± 0.015 dex）。N/H和N/O的分散度同样很小，Ne、S、Cl和Ar相对于O的丰度与α过程或依赖α过程的元素的太阳比一致。总之，M33中的ISM是化学上混合良好的，并且从内到外均匀富集，没有证据表明在星系的给定半径内存在显着的丰度变化。我们的研究结果进行了比较，在文献中的众多研究，我们讨论了可能的污染源，可以膨胀丰度分散测量。重要的是，如果丰度是从一个单一的T e测量和T e-T e的关系是依赖于推断未测量的电离区的温度，这可能会导致系统的偏差，增加测量的分散高达0.11德克斯。
The dispersion in chemical abundances provides a very strong constraint on the processes that drive the chemical enrichment of galaxies. Due to its proximity, the spiral galaxy M33 has been the focus of numerous chemical abundance surveys to study the chemical enrichment and dispersion in abundances over large spatial scales. The CHemical Abundances Of Spirals project has observed ∼100 H ii regions in M33 with the Large Binocular Telescope (LBT), producing the largest homogeneous sample of electron temperatures (T e ) and direct abundances in this galaxy. Our LBT observations produce a robust oxygen abundance gradient of −0.037 ± 0.007 dex kpc−1 and indicate a relatively small (0.043 ± 0.015 dex) intrinsic dispersion in oxygen abundance relative to this gradient. The dispersions in N/H and N/O are similarly small, and the abundances of Ne, S, Cl, and Ar relative to O are consistent with the solar ratio as expected for α-process or α-process-dependent elements. Taken together, the ISM in M33 is chemically well-mixed and homogeneously enriched from inside out, with no evidence of significant abundance variations at a given radius in the galaxy. Our results are compared to those of the numerous studies in the literature, and we discuss possible contaminating sources that can inflate abundance dispersion measurements. Importantly, if abundances are derived from a single T e measurement and T e –T e relationships are relied on for inferring the temperature in the unmeasured ionization zone, this can lead to systematic biases that increase the measured dispersion up to 0.11 dex.