NGC 628的PPAK宽场积分场光谱：II。发射谱线丰度分析
PPAK Wide-field Integral Field Spectroscopy of NGC 628: II. Emission line abundance analysis
摘要：
在该系列的第二篇论文中，我们介绍了NGC 628的二维（2D）发射线丰度分析，NGC 628是PPAK积分场光谱（IFS）附近Galerkin Survey：PINGS中最大的天体。我们介绍的方法应用于2D IFS数据，以提取和处理大的光谱样本，从2D丰度分析可以稍后进行。我们获得最完整和可靠的丰度梯度的星系最新的，通过使用最大数量的光谱点采样的星系，并通过比较不同的强线金属丰度指标的统计意义。我们发现以前没有报道过的功能，这个星系，这意味着一个多模态的丰度梯度一致的一个几乎平坦的分布在星系的最里面的区域，沿光盘和浅梯度或接近恒定的金属丰度超出星系的光学边缘的陡峭的负梯度。N/O比似乎遵循相同的径向行为。我们表明，所观察到的金属丰度的分散显示没有系统的空间位置，信号噪声或电离条件的依赖性，这意味着在一个给定的半径的散射丰度反映了真正的空间物理变化的氧含量。此外，通过利用2D IFS数据，我们能够构建星系的2D金属丰度结构，检测金属增强区域，并显示它们根据金属丰度估计器的选择而变化。对NGC 628圆盘轴对称变化的分析表明，星系不同对称区域的物理条件和恒星形成历史以不同的方式演化。
英文摘要：
In this second paper of the series, we present the 2-dimensional (2D) emission line abundance analysis of NGC 628, the largest object within the PPAK Integral Field Spectroscopy (IFS) Nearby Galaxies Survey: PINGS. We introduce the methodology applied to the 2D IFS data in order to extract and deal with large spectral samples, from which a 2D abundance analysis can be later performed. We obtain the most complete and reliable abundance gradient of the galaxy up-to-date, by using the largest number of spectroscopic points sampled in the galaxy, and by comparing the statistical significance of different strong-line metallicity indicators. We find features not previously reported for this galaxy that imply a multi-modality of the abundance gradient consistent with a nearly flat-distribution in the innermost regions of the galaxy, a steep negative gradient along the disc and a shallow gradient or nearly-constant metallicity beyond the optical edge of the galaxy. The N/O ratio seems to follow the same radial behaviour. We demonstrate that the observed dispersion in metallicity shows no systematic dependence with the spatial position, signal-to-noise or ionization conditions, implying that the scatter in abundance for a given radius is reflecting a true spatial physical variation of the oxygen content. Furthermore, by exploiting the 2D IFS data, we were able to construct the 2D metallicity structure of the galaxy, detecting regions of metal enhancement, and showing that they vary depending on the choice of the metallicity estimator. The analysis of axisymmetric variations in the disc of NGC 628 suggest that the physical conditions and the star formation history of different-symmetric regions of the galaxy have evolved in a different manner.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
