利用强线方法的两种不同实现：经验R校准和基于贝叶斯模型的{ \sc HII-CHI-mistry}（{ \sc HCm}）程序，计算了来自MaNGA DR 15巡天的1431个星系的氧丰度（O/H）、氮氧丰度（N/O）及其相应的径向梯度。我们发现，这两种丰度计算方法揭示了O/H梯度和星系的恒星质量之间的相关性。这种关系是非线性的，在中等质量范围内的平均梯度最陡，而在高质量和低质量星系中的平均梯度较平坦。平均而言，N/O梯度和恒星质量之间的关系是非线性的，在中等质量范围（$\log(M/M_\sun) \sim 10$）的梯度最陡，高质量星系的梯度较平坦，低质量星系的梯度最平坦。然而，在以前的研究中报道的更高质量的N/O梯度变陡的总趋势仍然很明显。我们发现O/H和N/O梯度与由$D$（4000）指数追踪的星系平均恒星年龄之间存在依赖关系。对于较低质量的星系，两个梯度通常在$D$（4000）的中间值时较陡，而在$D$（4000）的低值和高值时较平坦。只有最大的星系才不表现出这种相关性。我们将这种行为解释为金属丰度梯度随恒星星族年龄的演化。虽然与具有负的$D$（4000）梯度的星系相比，具有正的$D$（4000）径向梯度斜率的星系倾向于具有更平坦的O/H和N/O梯度。
英文摘要：
We derive the oxygen abundance (O/H), the nitrogen-to-oxygen (N/O) abundance ratio, and their corresponding radial gradients for a sample of 1431 galaxies from MaNGA DR15 survey using two different realizations of the strong line method: empirical R calibration and the Bayesian model-based {\sc HII-CHI-mistry} ({\sc HCm}) code. We find that both abundance calculation methods reveal a correlation between the O/H gradient and the stellar mass of a galaxy. This relation is non-linear, with the steepest average gradients in the intermediate mass range and flatter average gradients for high- and low-mass galaxies. The relation between the N/O gradient and the stellar mass is, on average, non-linear with the steepest gradients in the intermediate mass range ($\log(M/M_\sun) \sim 10$), flatter gradients for high-mass galaxies, and the flattest gradients for low-mass galaxies. However, the general trend of steepening N/O gradient for higher masses, reported in previous studies, remains evident. We find a dependence between the O/H and N/O gradients and the galaxy mean stellar age traced by the $D$(4000) index. For galaxies of lower masses, both gradients are, generally, steeper for intermediate values of $D$(4000) and flatter for low and high values of $D$(4000). Only the most massive galaxies do not show this correlation. We interpret this behaviour as an evolution of the metallicity gradients with the age of stellar population. Though the galaxies with a positive slope of the $D$(4000) radial gradient tend to have a flatter O/H and N/O gradients, as compared to those with a negative $D$(4000) gradient.
Adsorption energies of carbon, nitrogen, and oxygen atoms on the low-temperature amorphous water ice: A systematic estimation from quantum chemistry calculations
Modeling Nitrogen Fractionation in the Protoplanetary Disk around TW Hya: Model Constraints on Grain Population and Carbon-to-Oxygen Elemental Abundance Ratio
Influence of the Void Environment on Chemical Abundances in Dwarf Galaxies and Implications for Connecting Star Formation and Halo Mass
我们研究如何空洞环境影响星系的化学演化，通过比较的氧和氮的丰度的矮星系的空洞与矮星系在密集的地区。利用SDSS DR 7的光谱观测，我们估计了889个空矮星系和672个矮星系在致密区域的氧，氮，氖丰度。一个替代的[OII] 3727的双重发展，允许SDSS矮星系的氧丰度估计在所有的红移与直接Te方法。我们发现，空矮星系有大约相同的氧丰度和Ne/O比，略高的氖丰度，略低的氮丰度和N/O比比在致密的环境中的矮星系。我们的结论是，空洞环境有轻微的影响矮星系的化学演化。我们的质量N/O关系表明，氮的二次生产开始在一个较低的恒星质量在空矮星系比矮星系在密集的环境。我们的矮星系样本显示了sSFR和N/O比之间的强烈反相关性，提供了证据表明，氧是在质量更高的恒星中产生的，而不是合成氮的恒星。较低的N/O比和较小的恒星质量的二次氮生产中看到的空矮星系可能表明延迟的恒星形成和宇宙缩小的大尺度环境的依赖。在空洞矮星系中，氧丰度向稍高的方向转变，这可能是空洞中暗物质晕质量与恒星质量之比大于致密区域的证据。
Exploring the Milky Way stellar disk. Carbon, nitrogen, oxygen, sulphur, potassium, and copper abundances for 714 F- and G-type dwarf stars in the solar neighbourhood
