标题： M31北部刺状结构中的行星状星云的光谱观测 显示英文标题

标题： Spectroscopic Observations of Planetary Nebulae in the Northern Spur of M31

摘要： 我们利用帕洛马天文台5.1米海尔望远镜上的双摄谱仪获得了仙女座星系（M31）北方脊上三个行星状星云（PNe）的光谱。样本选自Merrett等人所做的观测。我们的目的是使用PNe作为化学丰度示踪物来研究M31子结构的形成。[O III] 4363高激发线在两个天体的光谱中被探测到，使得温度测定成为可能。离子丰度从碰撞电离激发线推导，氮、氧、氖以及硫和氩的元素丰度也被估算出来。通过使用本样本以及文献中的M31盘面和核球PNe，研究了氧与α-元素丰度比之间的相关性。在这三个PNe之一中，我们观察到相对于在相似星系中心距下的M31盘面样本，氧丰度相对较高。至少这三个北方脊PNe中的一个的结果可能与M31北方脊提出的可能起源一致，即北方脊与南方流相连，并且这两个子结构构成了M31卫星星系的潮汐碎片。 显示英文摘要

摘要： We present spectroscopy of three planetary nebulae (PNe) in the Northern Spur of the Andromeda Galaxy (M31) obtained with the Double Spectrograph on the 5.1 m Hale Telescope at the Palomar Observatory. The samples are selected from the observations of Merrett et al. Our purpose is to investigate formation of the substructures of M31 using PNe as a tracer of chemical abundances. The [O III] 4363 auroral line is detected in the spectra of two objects, enabling temperature determinations. Ionic abundances are derived from the observed collisionally excited lines, and elemental abundances of nitrogen, oxygen, and neon as well as sulphur and argon are estimated. Correlations between oxygen and the alpha-element abundance ratios are studied, using our sample and the M31 disk and bulge PNe from the literature. In one of the three PNe, we observed relatively higher oxygen abundance compared to the disk sample in M31 at similar galactocentric distances. The results of at least one of the three Northern Spur PNe might be in line with the proposed possible origin of the Northern Spur substructure of M31, i.e. the Northern Spur is connected to the Southern Stream and both substructures comprise the tidal debris of the satellite galaxies of M31.