论文标题
H II区域深光谱的C,N,O,NE,S,Cl和AR的银河径向丰度梯度
The Galactic radial abundance gradients of C, N, O, Ne, S, Cl and Ar from deep spectra of H II regions
论文作者
论文摘要
我们使用从文献中收集的33 h II区域的深光谱进行了银河系的C,N,O,NE,S,CL和AR的径向丰度梯度的重新评估,涵盖了6至17 kpc的半乳房距离。对象的距离已使用Gaia视差修改。我们使用更新的原子数据以均匀的方式重新计算物理条件和离子丰度。所有对象都有直接确定电子温度,从而允许其确切的离子丰度。我们分析和比较每个元素的不同ICF方案,以获得最自信的总丰度。由于修改后的距离,我们的结果不支持先前关于内部银河磁盘中O/H梯度可能扁平的主张。我们发现银河N/O梯度相当平坦,与其他螺旋星系中发现的相反。某些元素的梯度的斜率对所使用的ICF方案敏感,尤其是在NE的情况下。 C,N,O,S,Cl和AR梯度周围的分散体是确定丰度的典型不确定性顺序,这意味着ISM离子化气相的化学成分中没有明显的不均匀性。我们发现log(s/o)和日志(Cl/o)的平坦梯度以及对数(ne/o)和log(ar/o)的非常浅或扁平的梯度,与O。
We present a reassessment of the radial abundance gradients of C, N, O, Ne, S, Cl and Ar in the Milky Way using deep spectra of 33 H II regions gathered from the literature, covering Galactocentric distances from 6 to 17 kpc. The distances of the objects have been revised using Gaia parallaxes. We recalculate the physical conditions and ionic abundances in an homogeneous way using updated atomic data. All the objects have direct determination of the electron temperature, permitting to derive their precise ionic abundances. We analyze and compare different ICF schemes for each element in order to obtain the most confident total abundances. Due to the revised distances, our results do not support previous claims about a possible flattening of the O/H gradient in the inner Galactic disk. We find that the Galactic N/O gradient is rather flat, in contrast to what has been found in other spiral galaxies. The slope of the gradients of some elements is sensitive to the ICF scheme used, especially in the case of Ne. The dispersion around the fit for the gradients of C, N, O, S, Cl and Ar is of the order of the typical uncertainties in the determination of the abundances, implying the absence of significant inhomogeneities in the chemical composition of the ionized gas phase of the ISM. We find flat gradients of log(S/O) and log(Cl/O) and very shallow or flat ones for log(Ne/O) and log(Ar/O), consistent with a lockstep evolution of Ne, S, Cl and Ar with respect to O.