论文标题
使用新定义的高分辨率指数
Non-solar abundance ratios trends of dEs in Fornax Cluster using newly defined high resolution indices
论文作者
论文摘要
我们使用一组新定义的线指数在大规模的Fornax矮星系样本中对恒星种群进行了详细研究。使用来自积分现场光谱数据的数据，我们研究了八个DES的丰度比，恒星质量从10 $^8 $到10 $^{9.5} $^{9.5} $ M $ _ \ odot $在Fornax群集中。我们介绍了一组新的高分辨率舔式指数的定义，用于未解决的小型恒星系统的出色种群研究。我们确定了23个吸收特征和连续区域，主要由12个元素（NA，CA，SC，Ti，V，Cr，Mn，Mn，Fe，Ni，ni，y，ba和nd）在4700-5400Å的波长范围内主导，并将它们表征为年龄，金属性和Alpha元素丰度比率的函数。我们分析了八个DES，并解释了在新的高分辨率指数系统中测量的线强度，并借助具有足够高的光谱分辨率的恒星种群模型。我们获得了许多以前从未研究过本地组以外的椭圆形的元素的丰度比率。这些代理代表了基础恒星种群模型的预测指数强度相对偏差，该模型按照银河系的丰度模式构建。将丰度代理趋势结果与本地组分辨率恒星的丰度比和较大早期型星系的综合光的指数进行了比较。我们发现，我们所有的矮人都表现出与银河系磁盘一致的丰度比例，这表明与高质量对应物相比，形成缓慢。
We perform a detailed study of the stellar populations in a sample of massive Fornax dwarf galaxies using a set of newly defined line indices. Using data from the Integral field spectroscopic data, we study abundance ratios of eight dEs with stellar mass ranging from 10$^8$ to 10$^{9.5}$ M$_\odot$ in the Fornax cluster. We present the definitions of a new set of high-resolution Lick-style indices to be used for stellar population studies of unresolved small stellar systems. We identify 23 absorption features and continuum regions, mainly dominated by 12 elements (Na, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Y, Ba and Nd) in the wavelength range 4700 - 5400 Å and characterise them as a function of age, metallicity and alpha element abundance ratios. We analyse eight dEs and interpret the line strengths, measured in our new high resolution system of indices, with the aid of stellar population models with high enough spectral resolution. We obtain abundance ratio proxies for a number of elements that have never been studied before for dwarf ellipticals outside the Local Group. These proxies represent relative deviations from predicted index-strengths of base stellar population models built-up following the abundance pattern of The Galaxy. The abundance proxy trend results are compared to abundance ratios from resolved stars in the Local Group, and indices from integrated light of larger early-type galaxies. We find that all our dwarfs show a pattern of abundance ratios consistent with the disk of the Milky Way, indicative of slow formation in comparison to their high mass counterparts.
