论文标题
NGC 1313中年轻大型簇的化学丰度
Chemical abundances of Young Massive Clusters in NGC 1313
论文作者
论文摘要
我们分析了禁止的螺旋星系NGC 1313中五个年轻大型簇（YMC）的光谱观测，以从其综合光中获得详细的丰度。在非常大的望远镜（VLT）上使用X射击光谱仪观察到我们的YMC样本。我们利用理论等同源来生成合成的集成光谱，迭代单个元素丰度，直到与观测值最佳拟合为止。我们测量[CA/Fe]，[Ti/Fe]，[Mg/Fe]，[Cr/Fe]和[Ni/Fe]的丰度比。我们估计$ -0.124 $ \ pm $ 0.034 dex kpc $^{ - 1} $的Fe丰度梯度，以及$ - $ 0.093 $ \ $ 0.093 $ \ $ 0.009 dex kpc $^{ - 1} $的略浅的$α$梯度。这与以前集中在气相丰度上的金属性研究相反，后者发现NGC 1313是已知没有径向丰度梯度的最高质量块的星系。我们建议不同研究之间的梯度差异源自用于研究气相丰度的金属校准。我们还观察到了年龄金属性趋势，该趋势支持整个银河系中恒星形成的情况，并可能在YMC NGC 1313-379所在的西南地区恒星形成。
We analyze spectroscopic observations of five young massive clusters (YMCs) in the barred spiral galaxy NGC 1313 to obtain detailed abundances from their integrated light. Our sample of YMCs was observed with the X-Shooter spectrograph on the Very Large Telescope (VLT). We make use of theoretical isochrones to generate synthetic integrated-light spectra, iterating on the individual elemental abundances until converging on the best fit to the observations. We measure abundance ratios for [Ca/Fe], [Ti/Fe], [Mg/Fe], [Cr/Fe], and [Ni/Fe]. We estimate an Fe abundance gradient of $-$0.124 $\pm$ 0.034 dex kpc$^{-1}$, and a slightly shallower $α$ gradient of $-$0.093 $\pm$ 0.009 dex kpc$^{-1}$. This is in contrast to previous metallicity studies that focused on the gas-phase abundances, which have found NGC 1313 to be the highest-mass barred galaxy known not to have a radial abundance gradient. We propose that the gradient discrepancy between the different studies originates from the metallicity calibrations used to study the gas-phase abundances. We also observe an age-metallicity trend which supports a scenario of constant star formation throughout the galaxy, with a possible burst in star formation in the south-west region where YMC NGC 1313-379 is located.
