标题： 邻近强引力透镜吸收线系统的吸收线与发射线丰度比较：SBS 1543+593研究 显示英文标题

标题： A Comparison of Absorption and Emission Line Abundances in the Nearby Damped Lyman-alpha Galaxy SBS 1543+593

摘要： 我们利用哈勃空间望远镜（HST）上的太空望远镜成像光谱仪（STIS）测量了附近强氢吸收线（DLA）星系SBS 1543+593星际介质（ISM）中的硫丰度[S/H] = -0.41 ± 0.06。 一方面，这一类星体吸收线丰度与另一方面从发射线诊断得到的HII区丰度之间的直接比较得出相同的结果：中性ISM中的硫丰度与距离3千秒差距之外HII区中测得的氧丰度非常一致。 我们的结果与其它近期研究的结果形成对比，那些研究声称HI（吸收）和HII（发射）区域的丰度存在数量级差异。 我们还推导出镍丰度[Ni/H] < -0.81，约为硫丰度的三分之一，并建议这种缺失可能是由于尘埃，尽管我们不能排除α元素过量作为较低金属丰度的原因。 如果一些SII产生于电离气体中，则我们的[S/H]测量值可能被高估；根据沿视线方向该星系的一个合理恒星形成率以及从SBS 1543+593检测到的CII* 1335.7吸收线测量值，我们确定金属丰度不可能比我们推导的值小超过0.25 dex。 我们估计冷中性介质的冷却速率log [l_c (ergs s^{-1} H atom^{-1})] = -27.0，与高红移DLA样本中观测到的值相同。 显示英文摘要

摘要： We have used the Space Telescope Imaging Spectrograph (STIS) aboard HST to measure a sulfur abundance of [S/H] = -0.41 +/-0.06 in the interstellar medium (ISM) of the nearby damped Lyman-alpha (DLA) absorbing galaxy SBS 1543+593. A direct comparison between this QSO absorption line abundance on the one hand, and abundances measured from HII region emission line diagnostics on the other, yield the same result: the abundance of sulfur in the neutral ISM is in good agreement with that of oxygen measured in an HII region 3 kpc away. Our result contrasts with those of other recent studies which have claimed order-of-magnitude differences between HI (absorption) and HII (emission) region abundances. We also derive a nickel abundance of [Ni/H] < -0.81, some three times less than that of sulfur, and suggest that the depletion is due to dust, although we cannot rule out an over-abundance of alpha-elements as the cause of the lower metallicity. It is possible that our measure of [S/H] is over-estimated if some SII arises in ionized gas; adopting a plausible star formation rate for the galaxy along the line of sight, and a measurement of the CII* 1335.7 absorption line detected from SBS 1543+593, we determine that the metallicity is unlikely to be smaller than we derive by more than 0.25 dex. We estimate that the cooling rate of the cool neutral medium is log [l_c (ergs s^{-1} H atom^{-1})] = -27.0, the same value as that seen in the high redshift DLA population.