论文标题
金属和在遥远宇宙中寻找分子的搜索：在2 <z <3处对sub-dlas的麦克麦克（Magellan Mike）观察
Metals and a Search for Molecules in the Distant Universe: Magellan MIKE Observations of sub-DLAs at 2<z<3
论文作者
论文摘要
我们使用Mike SpectRograph上的观测值来限制了元素的化学和星形富集的化学富集和星星形成，我们介绍了从Z = 2.173到Z = 2.635的四个子dlas的元素Zn，S，O，C，Si和Fe的丰富度测量值。使用弱耗尽的元素O，S和或Zn，我们发现光电离校正后的金属度为[S/H] = -0.50 \ pm0.11，[O/H]，[O/H]> -0.84，[O/H] = -1.27 \ PM0.12，和[Zn/H] =+0.40 \ pm0.40 \ PM0.63 At At At AT分别为2.539和2.635。此外，我们能够使用两个子dlas的C II*和Si II*的细胞结构线对电子密度进行约束。我们发现，这些值远高于文献中DLA中的中值值。此外，我们估计在z = 2.173处的吸收剂的冷却速率LC = 1.20 \ times10-20-26 erg s-1，这表明该sub-dla中的恒星形成速率密度高于典型的恒星形成速率在相似的红移。我们还研究吸收器的金属性与速度分散关系。大多数吸收器都遵循了文献中sub-dla的质量与金属性关系所期望的趋势。最后，我们能够从各种强大的CO分子线的未检测到的分子柱密度限制。我们估计log n（co，j = 0）<13.87，log n（co，j = 0）<13.17和log n（co，j = 0）<13.08的3σupper限制，从CO AX 0-0，1-0，1-0频段的J = 0级别的非检测中的j = 0级别的吸收量中分别为1-0，和2-01544，1510和147.1510和147.1510和1478.
We present abundance measurements of the elements Zn, S, O, C, Si and Fe for four sub-DLAs at redshifts ranging from z=2.173 to z=2.635 using observations from the MIKE spectrograph on the Magellan telescope to constrain the chemical enrichment and star formation of gas-rich galaxies. Using weakly depleted elements O, S, and or Zn, we find the metallicities after the photoionization corrections to be [S/H]=-0.50\pm0.11, [O/H]>-0.84, [O/H]=-1.27\pm0.12, and [Zn/H]=+0.40\pm0.12 for the absorbers at z=2.173, 2.236, 2.539, and 2.635, respectively. Moreover, we are able to put constraints on the electron densities using the fine structure lines of C II* and Si II* for two of the sub-DLAs. We find that these values are much higher than the median values found in DLAs in the literature. Furthermore, we estimate the cooling rate lc=1.20\times10-26 erg s-1 per H atom for an absorber at z=2.173, suggesting higher star formation rate density in this sub-DLA than the typical star formation rate density for DLAs at similar redshifts. We also study the metallicity versus velocity dispersion relation for our absorbers. Most of the absorbers follow the trend one can expect from the mass versus metallicity relation for sub-DLAs in the literature. Finally, we are able to put limits on the molecular column density from the non detections of various strong lines of CO molecules. We estimate 3σupper limits of log N(CO,J=0)<13.87, log N(CO,J=0)<13.17, and log N(CO,J=0)<13.08, respectively, from the non-detections of absorption from the J=0 level in the CO AX 0-0, 1-0, and 2-0 bands near 1544, 1510, and 1478Å.
