发表机构
University of California, Santa Cruz; Johns Hopkins University; Arizona State University; Raman Research Institute; University of California Observatories; San Diego State University; University of California, San Diego（加州大学圣克鲁兹分校; 约翰斯·霍普金斯大学; 亚利桑那州立大学; 拉曼研究所; 加州大学观测站; 圣地亚哥州立大学; 加州大学圣迭戈分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用MaNGA数据比较静止星系中Na I D和Ca II H&K吸收线，发现Ca II气体储库更大更广，且受尘埃屏蔽影响小，两者共同示踪可更全面揭示星系气体流动。
AI 中文摘要
二十多年来，Na I D（λ5891.58, 5897.56 Å）吸收线一直是星系中冷中性气体的主要光学示踪剂。相比之下，Ca II H&K（λ3934.78, 3969.59 Å）吸收线既能示踪中性气体也能示踪电离气体，但对其研究相对较少。在此，我们利用MaNGA积分场单元光谱仪对140个红色间歇星系（局域静止星系，拥有低光度活动星系核和双对称电离外流）以及140个静止星系的对照样本进行了空间分辨观测，对Na I D和Ca II H&K星际吸收线进行了比较研究。通过对Na I D和Ca II K谱线进行高斯拟合，我们测量了气体速度和速度弥散。我们发现，Ca II气体储库的面积比Na I D大至约6倍，径向延伸范围是其两倍，线宽比Na I D宽约1.7-1.8倍。此外，Na I D显示出对尘埃储库大小的直接依赖性，但Ca II的这种相关性消失。在仅有约20%的星系中，Na I D探测范围超出尘埃区域，而Ca II的这一比例跃升至约70%。基于这些发现，我们认为尘埃在保护Na I D免受电离辐射方面起着重要作用，而Ca II由于其更高的电离势，对屏蔽的依赖性较小，更容易在尘埃区域之外存活。Na I D和Ca II示踪了不同的气体成分，同时研究两者可以更全面地描绘星系中的气体流动。
英文摘要
For over two decades, Na I D ($λ\lambda5891.58, 5897.56$ Å) absorption has been the primary optical tracer of cool, neutral gas in galaxies. In contrast, Ca II H&K ($λλ$3934.78, 3969.59 Å), which traces both neutral and ionized gas, has been comparatively unexplored. Here, we present a comparative study of the Na I D and Ca II H&K interstellar absorption lines using spatially resolved MaNGA IFU spectroscopy of 140 red geyser galaxies (local quiescent systems hosting low-luminosity AGN with bisymmetric ionized outflows) and a control sample of 140 quiescent galaxies. Using Gaussian fits to the Na I D and Ca II K lines, we measure gas velocity and dispersion. We find that the Ca II reservoirs are up to ~ 6 times larger in area, twice as radially extended, and have ~ 1.7 - 1.8x broader line widths than Na I D. Furthermore, Na I D shows a direct dependence on dust reservoir size, but the correlation vanishes for Ca II. In only ~ 20% of galaxies do the Na I D detections extend beyond dust regions, but this fraction jumps to ~70% for Ca II. Using these findings, we argue that dust plays a significant role in shielding Na I D from ionizing radiation, whereas Ca II, with its higher ionization potential, is not as dependent on shielding and can more easily survive beyond regions of dust. Na I D and Ca II trace distinct gas components, and studying both together provides a more complete picture of gas flows in galaxies.
Comments23 pages, 19 figures; submitted to ApJ
