本地旋涡星系的晕气体及其与气态卫星的关联
The Halo Gas of Local Spiral Galaxies and the Link to Gaseous Satellites
浏览论文内容
中文总结 AI 辅助
该研究选取21个本地旋涡星系样本，结合HST/COS数据探究其CGM与气态卫星的关联，发现气态卫星对宿主CGM的贡献较小，视线靠近大质量气态卫星时CGM探测率会升高。
中文摘要 AI 辅助
围绕大质量宿主星系运行的气态卫星会经历气体剥离，可能为宿主的星系际介质（CGM）提供额外气体。我们选取了21个距离小于15兆秒差距（Mpc）的本地旋涡星系样本，并利用现有的中性氢（HI）巡天数据表征其气态卫星种群，以探究宿主星系CGM与卫星气体含量之间的关联。我们的旋涡宿主星系中，大多数在其晕中拥有不超过3个气态卫星，这些卫星的中性氢质量（$M_{\rm HI}$）大于等于$10^7$倍太阳质量（$M_\u2609$）。利用26个哈勃空间望远镜（HST）的宇宙起源光谱仪（COS）类星体视线，其 impact 参数（ impact parameters）范围为0.1至0.9倍的$R_{\rm 200c}$（临界半径），我们发现红移$z\backsim0$的旋涡星系CGM在离子柱密度上表现出较大的内在散射（约1至2个数量级，dex），且其冷气体总质量为$2.5^{+7.5}_{\rm -1.9}\times10^9~(0.3Z_\u2609/Z')~M_\u2609$，与红移$z\backsim0.2$的同类天体（如COS-Halos）基本一致。按是否存在气态卫星对样本进行划分后，我们发现拥有气态卫星的宿主星系在金属离子吸收线（包括OI、AlII、CII、SiII、SiIII和SiIV）中的探测率更高，最高可达50%，这可能是因为它们的CGM金属丰度更高或冷相电离气体更多。然而，CGM柱密度与气态卫星的数量或其总中性氢质量均无显著相关性，这表明气态卫星对宿主CGM的贡献相较于CGM轮廓的内在散射可能很小，且轮廓趋势主要受视线与宿主的距离影响。当视线位于大质量气态卫星（质量相当于麦哲伦云或更高）的半维里半径以内时，CGM的探测率会升高，这可能是由于剥离的残骸所致。
英文摘要
Gaseous satellites orbiting massive host galaxies experience gas stripping and may contribute additional gas to the hosts' circumgalactic medium (CGM). We identify a sample of 21 local spiral galaxies ($<$15 Mpc) and characterize their gaseous satellite populations from existing HI surveys to investigate the connection between host galaxy CGM and satellite gas content. Most of our spiral hosts have $\leq3$ gaseous satellites in their halos with $M_{\rm HI}\gtrsim10^{7}~M_\odot$. Using 26 HST/COS QSO sightlines at impact parameters of 0.1--0.9 $R_{\rm 200c}$, we find that the CGM of $z\sim0$ spiral galaxies show large intrinsic scatters ($\sim1-2$ dex) in ion column densities and harbor a total cool gas mass of $2.5^{+7.5}_{\rm -1.9}\times10^9~(0.3Z_\odot/Z')~M_\odot$, largely consistent with their $z\sim0.2$ counterparts (e.g., COS-Halos). Splitting our sample by the presence of gaseous satellites, we find that galaxy hosts with gaseous satellites have higher detection rates (up to 50\%) in metal ion absorbers, including OI, AlII, CII, SiII, SiIII, and SiIV, possibly because their CGM is more metal enriched or has more ionized gas in the cool phase. However, the CGM column densities show no significant correlation with either the number of gaseous satellites or their total HI masses, suggesting that the contribution from the gaseous satellites to the host CGM is likely small compared to the intrinsic scatters in the CGM profiles, and the profile trends are mainly influenced by sightlines' proximity to the hosts. The CGM detection rate becomes elevated when a sightline is within half the virial radius of a massive gaseous satellite (LMC-like or higher mass), likely due to stripped debris.
发表机构
- Rensselaer Polytechnic Institute（伦斯勒理工学院）
- Columbia University（哥伦比亚大学）
- Tel Aviv University（特拉维夫大学）
- University of Washington（华盛顿大学）
机构由 AI 辅助整理，请以论文原文为准。
