AI 中文总结
本研究通过交叉匹配星表与巡天数据构建超扩散星系（UDG）和低表面亮度（LSB）星系的HI探测与未探测样本，分析其标度关系等特性，支持UDG存在多种形成路径。
AI 中文摘要
通过将SMUDGes星表与FASHI和ALFALFA氢 I（HI）巡天交叉匹配，我们构建了包含112个超扩散星系（UDG）和48个低表面亮度（LSB）星系的HI探测样本，首次为76个星系提供了基于HI的红移。利用DESI DR1红移，我们组装了包含168个星系的HI未探测样本用于堆叠分析，在恒星质量低于10^{8.5} M☉的两个恒星质量区间中获得了探测结果。结合光学、紫外和HI数据，我们研究了恒星质量、恒星形成率、气体分数和运动学特性。我们对UDG和LSB星系的HI质量-光学大小关系进行了系统分析，结果显示这两类星系遵循与正常星系相似的质量-光学大小标度关系，在假设光学大小可表征HI分布范围的前提下，暗示其具有平均HI表面密度。它们的恒星质量-大小关系表明，对于中心表面亮度μ_{0,g}≥24mag arcsec^{-2}的星系，恒星表面密度几乎恒定，与UDG或LSB的分类无关。许多UDG和LSB星系在给定速度下，相对于重子塔利-费希尔关系系统性地向更高重子质量偏移，这与已解析HI运动学的UDG中发现的趋势一致。两类星系均表现出低恒星形成效率和长气体耗散时间，支持UDG存在多种形成路径。
英文摘要
By cross-matching the SMUDGes catalog with the FASHI and ALFALFA HI surveys, we construct an HI-detected sample of 112 ultra-diffuse galaxies (UDGs) and 48 low-surface-brightness (LSB) galaxies, providing HI-based redshifts for 76 galaxies for the first time. Using DESI DR1 redshifts, we assemble an HI-non-detected sample of 168 galaxies for stacking analysis, with detections in two stellar mass bins below 10^{8.5} M_sun. Combining optical, UV, and HI data, we investigate stellar masses, star formation rates, gas fractions, and kinematics. We present a systematic analysis of the HI mass--optical size relation for UDGs and LSBs, showing both populations follow a mass--optical size scaling similar to normal galaxies, suggesting an average HI surface density, under the assumption that the optical size traces the extent of the HI distribution. Their stellar mass--size relation indicates nearly constant stellar surface densities for galaxies with central surface brightness mu_{0,g}>~24mag arcsec^{-2}, independent of UDG or LSB classification. Many UDGs and LSB galaxies are systematically offset from the baryonic Tully--Fisher relation toward higher baryonic masses at a given velocity, consistent with trends found in UDGs with resolved HI kinematics. Both populations exhibit low star formation efficiencies and long gas depletion times, supporting multiple formation pathways for UDGs.
CommentsAccepted for publication in The Astrophysical Journal; 25 pages, 10 figures
