发表机构
European Southern Observatory; Centre for Astrophysics and Supercomputing, Swinburne University of Technology; CSIRO Space & Astronomy; CNRS; Max-Planck-Institut für extraterrestrische Physik; Stockholm University; Kavli Institute for Cosmology, University of Cambridge; Cavendish Laboratory, University of Cambridge（欧洲南方天文台; 斯威本科技大学天体物理与超级计算中心; CSIRO空间与天文学部; 法国国家科学研究中心; 马克斯·普朗克地外物理研究所; 斯德哥尔摩大学; 剑桥大学卡弗里宇宙学研究所; 剑桥大学卡文迪许实验室）
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MUSE-ALMA晕族样本普查z~0.5 HI吸收选择星系中的凝聚重子，发现分子气体比例随恒星质量下降更陡，高恒星面密度星系重子比例最高，并提供多尺度多相气体视图以探测重子预算。
AI 中文摘要
我们利用MUSE-ALMA晕族样本对凝聚重子（恒星和冷气体）进行普查，以研究多相星际介质和星系周介质（CGM）。该样本包含79个富气体星系，红移范围0.2<z<1.2，位于类星体视线附近强HI莱曼-α吸收体附近，投影间距约5-270千秒差距，径向速度间隔最高达500公里/秒。HST光谱表征吸收体，而HST成像、MUSE和ALMA观测追踪恒星、电离气体和分子气体。我们得到以下结果。（i）由光学性质推断的HI质量与碰撞参数<100千秒差距时由CGM吸收体性质推导的HI质量大体一致，尽管星系群环境可能显著影响这些估计。（ii）分子气体比例随恒星质量的下降比HI比例更陡。这表明恒星形成比冷气体储备增长更快，而大质量星系要么更有效地消耗其分子气体，要么将HI转化为H2的效率较低。（iii）具有高恒星面密度的星系表现出最高的重子比例。这可能反映了重子反馈，其在高面密度系统中可产生更平坦的内部暗物质轮廓，或孔径效应，其中电离气体运动学示踪物仅探测致密源中最内部、重子主导的区域，但在具有扩展重子分布的源中延伸更深入暗物质晕。（iv）少数星系与JWST探测到的低质量z~6星系的重子主导后裔一致，而许多星系似乎是更暗物质主导、较低质量系统，其前身超出JWST探测极限。这项研究提供了星系内外气体的多尺度、多相视图，使我们能够探测宇宙时间尺度上的重子预算。
英文摘要
We use the MUSE-ALMA Haloes sample to build a census of the condensed baryons (stars and cold gas) to study the multiphase interstellar medium and circumgalactic medium (CGM). The sample includes 79 gas-rich galaxies at 0.2<z<1.2 located near strong HI Ly-alpha absorbers along quasar sightlines within projected separations of ~5-270 kpc and radial velocity separations of up to 500 km/s. HST spectroscopy characterises the absorbers, while HST imaging, MUSE and ALMA observations trace the stars, ionised gas and molecular gas. We find the following results. (i) HI masses inferred from optical properties show broad agreement with those derived from the CGM absorber properties for impact parameters <100 kpc, although group environments can significantly influence these estimates. (ii) The molecular gas fraction declines more steeply with stellar mass than the HI fraction. This suggests that stars build up more rapidly than the cold gas reservoir, while massive galaxies either consume their molecular gas more efficiently or convert HI into H2 less efficiently. (iii) Galaxies with high stellar surface densities exhibit the highest baryon fractions. This may reflect baryonic feedback, which can produce flatter inner dark matter profiles in high surface density systems, or aperture effects, where the ionised gas kinematic tracer probes only the innermost, baryon-dominated regions in compact sources, but extends further into the dark matter halo in sources with extended baryonic distributions. (iv) A few galaxies are consistent with being the baryon-dominated descendants of the low mass z~6 galaxies detected by JWST, while many appear to be substantially more dark matter dominated, lower mass systems with progenitors beyond JWST detection limits. This study provides a multiscale, multiphase view of the gas in and around galaxies, allowing us to probe the baryon budget across cosmic time.
CommentsAccepted for publication in A&A. 14 pages, 7 Figures (and appendices). Part of the MUSE-ALMA survey series, see simultaneously posted papers by Barfety et al. and Péroux et al
