发表机构
Aix Marseille Univ, CNRS, CNES, LAM; Department of Physics & Astronomy, University College London; Max-Planck-Institut für Radioastronomie; Institute for Astronomy, University of Edinburgh; Lawrence Berkeley National Laboratory; Department of Physics, Boston University; Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano; INAF-Osservatorio Astronomico di Brera; Departamento de Astrofísica, Universidad de La Laguna (ULL); Instituto de Astrofísica de Canarias（艾克斯马赛大学; 伦敦大学学院物理与天文系; 马克斯·普朗克射电天文研究所; 爱丁堡大学天体物理研究所; 劳伦斯伯克利国家实验室; 波士顿大学物理系; 米兰大学阿尔多·蓬特莫利物理系; 意大利国家天体物理研究所布雷拉天文台; 拉帕拉大学天体物理学系; 加那利天体物理学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究基于DESI DR2的约6000个恒星形成星系，分析中性气体流与恒星形成主序、质量-金属丰度关系的关联，揭示不同流速的气体流对恒星形成率和金属丰度的影响，明确中性气体流与星系标度关系偏移的关联。
AI 中文摘要
气体的流入与流出调控着星系的成长，但已测量的气体流与星系标度关系之间的直接观测关联仍然有限。利用DESI DR2中约6000个具有同轴Na I D吸收线的恒星形成星系，我们研究了检测到中性气体流入和流出的星系系统在恒星形成主序（SFMS）和质量-金属丰度关系（MZR）中的分布情况。我们将流入和流出宿主星系与恒星质量、红移匹配的对照星系，以及从未检测到气体流的星系得到的SFMS和MZR拟合结果进行了比较。在低红移样本中，流出宿主星系（流速v_flow ≤ -50 km s⁻¹）的 specific 恒星形成率（sSFR）提升了0.25至0.40 dex，中心金属丰度升高了0.04至0.06 dex；慢流入宿主星系（0 < v_flow < 100 km s⁻¹）的sSFR同样提升了0.20至0.30 dex，但无显著金属丰度偏移；而快流入宿主星系（v_flow ≥ 100 km s⁻¹）的恒星形成率增强程度较弱，金属丰度则略有降低。这些趋势共同支持了一种调控模型，即中性气体流示踪重子循环的不同阶段。慢流入宿主星系位于SFMS上方，这与吸积维持增强的恒星形成且未造成强中心金属丰度稀释的情况一致，可能表明流入气体已被金属富集，或在较长时间尺度上发生了混合或富集。相比之下，流出宿主星系位于SFMS的1σ上限附近，这与反馈调控后续成长的情况一致。气体流宿主星系在窄4000埃断裂强度（D_n4000）上，相对于红移、恒星质量和恒星形成率匹配的对照星系，还存在微小但系统的偏移。我们的结果表明，中性气体流与恒星形成主序和质量-金属丰度关系的星系群水平偏移相关，这与重子循环对标度关系弥散的贡献一致。
英文摘要
Gas inflows and outflows regulate galaxy growth, but direct observational links between measured gas flows and galaxy scaling relations remain limited. Using ~6,000 star-forming galaxies with down-the-barrel Na I D absorption from DESI DR2, we examine how systems with detected neutral-gas inflows and outflows populate the star-forming main sequence (SFMS) and mass-metallicity relation (MZR). Inflow and outflow hosts are compared with stellar-mass- and redshift-matched controls, and with SFMS and MZR fits derived from galaxies without detected gas flows. Outflow hosts (v_flow $\leq$ -50 km s$^{-1}$) show enhanced sSFRs by 0.25-0.40 dex and elevated central metallicities by 0.04-0.06 dex in the lower-redshift sample. Slow inflow hosts (0 $<$ v_flow $<$ 100 km s$^{-1}$) show similarly enhanced sSFRs of 0.20-0.30 dex, but no significant metallicity offset, while fast inflow hosts (v_flow $\geq$ 100 km s$^{-1}$) show weaker SFR enhancement and modestly lower metallicities. Together, these trends support a regulator picture in which neutral gas flows trace different phases of the baryon cycle. Slow inflow hosts lie above the SFMS, consistent with accretion sustaining enhanced star formation without strong central metallicity dilution. This may indicate that inflowing gas is already metal-enriched or has mixed or enriched over extended timescales. By contrast, outflow hosts lie near the upper 1{$σ$} SFMS envelope, consistent with feedback regulating subsequent growth. Gas-flow hosts also show small but systematic offsets in the narrow 4000 Å break strength ($D_n$4000) relative to controls matched in redshift, stellar mass and SFR. Our results show that neutral gas flows are associated with population-level offsets from the SFMS and MZR, consistent with a baryon-cycle contribution to scaling-relation scatter.
Comments16 pages, 11 figures, comments welcome, submitted to A&A
