发表机构
University of Oulu; DARK, Niels Bohr Institute, University of Copenhagen; Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona; INAF – Padova Astronomical Observatory（奥卢大学; 哥本哈根大学尼尔斯·玻尔研究所DARK; 巴塞罗那大学宇宙科学研究所; 意大利国家天体物理研究所帕多瓦天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对低质量低SFR的矮不规则星系，通过分层贝叶斯推断发现≈2%的超新星效率可普适解释恒星形成主序星系的HI湍流，为星系演化模型反馈方案提供约束。
AI 中文摘要
星系中冷气体湍流的起源长期存在争议，超新星（SNe）作为恒星反馈的主导形式，曾被认为不足以维持对抗耗散的湍流，尤其是在恒星形成率（SFR）较低的星系环境中。我们研究矮不规则星系中中性原子气体（HI）湍流的起源，这是一个质量和SFR都较低的挑战性区域。我们基于近期关于旋涡星系的研究，该研究表明星系盘延展可延长耗散时标，减少维持湍流所需的能量，从而使超新星反馈变得可行。我们测量14个矮星系中的超新星效率，即维持HI湍流所需的超新星能量占比，并检验在恒星形成主序的代表性样本中是否存在“普适”效率。从观测到的HI分布和运动学，我们推导单位面积HI动能的径向分布，并将其建模为热能与超新星湍流能量的总和，以观测到的SFR面密度为约束。我们将纯冷中性介质和暖中性介质（WNM）相作为极限情况，同时考虑混合两相场景，通过分层贝叶斯推断获得超新星效率和WNM占比。我们发现，矮星系中观测到的HI动能仅需要超新星能量的≤3%，且≈2%的“普适”效率可解释我们主序样本中的HI湍流。我们的发现表明，超新星效率在不同性质的星系中保持相似，为星系演化模型中的反馈方案提供了重要约束。
英文摘要
The origin of cold gas turbulence in galaxies has long been debated. Supernovae (SNe), the dominant form of stellar feedback, were thought insufficient to sustain it against dissipation, especially in galactic environments with low star formation rates (SFRs). We investigate the origin of the neutral atomic gas (HI) turbulence in dwarf irregular galaxies, a challenging regime of low masses and SFRs. We build on a recent study of spirals showing that disc flaring prolongs the dissipation timescale, reducing the energy needed to sustain turbulence and making SN feedback viable. We measure the SN efficiency, that is the fraction of SN energy required to sustain HI turbulence, in 14 dwarfs, and test whether a "universal" efficiency holds across a sample representative of the star-forming main sequence. From the observed HI distributions and kinematics, we derive the radial profiles of the HI kinetic energy per unit area and model them as the sum of thermal energy and turbulent energy from SNe, constrained by the observed SFR surface density. We consider pure cold and warm neutral medium (WNM) phases as limiting cases, as well as a mixed two-phase scenario, obtaining the SN efficiency and WNM fraction via hierarchical Bayesian inference. We find that the observed HI kinetic energy in dwarfs requires only $\lesssim 3\%$ of the SN energy, and that a "universal" efficiency of $\approx 2\%$ explains the HI turbulence across our main-sequence sample. Our findings suggest that the SN efficiency remains similar across galaxies with different properties, offering valuable constraint for feedback recipes in galaxy evolution models.
CommentsAccepted for publication in A&A on 24/09/2026. 20 pages, 10 figures, 3 tables
