论文标题
气体积聚和AGN反馈对质量金属关系散射的影响
The impact of gas accretion and AGN feedback on the scatter of the mass-metallicity relation
论文作者
论文摘要
星系的气相金属性编码有关星系进化过程的重要信息，尤其是恒星形成，反馈，流出和气体积聚，其相对重要性可以从质量金属关系（MZR）散布的系统趋势中提取。在这里，我们使用来自SDSS的低红移（0.02 <Z <0.055）星系的样本来研究MZR周围散点的性质，可观察到的物理过程，从而导致它及其对星系质量的依赖性。我们使用Scholte＆Saintonge（2023）技术从光发射线推断出的冷气质量来确认在固定恒星质量下，金属性和气体质量是抗相关的，但仅适用于高达M*= 10^{10.5} MSUN的星系。在这种质量状态下，我们使用两点相关函数的幅度作为光环质量的代理，发现了星系对MZR和Halo质量的偏移之间的联系；在固定的恒星质量下，最贫穷的星系属于最大的光晕。该观察结果与对星系的气体积聚速率的变化一致，这是光晕质量的函数，环境影响对卫星星系的作用也有所促进。在较高的恒星质量下，MZR的散射不再与气体或光晕质量相关。取而代之的是，正如模型和模拟所期望的那样，有一些与AGN活性联系的迹象，即金属性是由气体内和流出之间的相互作用，恒星形成和AGN反馈之间的相互作用，从而塑造了MZR及其散布。
The gas-phase metallicity of galaxies encodes important information about galaxy evolution processes, in particular star formation, feedback, outflows and gas accretion, the relative importance of which can be extracted from systematic trends in the scatter of the mass-metallicity relation (MZR). Here, we use a sample of low redshift (0.02 < z < 0.055) galaxies from SDSS to investigate the nature of the scatter around the MZR, the observables and physical processes causing it, and its dependence on galaxy mass. We use cold gas masses inferred from optical emission lines using the technique of Scholte & Saintonge (2023) to confirm that at fixed stellar mass, metallicity and gas mass are anti-correlated, but only for galaxies up to M*= 10^{10.5} Msun. In that mass regime, we find a link between the offset of a galaxy from the MZR and halo mass, using the amplitude of the two-point correlation function as a proxy for halo mass; at fixed stellar mass, the most gas-poor galaxies reside in the most massive halos. This observation is consistent with changes in gas accretion rates onto galaxies as a function of halo mass, with environmental effects acting on satellite galaxies also contributing. At higher stellar masses, the scatter of the MZR does no longer correlate with gas or halo mass. Instead, there is some indication of a link with AGN activity, as expected from models and simulations that metallicity is set by the interplay between gas in- and outflows, star formation, and AGN feedback, shaping the MZR and its scatter.
