论文标题
大型光谱调查时代的冷气质量测量
Cold gas mass measurements for the era of large optical spectroscopic surveys
论文作者
论文摘要
气体在星系形成和进化中的许多过程中起着重要作用，但是量化气体的重要性已受到挑战，即测量大型星系样本的气体质量。直接原子和分子气体测量的数据集足以建立简单的比例关系，但通常不足以量化三参数关系或二阶依赖关系。作为另一种方法，我们在这里使用SDSS主星系样品和Phangs-Muse调查中的星系的光电离电离模型从光学发射线中得出间接的冷气测量。我们使用XCold Gass和Phangs-Alma分子气体测量值对气体表面密度测量进行校准，以确保我们的测量值可靠。我们证明了考虑到光学深度（$τ_v$）与气体表面密度（$σ_{gas} $）之间关系的规模依赖性的重要性，并提供了从$τ_v$，金属和尘埃至中等比率的一般处方，以估算$σ_{gas} $。为了证明间接冷气质量足够准确，可以量化气体在星系进化中的作用，我们研究了SDSS星系的质量金属关系（MZR），并表明，作为第三个参数，气体质量在减少关系散射时优于SFR，如模型和模拟所预测的。
Gas plays an important role in many processes in galaxy formation and evolution, but quantifying the importance of gas has been hindered by the challenge to measure gas masses for large samples of galaxies. Datasets of direct atomic and molecular gas measurements are sufficient to establish simple scaling relations, but often not large enough to quantify three-parameter relations, or second order dependencies. As an alternative approach, we derive here indirect cold gas measurements from optical emission lines using photoionization models for galaxies in the SDSS main galaxy sample and the PHANGS-MUSE survey. We calibrate the gas surface density measurements using xCOLD GASS and PHANGS-ALMA molecular gas measurements to ensure our measurements are reliable. We demonstrate the importance of taking into account the scale-dependence of the relation between optical depth ($τ_V$) and gas surface density ($Σ_{gas}$) and provide a general prescription to estimate $Σ_{gas}$ from $τ_V$, metallicity and the dust-to-metal ratio, at any arbitrary physical resolution. To demonstrate that the indirect cold gas masses are accurate enough to quantify the role of gas in galaxy evolution, we study the mass-metallicity relation (MZR) of SDSS galaxies and show that as a third parameter, gas mass is better than SFR at reducing the scatter of the relation, as predicted by models and simulations.
