发表机构
University of Vienna; Leiden University; Università degli Studi di Milano-Bicocca; University of Durham; University of Hull; University of Hertfordshire（维也纳大学; 莱顿大学; 米兰比可卡大学; 杜伦大学; 赫尔大学; 赫特福德大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究分析COLIBRE模拟中星系的中性星际介质，发现多相结构依赖于金属丰度，且热压力对加权方案敏感，观测示踪剂偏向高压区域。
AI 中文摘要
我们在COLIBRE流体动力学模拟中分析了红移z=0处星系的中性星际介质（ISM），并研究了这两种气体相在狭窄的热压力范围内共存的条件。COLIBRE星系是根据其星际介质的金属丰度来选择的。我们分析了多相星际介质热压力的中位数和质量加权分布，并将其与热平衡模型和观测结果进行了比较。气体金属丰度与太阳值相似的星系中的星际介质表现出清晰的多相结构，暖相和冷相在一定的热压力范围内共存。星际介质呈现多相时的压力取决于气体金属丰度。对于金属丰度较低（$Z_{\mathrm{ISM}}\lesssim0.1\\,\mathrm{Z}_{\odot}$）的COLIBRE星系，这种多相结构大部分消失，部分原因是分辨率限制。COLIBRE星系中中性相按HI质量加权的热压力低于但仍可与一些理论工作和观测估计相比较。热压力对加权方案表现出强烈的依赖性。如果按恒星形成率或CI质量加权，冷相的热压力与观测推导的结果相匹配。由此产生的压力取决于所假设的辐射场强度、尘埃丰度、有限分辨率和加权方案的组合。热压力对加权方案的强烈依赖性表明，用于估计热压力的观测示踪剂偏向于高压区域。
英文摘要
We analyse the neutral ISM of galaxies at redshift z=0 in the COLIBRE hydrodynamical simulations and investigate the conditions under which these two gas phases coexist in a narrow range of thermal pressures. COLIBRE galaxies are selected based on the metallicity of their ISM. The median and mass-weighted distributions of thermal pressures of the multiphase ISM are analysed and compared to thermal equilibrium models and observations. The ISM in galaxies with gas metallicities similar to solar values exhibits a clear multiphase structure with a warm and cold phase coexisting in a certain range of thermal pressures. The pressures at which the ISM is multiphase depend on the gas metallicity. For COLIBRE galaxies with lower metallicities ($Z_{\mathrm{ISM}}\lesssim0.1\,\mathrm{Z}_{\odot}$), this multiphase structure largely disappears, partly due to resolution. The thermal pressures weighted by the HI mass of the neutral phases in COLIBRE galaxies are lower than, but still comparable to, some theoretical works and observational estimates. The thermal pressures show a strong dependence on the weighting scheme. If weighted by the star formation rate or CI mass, the thermal pressures of the cold phase match those derived from observations. The resulting pressures depend on a combination of the assumed radiation field strength, dust abundance, limited resolution and the weighting scheme. The strong dependence of the thermal pressures on the weighting scheme indicates observational tracers used to estimate the thermal pressure are biased towards high-pressure regions.
