论文标题
在星系周围流动。 I.星系连通性对宇宙环境的依赖性及其对恒星形成率的影响
Flows around galaxies. I. The dependency of galaxy connectivity on cosmic environments and effects on the star-formation rate
论文作者
论文摘要
为了使星系如何获取其恒星材料的基本问题，我们介绍了与宇宙环境相关的星系连通性的第一个全面特征（即，与银河相关的小规模丝状流的数量），以及连接率的统计探索Z = 2 2 = 22。我们通过将分散细丝查找器应用于2942个中央星系（$ M_*> 10> 10^{8} $ $ $ $ $ $ \ MATHRM {M} _ \ odot / H $），通过将分散丝查找器应用于DM密度，直接连接到星系中的KPC尺度丝。我们的结果表明，星系连通性跨越了一个广泛的范围（从0到9），超过一半的星系连接到两个或三个流。我们检查了可能影响连通性的多种因素，发现其随着质量的增加，质量下降，而局部密度降低，并且不依赖于Delaunay Tessellation估计的局部环境，而对于高质量星系。我们根据它们在不同宇宙网络环境中的位置进一步对星系进行分类，并强调了大规模结构对连接流数量的影响。我们的结果反映了宇宙潮汐的不同优势，这可以防止形成喂养星系的相干流，甚至可以从其本地网络中脱离星系。最后，我们表明，在固定的局部密度下，由于连通性，低质量星系的恒星形成率（SFR）高达$5.9σ$。对于嵌入在宇宙丝中的星系，这种SFR提升更为重要（$6.3σ$），那里可用的物质储层很大。对于高质量星系，发现了较轻的影响，暗示了通过小质量星系中小规模流的物质流入的不同相对效率。
With the aim of bringing substantial insight to the fundamental question of how galaxies acquire their material for star-formation, we present the first comprehensive characterisation of the galaxy connectivity (i.e. the number of small-scale filamentary streams connected to a galaxy) in relation with the cosmic environment, and a statistical exploration of the impact of connectivity on the star-formation rate at z=2. We detect kpc-scale filaments directly connected to galaxies by applying the DisPerSE filament finder to the DM density around 2942 central galaxies ($M_* > 10^{8}$ $\mathrm{M}_\odot / h$) of the TNG50-1 simulation. Our results demonstrate that galaxy connectivity spans a broad range (from 0 to 9), with more than half of the galaxies connected to two or three streams. We examine a variety of factors that could influence the connectivity finding out that it increases with mass, decreases with local density for low mass galaxies, and does not depend on local environment, estimated by the Delaunay tessellation, for high mass galaxies. We further classify galaxies according to their location in different cosmic web environments, and we highlight the influence of the large-scale structure on the number of connected streams. Our results reflect the different strengths of the cosmic tides, which can prevent the formation of coherent streams feeding the galaxies, or even disconnect the galaxy from its local web. Finally, we show that, at fixed local density, the star-formation rate (SFR) of low mass galaxies is up to $5.9σ$ enhanced due to connectivity. This SFR boost is even more significant ($6.3σ$) for galaxies embedded in cosmic filaments, where the available matter reservoirs are large. A milder impact is found for high mass galaxies, hinting at different relative efficiencies of matter inflow via small-scale streams in galaxies of different masses.
