Over the past decade increasingly robust estimates of the dense molecular gas content in galaxy populations between redshift 0 and the peak of cosmic galaxy/star formation from redshift 1-3 have become available. This rapid progress has been possible due to the advent of powerful ground-based, and space telescopes for combined study of several millimeter to far-IR, line or continuum tracers of the molecular gas and dust components. The main conclusions of this review are: 1. Star forming galaxies contained much more molecular gas at earlier cosmic epochs than at the present time. 2. The galaxy integrated depletion time scale for converting the gas into stars depends primarily on z or Hubble time, and at a given z, on the vertical location of a galaxy along the star-formation rate versus stellar mass "main-sequence" (MS) correlation. 3. Global rates of galaxy gas accretion primarily control the evolution of the cold molecular gas content and star formation rates of the dominant MS galaxy population, which in turn vary with the cosmological expansion. A second key driver may be global disk fragmentation in high-z, gas rich galaxies, which ties local free-fall time scales to galactic orbital times, and leads to rapid radial matter transport and bulge growth. Third, the low star formation efficiency inside molecular clouds is plausibly set by super-sonic streaming motions, and internal turbulence, which in turn may be driven by conversion of gravitational energy at high-z, and/or by local feedback from massive stars at low-z. 4. A simple 'gas regulator' model is remarkably successful in predicting the combined evolution of molecular gas fractions, star formation rates, galactic winds, and gas phase metallicities.

中文翻译：

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跨宇宙时间的恒星形成星际介质的演化

在过去的十年中，对红移 0 和宇宙星系/恒星形成峰值（红移 1-3）之间星系群中稠密分子气体含量的估计越来越可靠。由于强大的地面和空间望远镜的出现，可以对分子气体和尘埃成分的几毫米到远红外、线或连续谱示踪剂进行联合研究，从而使这种快速进展成为可能。这篇综述的主要结论是： 1. 恒星形成星系在更早的宇宙时代比现在含有更多的分子气体。2. 将气体转化为恒星的星系综合耗竭时间尺度主要取决于 z 或哈勃时间，并且在给定 z 时，取决于星系沿恒星形成率与恒星质量“主序”的垂直位置（ MS) 相关性。3. 星系气体吸积的全球速率主要控制着主导 MS 星系群的冷分子气体含量和恒星形成率的演变，而这又随着宇宙膨胀而变化。第二个关键驱动因素可能是高z、富含气体的星系中的全球圆盘碎片，这将局部自由落体时间尺度与星系轨道时间联系起来，并导致快速的径向物质传输和膨胀增长。第三，分子云内部的低恒星形成效率似乎是由超音速流运动和内部湍流造成的，而内部湍流又可能是由高 z 处的引力能量转换和/或来自大质量恒星的局部反馈驱动的。低 z。4. 一个简单的“气体调节器”模型在预测分子气体组分、恒星形成率、