标题： 星系盘中的压力支持：对旋转曲线和暗物质密度分布的影响 显示英文标题

标题： Pressure Support in Galaxy Disks: Impact on Rotation Curves and Dark Matter Density Profiles

摘要： 旋转曲线在假设观测到的旋转产生向心力，正好平衡重力向内的力的情况下，限制了星系的潜在质量密度分布。 然而，大多数旋转曲线是通过气体发射线测量的，这些气体可能会受到压力的影响。 在真实的星系盘中，气体压力随着半径的增加而减小，为盘提供额外的径向支持。 因此，测量的切向旋转速度往往会滞后于测试粒子的真实圆周速度。 气体压力主要由湍流主导，我们从最近的气体速度弥散和表面密度估计中评估其可能的幅度。 我们表明，当旋转曲线的幅度与星际湍流的特征速度相当时，压力支持可能导致对暗物质晕的质量密度和密度分布内部斜率的低估。 这些效应对于旋转速度小于75公里/秒的星系可能很重要，但在更高质量的星系中不太可能重要。 我们发现，由于气体转化为恒星导致的支持减少会被气体的向内流动所补偿，因此压力支持可以在长时间尺度上维持。 然而，我们指出在评估压力支持在星系中的重要性时存在许多不确定性。 因此，尽管压力支持可能缓解在千秒差距尺度上旋转曲线观测与LambdaCDM之间的可能矛盾，但目前不应将其视为最终解决方案。 显示英文摘要

摘要： Rotation curves constrain a galaxy's underlying mass density profile, under the assumption that the observed rotation produces a centripetal force that exactly balances the inward force of gravity. However, most rotation curves are measured using emission lines from gas, which can experience additional forces due to pressure. In realistic galaxy disks, the gas pressure declines with radius, providing additional radial support to the disk. The measured tangential rotation speed will therefore tend to lag the true circular velocity of a test particle. The gas pressure is dominated by turbulence, and we evaluate its likely amplitude from recent estimates of the gas velocity dispersion and surface density. We show that where the amplitude of the rotation curve is comparable to the characteristic velocities of the interstellar turbulence, pressure support may lead to underestimates of the mass density of the underlying dark matter halo and the inner slope of its density profile. These effects may be significant for galaxies with rotation speeds <75km/s, but are unlikely to be significant in higher mass galaxies. We find that pressure support can be sustained over long timescales, because any reduction in support due to the conversion of gas into stars is compensated for by an inward flow of gas. However, we point to many uncertainties in assessing the importance of pressure support in galaxies. Thus, while pressure support may alleviate possible tensions between rotation curve observations and LambdaCDM on kiloparsec scales, it should not be viewed as a definitive solution at this time.