标题： 宇宙学的星系团X射线形态限制 显示英文标题

标题： COSMOLOGICAL CONSTRAINTS FROM CLUSTER X-RAY MORPHOLOGIES

摘要： 我们利用由爱因斯坦IPC观测的65个星系团组成的代表性样本，限制了星系团X射线形态的范围。我们开发并应用定量且可重复的测量方法来限制发射加权质心变化、轴比、方向以及径向衰减的固有分布。然后，我们利用星系团X射线形态的范围来限制三种通用宇宙学模型（Omega=1，Omega_0=0.2，和Omega_0=0.2 & lambda_0=0.8）。对于每种模型，我们生成了八组与在星系团尺度上有效功率谱$P(k)\propto k^{-1}$一致的高斯随机初始条件。使用这24个数值模拟的星系团样本，我们将观测到的星系团和模拟星系团的X射线形态进行比较。这些比较表明：(i) 星系团质心变化、轴比和径向衰减对潜在的宇宙学模型敏感；(ii) 在低Omega_0宇宙学中，具有观测到的X射线形态范围的星系团是非常不可能存在的。分析倾向于Omega=1模型，尽管仍存在一些差异。我们讨论了改变初始条件和在模拟中加入额外物理效应的影响。 显示英文摘要

摘要： We use a representative sample of 65 galaxy clusters observed with the Einstein IPC to constrain the range of cluster X-ray morphologies. We develop and apply quantitative and reproducible measures to constrain the intrinsic distributions of emission weighted centroid variation, axial ratio, orientation, and the radial fall--off. We then use the range of cluster X--ray morphologies to constrain three generic cosmological models (Omega=1, Omega_0=0.2, and Omega_0=0.2 & lambda_0=0.8). For each of these models, we evolve eight sets of Gaussian random initial conditions consistent with an effective power spectrum $P(k)\propto k^{-1}$ on cluster scales. Using this sample of 24 numerical cluster simulations, we compare the X--ray morphologies of the observed and simulated clusters. The comparisons indicate that: (i) cluster centroid variations, axial ratios, and radial fall-offs are sensitive to the underlying cosmological model, and (ii) galaxy clusters with the observed range of X--ray morphologies are very unlikely in low Omega_0 cosmologies. The analysis favors the Omega=1 model, though some discrepancies remain. We discuss the effects of changing the initial conditions and including additional physics in the simulations.