标题： 0957+561引力透镜模型的H_0值 显示英文标题

标题： Values of H_0 from Models of the Gravitational Lens 0957+561

摘要： 透镜化双类星体0957+561具有精确测量的时间延迟，因此对于全球确定H0是有用的。 透镜质量分布的不确定性是推导出的H0的最大不确定性来源。 我们研究了一组旨在模拟天体物理上合理质量分布范围的透镜模型所产生的\hn 的范围，使用了大量已被检测到的多重成像源作为约束条件。 我们获得了对所有观测的第一个充分拟合，但前提是除了恒定的局部放大率和剪切外，还包括来自星系团的影响。 透镜星系和周围的星系团都必须偏离圆形对称性。 与观测结果在95%置信水平一致的透镜模型表明 H0=104^{+31}_{-23}(1-\kthirty ) km/s/Mpc。 以前的弱透镜测量限制了G1周围30"内的平均质量密度为kthirty=0.26+/-0.16 (95% CL)，意味着H0=77^{+29}_{-24}km/s/Mpc (95% CL)。 最佳拟合模型的范围是65--80 km/s/Mpc。 进一步的观测将缩小质量模型和\kthirty 的置信区间。 我们透镜模型的全部范围所允许的H0范围明显大于仅考虑简单幂律密度剖面时所暗示的范围。 因此，我们警告不要在从其他时间延迟系统推导H0时使用简单的等温或幂律质量模型。 对多个或扩展的透镜特征进行高信噪比成像将大大减少在对时间延迟透镜拟合复杂模型时的H0不确定性。 显示英文摘要

摘要： The lensed double QSO 0957+561 has a well-measured time delay and hence is useful for a global determination of H0. Uncertainty in the mass distribution of the lens is the largest source of uncertainty in the derived H0. We investigate the range of \hn produced by a set of lens models intended to mimic the full range of astrophysically plausible mass distributions, using as constraints the numerous multiply-imaged sources which have been detected. We obtain the first adequate fit to all the observations, but only if we include effects from the galaxy cluster beyond a constant local magnification and shear. Both the lens galaxy and the surrounding cluster must depart from circular symmetry as well. Lens models which are consistent with observations to 95% CL indicate H0=104^{+31}_{-23}(1-\kthirty) km/s/Mpc. Previous weak lensing measurements constrain the mean mass density within 30" of G1 to be kthirty=0.26+/-0.16 (95% CL), implying H0=77^{+29}_{-24}km/s/Mpc (95% CL). The best-fitting models span the range 65--80 km/s/Mpc. Further observations will shrink the confidence interval for both the mass model and \kthirty. The range of H0 allowed by the full gamut of our lens models is substantially larger than that implied by limiting consideration to simple power law density profiles. We therefore caution against use of simple isothermal or power-law mass models in the derivation of H0 from other time-delay systems. High-S/N imaging of multiple or extended lensed features will greatly reduce the H0 uncertainties when fitting complex models to time-delay lenses.