Values of H0 from Models of the Gravitational Lens 0957+561
Values of H0 from Models of the Gravitational Lens 0957+561
复制标题
引力透镜模型中的 H0 值 0957 561
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
P. Fischer
中科院分区：
文献类型：
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作者：
G. Bernstein;P. Fischer
透镜双类星体0957+561具有很好的测量时间延迟，因此对全球H0的测定是有用的。透镜质量分布的不确定性是推导出的H0的最大不确定度来源。我们调查了一组透镜模型产生的H0的范围，这些透镜模型旨在模拟天体物理上看似合理的质量分布的全范围，使用已检测到的大量多重成像源作为约束。只有当我们包括来自星系团的影响，而不是恒定的局部放大和剪切时，我们才能获得对所有观测数据的第一次适当的拟合。透镜星系和周围的星系团也必须偏离圆形对称性。透镜模型与观测结果一致，达到95%的置信度(CL)，表明H0=104(1-)公里S-1 MPC-1。以前的弱透镜测量将G130“范围内的平均质量密度限制为=0.26±0.16(95%CL)，这意味着H0=77公里S-1 MPC-1(95%CL)。最适合的型号包括65-80公里的S-1 MPC-1。进一步的观测将缩小质量模型和的可信区间。我们的透镜模型的全色域所允许的H0范围比仅考虑简单的幂函数密度分布所隐含的范围要大得多。因此，我们告诫不要使用简单的等温或幂定律质量模型来从其他时滞系统中获得H0。高信噪比成像多个或扩展的透镜特征将大大减少H0的不确定性，当将复杂的模型安装到延时透镜上时。
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 H0 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 that have been detected. We obtain the first adequate fit to all the observations 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 that are consistent with observations to 95% confidence level (CL) indicate H0 = 104(1 - ) km s-1 Mpc-1. Previous weak-lensing measurements constrain the mean mass density within 30″ of G1 to be = 0.26 ± 0.16 (95% CL), implying H0 = 77 km s-1 Mpc-1 (95% CL). The best-fitting models span the range 65–80 km s-1 Mpc-1. Further observations will shrink the confidence interval for both the mass model and . 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 using simple isothermal or power-law mass models to derive H0 from other time-delay systems. High signal-to-noise ratio imaging of multiple or extended lensed features will greatly reduce the H0 uncertainties when fitting complex models to time-delay lenses.