Jain B
Astrophys J. 2000 Feb 10;530(1):L1-L4. doi: 10.1086/312480.
We present a new approach to measure the mass function of dark matter halos and to discriminate models with differing values of Omega through weak gravitational lensing. We measure the distribution of peaks from simulated lensing surveys and show that the lensing signal due to dark matter halos can be detected for a wide range of peak heights. Even when the signal-to-noise ratio is well below the limit for detection of individual halos, projected halo statistics can be constrained for halo masses spanning galactic to cluster halos. The use of peak statistics relies on an analytical model of the noise due to the intrinsic ellipticities of source galaxies. The noise model has been shown to accurately describe simulated data for a variety of input ellipticity distributions. We show that the measured peak distribution has distinct signatures of gravitational lensing, and its non-Gaussian shape can be used to distinguish models with different values of Omega. The use of peak statistics is complementary to the measurement of field statistics, such as the ellipticity correlation function, and is possibly not susceptible to the same systematic errors.
我们提出了一种新方法，通过弱引力透镜效应来测量暗物质晕的质量函数，并区分具有不同Ω值的模型。我们测量了模拟透镜调查中峰值的分布，并表明对于广泛的峰值高度范围，都可以检测到由暗物质晕引起的透镜信号。即使信噪比远低于单个晕的检测极限，对于从星系晕到星系团晕的各种晕质量，投影晕统计量也可以受到约束。峰值统计量的使用依赖于一个关于源星系固有椭圆率所产生噪声的解析模型。该噪声模型已被证明能够准确描述各种输入椭圆率分布的模拟数据。我们表明，测量到的峰值分布具有引力透镜效应的独特特征，其非高斯形状可用于区分具有不同Ω值的模型。峰值统计量的使用与场统计量（如椭圆率相关函数）的测量互为补充，并且可能不易受到相同系统误差的影响。
