标题： 用强透镜效应探测星系团中的暗物质核心 显示英文标题

标题： Detecting Dark Matter Cores in Galaxy Clusters with Strong Lensing

摘要： 我们测试了强透镜数据约束星系团暗物质晕中心核大小的能力，以Abell 611作为原型。 使用模拟数据，我们展示了在引力势中具有椭圆性的星团晕模型可能会使推断出的质量和浓度产生偏差，这可能在加入弱透镜或X射线数据时使推断出的中心密度产生偏差。 我们还强调了如果径向密度分布与假设模型不同，可能会出现核心大小的虚假约束。 如果数据中存在中心图像，这些系统性误差可以得到缓解。 将我们的方法应用于Abell 611，并对恒星质量-光度比施加合理的先验限制，将核心大小限制在大约4千秒差距以内，在0.2位置误差下最小化$\chi^2$为0.28。 如此小的核心暗示了暗物质自相互作用截面的约束约为$0.1\ \mathrm{cm^2/g}$，在相对速度约为1500公里/秒的情况下。 显示英文摘要

摘要： We test the ability of strong lensing data to constrain the size of a central core in the dark matter halos of galaxy clusters, using Abell 611 as a prototype. Using simulated data, we show that modeling a cluster halo with ellipticity in the gravitational potential can bias the inferred mass and concentration, which may bias the inferred central density when weak lensing or X-ray data are added. We also the highlight the possibility for spurious constraints on the core size if the radial density profile is different from the assumed model. These systematics can be ameliorated if central images are present in the data. Applying our methodology to Abell 611 and imposing a reasonable prior on the stellar mass-to-light ratio restricts the core size to be less than about 4 kpc, with a minimum reduced $\chi^2$ of 0.28 for 0."2 positional errors. Such small cores imply a constraint on the dark matter self-interaction cross section of the order of $0.1\ \mathrm{cm^2/g}$ at relative velocities of about 1500 km/s.