The nongravitational interactions of dark matter in colliding galaxy clusters
The nongravitational interactions of dark matter in colliding galaxy clusters
复制标题
DOI：
10.1126/science.1261381
复制
发表时间：
2015-03
期刊：
影响因子：
56.9
通讯作者：
D. Harvey;R. Massey;T. Kitching;A. Taylor;E. Tittley
中科院分区：
文献类型：
--
作者：
D. Harvey;R. Massey;T. Kitching;A. Taylor;E. Tittley
暗物质的想法得到了广泛的支持，但两个主要的问题仍然存在：所谓的标准模型排除了它，它不能被任何望远镜直接探测到。目前，天文学家只能间接地观察暗物质的影响，例如当观察看不见的生物扰动池塘表面时。哈维等人观察了72个星系碰撞，以比较气体和恒星（直接观察）以及暗物质（推断）的质量中心。根据这些偏移量，暗物质显然存在。《科学》，本期第1462页，星系合并的观测提供了对暗物质所产生的拖曳力的限制。星系团之间的碰撞提供了对作用于暗物质的非引力的测试。暗物质在“子弹团”碰撞中没有减速，这限制了它的自相互作用截面σDM/m < 1.25平方厘米每克（cm 2/g）[68%置信限（CL）]（σDM，自相互作用截面; m，暗物质的单位质量）。利用钱德拉和哈勃太空望远镜，我们现在已经观察到72次碰撞，包括主要和次要的合并。结合这些测量统计，我们检测到暗质量的存在在7.6σ的显着性。暗物质的位置在5.8 ± 8.2千秒差距的关联恒星范围内保持紧密排列，这意味着自相互作用截面σDM/m < 0.47 cm 2/g（95% CL），并且不利于标准模型的一些建议扩展。
Uncloaking the influence of the invisible actor The idea of dark matter enjoys popular support, but two major concerns persist: the so-called Standard Model excludes it, and it cannot be directly detected by any telescope. For now, astronomers can only observe dark matter's influence indirectly, such as when watching unseen creatures perturb the surface of a pond. Harvey et al. observed 72 galaxy collisions to compare the resulting centers of mass for the gas and stars (from direct observations) and for the dark matter (by inference). Based on these offsets, dark matter is clearly present. Science, this issue p. 1462 Observations of galactic mergers offer constraints on the drag forces incurred by dark matter. Collisions between galaxy clusters provide a test of the nongravitational forces acting on dark matter. Dark matter’s lack of deceleration in the “bullet cluster” collision constrained its self-interaction cross section σDM/m < 1.25 square centimeters per gram (cm2/g) [68% confidence limit (CL)] (σDM, self-interaction cross section; m, unit mass of dark matter) for long-ranged forces. Using the Chandra and Hubble Space Telescopes, we have now observed 72 collisions, including both major and minor mergers. Combining these measurements statistically, we detect the existence of dark mass at 7.6σ significance. The position of the dark mass has remained closely aligned within 5.8 ± 8.2 kiloparsecs of associated stars, implying a self-interaction cross section σDM/m < 0.47 cm2/g (95% CL) and disfavoring some proposed extensions to the standard model.