Gravitational Lens Time Delays in Cold Dark Matter
Gravitational Lens Time Delays in Cold Dark Matter
复制标题
冷暗物质中的引力透镜时间延迟
DOI：
10.1086/345342
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
C. Kochanek
中科院分区：
文献类型：
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作者：
C. Kochanek
在标准冷暗物质 (CDM) 晕模型中，引力透镜的时间延迟由可见星系相对于整个晕的冷重子质量分数 fb = Ωb, Cold/Ω0 决定。仅当 fb ≳ 0.2（单边 68% 置信度）大于上限时，PG 1115+080、SBS 1520+530、B1600+434 和 HE 2149-2745 中观测到的时间延迟给出的哈勃常数与哈勃太空望远镜关键项目值 H0 = 72 ± 8 km s-1 Mpc-1 一致fb, max = Ωb/Ω0 = 0.15 ± 0.05 根据宇宙微波背景估算。如果所有可用重子都冷却且 fb = fb, max，则时间延迟意味着 H0 = 65 ± 6 km s-1 Mpc-1（95% 置信度）。如果冷重子的局部库存 fb ≃ 0.013/h70 是正确的，则 H0 = 52 ± 6 km s-1 Mpc-1 并且晕参数与等温质量模型密切匹配。等温模型也与这些尺度上的强弱透镜研究、恒星动力学和 X 射线观测一致，而更集中的模型则不然。引力透镜时间延迟、局部距离尺度和标准 CDM 光晕模型之间存在冲突。
In standard cold dark matter (CDM) halo models, the time delay of a gravitational lens is determined by the cold baryon mass fraction, fb = Ωb, cold/Ω0, of the visible galaxy relative to the overall halo. The observed time delays in PG 1115+080, SBS 1520+530, B1600+434, and HE 2149-2745 give Hubble constants consistent with the Hubble Space Telescope Key Project value of H0 = 72 ± 8 km s-1 Mpc-1 only if fb ≳ 0.2 (one-sided 68% confidence), which is larger than the upper bound of fb, max = Ωb/Ω0 = 0.15 ± 0.05 estimated from the cosmic microwave background. If all available baryons cool and fb = fb, max, then the time delays imply H0 = 65 ± 6 km s-1 Mpc-1 (95% confidence). If local inventories of cold baryons, fb ≃ 0.013/h70, are correct, then H0 = 52 ± 6 km s-1 Mpc-1 and the halo parameters closely match isothermal mass models. Isothermal models are also consistent with strong and weak lens studies, stellar dynamics, and X-ray observations on these scales, while significantly more centrally concentrated models are not. There is a conflict between gravitational lens time delays, the local distance scale, and standard CDM halo models.