arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0905.4738astro-ph.CO
收藏

矮星系质量范围II中暗晕的强透镜:探测概率

Strong Lensing by Subhalos in the Dwarf-Galaxy Mass Range II: Detection Probabilities

T. Riehm, E. Zackrisson, E. Mortsell, K. Wiik

摘要:

目前的冷暗物质模拟预测的暗晕子结构,原则上可以通过类星体在小角尺度(0.01弧秒或以下)上的强透镜图像分裂来检测。在这里,我们估计的总体概率透镜的子结构在主机晕密切对准视线的背景类星体。在类星体可以近似为点源的假设下,由暗晕产生的强引力透镜的光学深度通常很小(τ < 0.01),这与之前的说法相反。因此,我们的结论是,它是目前不可行的,使用这种策略,把模拟预测的暗物质晕下人口的测试。然而,如果假设源在空间上是扩展的,就像在无线电波长观测到的类星体一样,只要角分辨率足够,即使在距宿主星系相当大的投影距离上,也有合理的可能性看到子结构透镜效应。虽然多重成像的射电类星体将是明确探测暗物质暗晕的最佳目标,但即使是单一成像的射电类星体也可能有助于设定暗晕丰度和中心表面质量密度的上限。

英文摘要:

The dark halo substructures predicted by current cold dark matter simulations may in principle be detectable through strong-lensing image splitting of quasars on small angular scales (0.01 arcseconds or below). Here, we estimate the overall probabilities for lensing by substructures in a host halo closely aligned to the line of sight to a background quasar. Under the assumption that the quasar can be approximated as a point source, the optical depth for strong gravitational lensing by subhalos typically turns out to be very small (tau < 0.01), contrary to previous claims. We therefore conclude that it is currently not feasible to use this strategy to put the simulation predictions for the dark matter subhalo population to the test. However, if one assumes the source to be spatially extended, as is the case for a quasar observed at radio wavelengths, there is a reasonable probability for witnessing substructure lensing effects even at rather large projected distances from the host galaxy, provided that the angular resolution is sufficient. While multiply-imaged, radio-loud quasars would be the best targets for unambiguously detecting dark matter subhalos, even singly-imaged radio quasars might be useful for setting upper limits on the abundance and central surface mass density of subhalos.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑