论文标题
带有盖亚原始黑洞的天体微透明
Astrometric Microlensing of Primordial Black Holes with Gaia
论文作者
论文摘要
Gaia空间望远镜允许对星系中恒星的星体测量进行前所未有的精度。在这项工作中，我们探讨了盖亚（Gaia）通过PBH在背景恒星明显轨迹中会产生的扭曲来检测原始黑洞（PBH）暗物质的敏感性，这种效果称为Astromentres Micromemensing（AML）。我们提出了对镜头概率的新颖计算，并将其与现有的公开发布的Gaia EDR3恒星目录相结合，以预测Gaia将会看到的AML事件的预期率。我们还计算了一些可观察到的事件的预期分布，这对于减少背景非常有用。假设由于其他来源而引起的AML类似事件的天体物理背景率可以忽略不计，我们然后计算具有单色质量函数的PBHS参数空间的潜在排除。我们发现，Gaia对PBHS敏感在$ 0.4〜m_ \ odot $ -5 \ $ 5 \ times10^7〜m_ \ odot $，并且对$ \ sim 10〜m_ \ odot $的PBH具有峰值敏感性，因为它可以将其排除在$ 3 \ times10^\ 3 \ times10^^^^ - 4} $ compts $ compts $ 3 \ 4} $ p.凭借这种精致的灵敏度，盖亚有可能排除在Ligo/处女座看到的引力信号的PBH起源。我们对镜头概率的新颖计算首次包括中间持续时间镜头事件的效果，镜头事件持续了几年，但在一个时期仍然比Gaia Mission Lifetime短。我们预测的质量排除的下端对这类事件特别敏感。当发布GAIA的时间序列数据时，一旦我们对背景有了更好的了解，我们对镜头率和事件可观察到的分布的预测将有助于估计利用此数据的PBH参数空间的真实排除/发现。
The Gaia space telescope allows for unprecedented accuracy for astrometric measurements of stars in the Galaxy. In this work, we explore the sensitivity of Gaia to detect primordial black hole (PBH) dark matter through the distortions that PBHs would create in the apparent trajectories of background stars, an effect known as astrometric microlensing (AML). We present a novel calculation of the lensing probability, and we combine this with the existing publicly released Gaia eDR3 stellar catalog to predict the expected rate of AML events that Gaia will see. We also compute the expected distribution of a few event observables, which will be useful for reducing backgrounds. Assuming that the astrophysical background rate of AML like events due to other sources is negligible, we then compute the potential exclusion that could be set on the parameter space of PBHs with a monochromatic mass function. We find that Gaia is sensitive to PBHs in the range of $0.4~M_\odot$ - $5\times10^7~M_\odot$, and has peak sensitivity to PBHs of $\sim 10~M_\odot$ for which it can rule out as little as a fraction $3\times10^{-4}$ of dark matter composed of PBHs. With this exquisite sensitivity, Gaia has the potential to rule out a PBH origin for the gravitational wave signals seen at LIGO/Virgo. Our novel calculation of the lensing probability includes for the first time, the effect of intermediate duration lensing events, where the lensing event lasts for a few years, but for a period which is still shorter than the Gaia mission lifetime. The lower end of our predicted mass exclusion is especially sensitive to this class of events. As and when time-series data for Gaia is released, and once we have a better understanding of the backgrounds, our prediction of the lensing rate and event observable distributions will be useful to estimate the true exclusion/discovery of the PBH parameter space utilizing this data.
