On the Observability of Individual Population III Stars and Their Stellar-mass Black Hole Accretion Disks through Cluster Caustic Transits
On the Observability of Individual Population III Stars and Their Stellar-mass Black Hole Accretion Disks through Cluster Caustic Transits
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DOI：
10.3847/1538-4365/aaa760
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发表时间：
2018-01
期刊：
影响因子：
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通讯作者：
R. Windhorst;F. Timmes;J. Wyithe;M. Alpaslan;S. Andrews;D. Coe;J. Diego;M. Dijkstra;S. Driver;P. Kelly;Duho Kim
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文献类型：
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作者：
R. Windhorst;F. Timmes;J. Wyithe;M. Alpaslan;S. Andrews;D. Coe;J. Diego;M. Dijkstra;S. Driver;P. Kelly;Duho Kim
我们总结了银河系外背景光的全色数据，给出了来自星族III恒星及其恒星质量黑洞周围可能的吸积盘在第一光时代的综合近红外表面亮度（SB）的上限，大致取自z≃7-17。理论预测和最近的近红外功率谱对它们的天空信号提供了更严格的限制。我们从MESA恒星演化模型中概述了零金属丰度星族III恒星的物理性质，通过氦耗尽和BH吸积盘。我们假设第二代非零金属量恒星可以以更高的倍数形成，因此黑洞吸积盘可能由来自低质量伴星的罗氏叶溢出供给。我们使用这些近红外SB约束来计算詹姆斯韦伯太空望远镜和下一代地面望远镜可能观测到的III星族恒星及其BH吸积盘透镜星团后面的焦性凌日的数量。对于km s−1的星团横向速度，典型的焦散放大倍数可以是小时上升次数和年下降次数。星团内介质天体的微透镜效应可以改变凌日放大倍率，但会延长可见时间。根据黑洞质量、吸积盘半径和进给效率，恒星质量的黑洞吸积盘焦散凌日的数量可能超过星族III恒星。要直接观测星族III的腐蚀性凌日，可能需要监测3-30个透镜星团，时间长达10年。
We summarize panchromatic Extragalactic Background Light data to place upper limits on the integrated near-infrared surface brightness (SB) that may come from Population III stars and possible accretion disks around their stellar-mass black holes (BHs) in the epoch of First Light, broadly taken from z ≃ 7–17. Theoretical predictions and recent near-infrared power spectra provide tighter constraints on their sky signal. We outline the physical properties of zero-metallicity Population III stars from MESA stellar evolution models through helium depletion and of BH accretion disks at . We assume that second-generation non-zero-metallicity stars can form at higher multiplicity, so that BH accretion disks may be fed by Roche-lobe overflow from lower-mass companions. We use these near-infrared SB constraints to calculate the number of caustic transits behind lensing clusters that the James Webb Space Telescope and the next-generation ground-based telescopes may observe for both Population III stars and their BH accretion disks. Typical caustic magnifications can be , with rise times of hours and decline times of year for cluster transverse velocities of km s−1. Microlensing by intracluster-medium objects can modify transit magnifications but lengthen visibility times. Depending on BH masses, accretion-disk radii, and feeding efficiencies, stellar-mass BH accretion-disk caustic transits could outnumber those from Population III stars. To observe Population III caustic transits directly may require monitoring 3–30 lensing clusters to mag over a decade.