Microlensing of Blended Stellar Images
Microlensing of Blended Stellar Images
复制标题
混合恒星图像的微透镜
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
B. Paczyński
中科院分区：
文献类型：
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作者：
P. Wozniak;B. Paczyński
流行的单微透镜光变曲线模型忽略了这样一种可能性，即只有一小部分光是由透镜状恒星产生的，其余部分是由紧密的、未解析的混合引起的，这可能与透镜有关或无关。不幸的是，混合的影响是显着的，因为所有微透镜实验都选择非常拥挤的场作为目标。双镜片之间的混合倾向是问题严重性的最直接证据。在本文中，我们指出单透镜事件拟合过程的强烈简并性，这使得在参数空间的很大一部分中很难检测到混合的存在，并且实际上不可能通过纯粹的光度测量手段对其进行校正。一些混合物可以通过天体测量手段检测到，但大多数必须进行统计校正。测量远低于地面探测极限的光度函数将很有帮助，例如使用哈勃太空望远镜（HST）。目标群中的双星会影响混合，并且可能无法用 HST 检测到；它们的存在将通过重复微透镜事件来揭示，因此可以在统计上纠正它们。如果不进行校正，那么事件时间尺度和透镜质量就会被系统地低估。
A popular model of single microlensing light curves neglects the possibility that only a fraction of the light is due to the lensed star, the remaining part being due to a close, unresolved blend, which may be related or unrelated to the lens. Unfortunately, the effects of blending are significant, as all microlensing experiments choose very crowded fields as their targets. The propensity of blends among double lenses is the most direct evidence for the seriousness of the problem. In this paper, we point out a strong degeneracy of the fitting procedure for single lensing events, which makes it very difficult to detect the presence of a blend, and practically impossible to correct for it by purely photometric means, in a large part of the parameter space. Some blends may be detected by astrometric means, but the majority have to be corrected for statistically. It will be helpful to measure the luminosity function well below the ground-based detection limit, e.g., using the Hubble Space Telescope (HST). Binary stars in the target population affect blending and may be undetectable with HST; their presence will be revealed by repeating microlensing events, so it will be possible to correct for them statistically. If no correction is made, then the event timescales and the lens masses are systematically underestimated.