Photometric constraints on white dwarfs and the identification of extreme objects
Photometric constraints on white dwarfs and the identification of extreme objects
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DOI：
10.1111/j.1365-2966.2009.15351.x
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发表时间：
2008-10
影响因子：
4.8
通讯作者：
D. Mortlock;H. Peiris;Zeljko Ivezic Imperial College London;U. Cambridge;U. Chicago;U. Washington
中科院分区：
文献类型：
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作者：
D. Mortlock;H. Peiris;Zeljko Ivezic Imperial College London;U. Cambridge;U. Chicago;U. Washington
无需借助光谱，而是使用光度和天体测量来可靠地识别白矮星（WD），将其与主序星和类星体区分开来，是可能的。 WD 的颜色还可用于推断其内在属性（有效温度、表面重力等），但必须谨慎解释所获得的结果。困难源于立体角简并性的存在，正如对可能性的全面探索所揭示的那样，尽管如果使用简单的最佳拟合方法，这可以被掩盖。相反，如果采用贝叶斯方法，则可以打破这种简并性，因为这样就可以利用光谱拟合所暗示的有关 WD 表面重力的先验信息。当应用于异常值时，这种方法的好处尤其明显，例如 Vidrih 等人确定的候选光环和超冷 WD。对这些样本的重新分析证实了后一个样本的结果，但表明大多数光环候选者是光度噪声分布尾部的厚盘 WD。
It is possible to reliably identify white dwarfs (WDs) without recourse to spectra, instead using photometric and astrometric measurements to distinguish them from main-sequence stars and quasars. WDs' colours can also be used to infer their intrinsic properties (effective temperature, surface gravity, etc.), but the results obtained must be interpreted with care. The difficulties stem from the existence of a solid angle degeneracy, as revealed by a full exploration of the likelihood, although this can be masked if a simple best-fitting approach is used. Conversely, this degeneracy can be broken if a Bayesian approach is adopted, as it is then possible to utilize the prior information on the surface gravities of WDs implied by spectroscopic fitting. The benefits of such an approach are particularly strong when applied to outliers, such as the candidate halo and ultracool WDs identified by Vidrih et al. A reanalysis of these samples confirms their results for the latter sample, but suggests that most of the halo candidates are thick-disc WDs in the tails of the photometric noise distribution.