arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1809.08261astro-ph.EPastro-ph.IM
收藏

系外行星直接探测和探测不到的贝叶斯框架

A Bayesian Framework for Exoplanet Direct Detection and Non-Detection

Jean-Baptiste Ruffio, Dimitri Mawet, Ian Czekala, Bruce Macintosh, Robert J. De Rosa, Garreth Ruane, Michael Bottom, Laurent Pueyo, Jason J. Wang, Lea Hirsch, Z… 展开作者

Jean-Baptiste Ruffio, Dimitri Mawet, Ian Czekala, Bruce Macintosh, Robert J. De Rosa, Garreth Ruane, Michael Bottom, Laurent Pueyo, Jason J. Wang, Lea Hirsch, Zhaohuan Zhu, Eric L. Nielsen

摘要:

严格量化高对比度成像数据中的信息对于告知后续策略以确认点源的亚恒星性质、约束行星-盘相互作用的理论模型以及推导行星发生率是重要的。然而,在系外行星直接成像社区内,几乎完全使用频率论检测阈值(即对比度曲线)和相关完整性来定义未检测。当包含在贝叶斯框架中时,这可能导致概念上的不一致。贝叶斯上限是指参数的真实值以一定概率低于此上限。相关概率是后验分布的积分,上限为上限。总之,频率论上限是关于行星可探测性的陈述,而贝叶斯上限是关于给定数据的参数位于区间内的概率的陈述。因此,后者更适合于拒绝基于其预测的假设或理论模型。在这项工作中,我们强调,贝叶斯统计和上限更容易解释,通常比频率论的方法更具约束力。我们说明了使用贝叶斯分析在两种不同的情况下:1)与一个已知的行星位置,我们还建议使用模型比较,以约束天体物理性质的点源和2)间隙雕刻的行星在TW Hya。最后,我们还提到了径向速度和直接成像观测相结合的问题。

英文摘要:

Rigorously quantifying the information in high contrast imaging data is important for informing follow-up strategies to confirm the substellar nature of a point source, constraining theoretical models of planet-disk interactions, and deriving planet occurrence rates. However, within the exoplanet direct imaging community, non-detections have almost exclusively been defined using a frequentist detection threshold (i.e. contrast curve) and associated completeness. This can lead to conceptual inconsistencies when included in a Bayesian framework. A Bayesian upper limit is such that the true value of a parameter lies below this limit with a certain probability. The associated probability is the integral of the posterior distribution with the upper limit as the upper bound. In summary, a frequentist upper limit is a statement about the detectability of planets while a Bayesian upper limit is a statement about the probability of a parameter to lie in an interval given the data. The latter is therefore better suited for rejecting hypotheses or theoretical models based on their predictions. In this work we emphasize that Bayesian statistics and upper limits are more easily interpreted and typically more constraining than the frequentist approach. We illustrate the use of Bayesian analysis in two different cases: 1) with a known planet location where we also propose to use model comparison to constrain the astrophysical nature of the point source and 2) gap-carving planets in TW Hya. To finish, we also mention the problem of combining radial velocity and direct imaging observations.

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。

↑