A Word to the WISE: Confusion is Unavoidable for WISE-selected Infrared Excesses
A Word to the WISE: Confusion is Unavoidable for WISE-selected Infrared Excesses
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DOI：
10.3847/1538-4357/ab7249
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发表时间：
2020-02
期刊：
影响因子：
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通讯作者：
E. Dennihy;J. Farihi;N. G. Fusillo;J. Debes
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文献类型：
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作者：
E. Dennihy;J. Farihi;N. G. Fusillo;J. Debes
具有来自星周尘埃的过量红外辐射的恒星对于研究系外行星系统是非常宝贵的，为我们了解行星形成和毁灭的过程提供了信息。全天空光度测量已经使尘埃红外过量候选者的识别变得微不足道，然而，依赖于Wise Infrared Survey Explorer（WISE）数据的样本受到源混淆的困扰，导致高假阳性率。限制其对WISE选择的样品的贡献的技术已经开发出来，随着我们接近斯皮策的寿命结束，它们的有效性变得更加重要，斯皮策是唯一能够确认过量的设施。在这里，我们提出了一个斯皮策后续的一个样本的22个WISE选择的红外过量候选人附近的WISE检测限的弱端。22个超标中有8个被认为是来源混淆的结果，其余的候选者都被斯皮策数据证实。我们认为，地面近红外成像和天体测量过滤的样本，以限制样本之间的混淆的功效。我们发现，这两种技术都是值得审查的候选人，但未能确定所有的混乱过剩，这表明它们不能用来确认明智的选择红外过剩的候选人，但只能排除它们。这一结果证实了WISE选择的红外过量样品总是受到明显污染的预期，并且无论应用何种过滤器，在解释时都应小心。
Stars with excess infrared radiation from circumstellar dust are invaluable for studies of exoplanetary systems, informing our understanding of processes of planet formation and destruction alike. All-sky photometric surveys have made the identification of dusty infrared excess candidates trivial, however, samples that rely on data from Wise Infrared Survey Explorer (WISE) are plagued with source confusion, leading to high false-positive rates. Techniques to limit its contribution to WISE-selected samples have been developed, and their effectiveness is even more important as we near the end-of-life of Spitzer, the only facility capable of confirming the excess. Here, we present a Spitzer follow-up of a sample of 22 WISE-selected infrared excess candidates near the faint-end of the WISE detection limits. Eight of the 22 excesses are deemed the result of source confusion, with the remaining candidates all confirmed by the Spitzer data. We consider the efficacy of ground-based near-infrared imaging and astrometric filtering of samples to limit confusion among the sample. We find that both techniques are worthwhile for vetting candidates, but fail to identify all of the confused excesses, indicating that they cannot be used to confirm WISE-selected infrared excess candidates, but only to rule them out. This result confirms the expectation that WISE-selected infrared excess samples will always suffer from appreciable levels of contamination, and that care should be taken in their interpretation regardless of the filters applied.