Constraining the distance to the North Polar Spur with Gaia DR2
Constraining the distance to the North Polar Spur with Gaia DR2
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DOI：
10.1093/mnras/staa2702
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发表时间：
2020-11-01
影响因子：
4.8
通讯作者：
Alves, Joao
中科院分区：
文献类型：
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作者：
Das, Kaustav K.;Zucker, Catherine;Alves, Joao
北极刺(NPS)是在射电和软X射线中观测到的银河系中最大的结构之一。虽然关于核动力源的起源已经做出了几种预测，但如果没有精确的距离限制，对该结构进行建模是困难的。在本文中，我们确定了到核动力源南端的准确距离，以及向高达55度的纬度的距离。首先，我们使用光学和近红外测光技术和GAIA数据发布2天文测量技术，对NPS的恒星距离和消光进行了拟合。我们对这些每颗恒星的距离-消光估计进行了建模，认为这是由未知距离的尘埃造成的，我们适合使用嵌套采样算法。然后，我们将消光与来自3D尘埃模型的杂散与XMM-牛顿X射线吸收和HI柱密度测量的综合独立测量进行比较。我们发现，我们可以占核动力源总柱密度的近100%，在纬度26度在140pC以内，在纬度700pC以内
The North Polar Spur (NPS) is one of the largest structures observed in the Milky Way in both the radio and soft X-rays. While several predictions have been made regarding the origin of the NPS, modelling the structure is difficult without precise distance constraints. In this paper, we determine accurate distances to the southern terminus of the NPS and towards latitudes ranging up to 55 degrees. First, we fit for the distance and extinction to stars towards the NPS using optical and near-infrared photometry and Gaia Data Release 2 astrometry. We model these per-star distance-extinction estimates as being caused by dust screens at unknown distances, which we fit for using a nested sampling algorithm. We then compare the extinction to the Spur derived from our 3D dust modelling with integrated independent measures from XMM-Newton X-ray absorption and H I column density measures. We find that we can account for nearly 100 per cent of the total column density of the NPS as lying within 140 pc for latitudes >26 degrees and within 700 pc for latitudes