Simulating the Sensitivity to Stellar Point Sources of Chandra X-Ray Observations
Simulating the Sensitivity to Stellar Point Sources of Chandra X-Ray Observations
复制标题
模拟钱德拉 X 射线观测对恒星点源的敏感性
DOI：
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发表时间：
2015
影响因子：
8.7
通讯作者：
A. Zezas
中科院分区：
文献类型：
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作者：
N. Wright;J. Drake;M. Guarcello;V. Kashyap;A. Zezas
钱德拉天鹅座OB2遗产调查是对附近巨大的天鹅座OB2协会进行的广泛而深入的X射线调查。这次巡天探测到了约8000个X射线源，其中大部分是星协中的前主序星。为了便于对这些来源以及潜在的OB关联进行定量科学研究，重要的是要了解观测的敏感性和观测的完整性水平。在这里，我们描述了使用分层蒙特卡罗模拟，以实现这一目标相结合的观测，源验证过程的分析估计，和一组广泛的源检测模拟的经验性质。我们发现，我们的调查达到了90%的完整性水平的前主序人口在天鹅座OB2的距离，在X射线光度为4 × 1030 erg s−1和恒星质量为1.3兆质量的随机分布的人口。对于空间聚集的人群，如天鹅座OB2，90%的完整性水平是在1.1百万光年处达到的，因为源更集中在我们调查的高暴露区域。这些模拟可以很容易地适用于其他X射线观测和调查，我们提供了X射线探测效率曲线的一个非常广泛的阵列的源和背景属性，使这些模拟可以很容易地利用其他用户。
The Chandra Cygnus OB2 Legacy Survey is a wide and deep X-ray survey of the nearby and massive Cygnus OB2 association. The survey has detected ∼8000 X-ray sources, the majority of which are pre-main-sequence X-ray-emitting young stars in the association itself. To facilitate quantitative scientific studies of these sources, as well as the underlying OB association, it is important to understand the sensitivity of the observations and the level of completeness the observations have obtained. Here we describe the use of a hierarchical Monte Carlo simulation to achieve this goal by combining the empirical properties of the observations, analytic estimates of the source verification process, and an extensive set of source detection simulations. We find that our survey reaches a 90% completeness level for a pre-main-sequence population at the distance of Cyg OB2 at an X-ray luminosity of 4 × 1030 erg s−1 and a stellar mass of 1.3 M ⊙ for a randomly distributed population. For a spatially clustered population such as Cyg OB2 the 90% completeness level is reached at 1.1 M ⊙ instead, as the sources are more concentrated in areas of our survey with a high exposure. These simulations can easily be adapted for use with other X-ray observations and surveys, and we provide X-ray detection efficiency curves for a very wide array of source and background properties to allow these simulations to be easily exploited by other users.