论文标题
3-20 KEV能量带中宇宙X射线背景的Nustar测量
NuSTAR measurement of the cosmic X-ray background in the 3-20 keV energy band
论文作者
论文摘要
我们介绍了宇宙X射线背景（CXB）的强度，其中Nustar望远镜在3-20 KEV能量范围内。我们的方法通过望远镜的侧孔对Nustar检测器上的CXB信号进行空间调制。基于总暴露于7 ms的选定外乳缘场的NUSTAR观察结果，我们估计CXB 3-20 KEV通量为2.8e-11 ERG/S/CM^2/deg^2，比与Heao-1测得的〜8高约8，并且与积分测量一致。 3-20 KEV能带中推断的CXB光谱形状与Gruber等人的规范模型一致。我们证明，由Nustar测得的空间调制的CXB信号不会受到系统噪声的污染，并且受到光子统计的限制。不同天空方向之间CXB强度的相对散射与宇宙方差兼容，这为研究CXB各向异性的新可能性与Nustar一起研究。
We present measurements of the intensity of the Cosmic X-ray Background (CXB) with the NuSTAR telescope in the 3-20 keV energy range. Our method uses spatial modulation of the CXB signal on the NuSTAR detectors through the telescope's side aperture. Based on the NuSTAR observations of selected extragalactic fields with a total exposure of 7 Ms, we have estimated the CXB 3-20 keV flux to be 2.8E-11 erg/s/cm^2/deg^2, which is ~8 higher than measured with HEAO-1 and consistent with the INTEGRAL measurement. The inferred CXB spectral shape in the 3-20 keV energy band is consistent with the canonical model of Gruber et al. We demonstrate that the spatially modulated CXB signal measured by NuSTAR is not contaminated by systematic noise and is limited by photon statistics. The measured relative scatter of the CXB intensity between different sky directions is compatible with cosmic variance, which opens new possibilities for studying CXB anisotropy over the whole sky with NuSTAR.
