标题： NuSTAR 观测 Norma 臂的初步结果 显示英文标题

标题： Initial Results from NuSTAR Observations of the Norma Arm

摘要： 结果展示了使用聚焦式硬X射线望远镜NuSTAR对Norma旋臂进行的初步调查结果。该调查覆盖了0.2平方度$^2$的天空区域，在3-79千电子伏能段内，最小和最大原始观测深度分别为15千秒和135千秒。除了爆发中的明亮黑洞X射线双星（4U 1630-47）和一个新的X射线暂现源（NuSTAR J163433-473841）外，NuSTAR还定位了Chandra对该区域调查中的三个源，其光谱首次延伸至超过10千电子伏：CXOU J163329.5-473332、CXOU J163350.9-474638和CXOU J163355.1-473804。通过对宽广X射线范围（0.3-79千电子伏）的成像、时变和光谱数据进行分析与解释，旨在对这些目标进行分类。CXOU J163329.5-473332要么是一个激变变星，要么是一个微弱的低质量X射线双星。CXOU J163350.9-474638在长年时间尺度上强度变化，并且由于没有多波段对应体，它可能是一个遥远的X射线双星或者可能是磁星。CXOU J163355.1-473804在6.7千电子伏处具有氦-like铁线，被归类为附近的激变变星。计划对Norma旋臂和银河系中心进行更多调查，而这些NuSTAR观测将从本试点研究中学到的经验中受益。 显示英文摘要

摘要： Results are presented for an initial survey of the Norma Arm gathered with the focusing hard X-ray telescope NuSTAR. The survey covers 0.2 deg$^2$ of sky area in the 3-79 keV range with a minimum and maximum raw depth of 15 ks and 135 ks, respectively. Besides a bright black-hole X-ray binary in outburst (4U 1630-47) and a new X-ray transient (NuSTAR J163433-473841), NuSTAR locates three sources from the Chandra survey of this region whose spectra are extended above 10 keV for the first time: CXOU J163329.5-473332, CXOU J163350.9-474638, and CXOU J163355.1-473804. Imaging, timing, and spectral data from a broad X-ray range (0.3-79 keV) are analyzed and interpreted with the aim of classifying these objects. CXOU J163329.5-473332 is either a cataclysmic variable or a faint low-mass X-ray binary. CXOU J163350.9-474638 varies in intensity on year-long timescales, and with no multi-wavelength counterpart, it could be a distant X-ray binary or possibly a magnetar. CXOU J163355.1-473804 features a helium-like iron line at 6.7 keV and is classified as a nearby cataclysmic variable. Additional surveys are planned for the Norma Arm and Galactic Center, and those NuSTAR observations will benefit from the lessons learned during this pilot study.