不过现在NASA的雨燕卫星在硬（高能）X射线的巡天新成果可靠地显示活动星系核与星系合并的紧密联系。
New results from a premier sky survey by NASA's Swift satellite at hard (energetic) X-ray energies now solidly show a strong association of AGN with merging galaxies, though.
西斯特纳斯指出：在星系的黑洞中，对于X射线活动强烈脉冲的开启过程，现在还不大了解。
Processes that switch on immense pulses of x-ray-generating activity in a galactic black hole aren't well understood, Cisternas notes.
平均每个美国人每年接收360毫雷姆的射线，其中300毫雷姆来自自然放射源，60毫雷姆来自人类活动(雷姆是射线强度单位)。
The average American receives 360millirems of radiation each year, 300 from natural sources and 60 from man-made activities. (a rem is a unit of radiation exposure.)
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