标题： 解析的原子线揭示了两个超亮X射线源中的外流 显示英文标题

标题： Resolved atomic lines reveal outflows in two ultraluminous X-ray sources

摘要： 超亮X射线源是星系中的河外、非核心点源，其X射线光度高于3x10^39 erg/s，被认为是由致密天体吸积驱动的。可能的解释包括强磁场中子星的吸积、质量小于20 Msolar的恒星级黑洞（在或超过经典爱丁顿极限）或质量为10^3-5 Msolar的中等质量黑洞。以往分析中能量分辨率不足，迄今为止阻碍了对X射线波段中任何发射或吸收线的明确识别，从而阻止了对吸积流的详细分析。在此，我们报告在超亮X射线源NGC 1313 X-1的高分辨率X射线光谱中存在来自高度电离铁、氧和氖的X射线发射线，累积显著性大于5 sigma，并且存在蓝移（约0.2c）的吸收线（5 sigma）。在类似的源NGC 5408 X-1中，我们也检测到静止的发射线和蓝移的吸收线。蓝移的吸收线必须发生在快速流出气体中，而发射线则来源于源周围的慢速运动气体。我们得出结论，致密天体被强大的风包围，流出速度约为0.2c，这与吸积超大质量黑洞和超吸积恒星级黑洞模型的预测一致。 显示英文摘要

摘要： Ultraluminous X-ray sources are extragalactic, off-nucleus, point sources in galaxies with an X-ray luminosity above 3x10^39 erg/s, thought to be powered by accretion onto a compact object. Possible explanations include accretion onto neutron stars with strong magnetic fields, stellar-mass black holes (< 20 Msolar) at or in excess of the classical Eddington limit or intermediate-mass black holes (10^3-5 Msolar). The lack of sufficient energy resolution in previous analyses has hitherto prevented an unambiguous identification of any emission or absorption lines in the X-ray band, thereby precluding a detailed analysis of the accretion flow. Here we report the presence of X-ray emission lines arising from highly ionized iron, oxygen and neon with a cumulative significance > 5 sigma, and blueshifted (~0.2c) absorption lines (5 sigma) in the high-resolution X-ray spectrum of the ultraluminous X-ray source NGC 1313 X-1. In a similar source, NGC 5408 X-1, we also detect emission lines at rest and blueshifted absorption. The blueshifted absorption lines must occur in a fast outflowing gas, whereas the emission lines originate in slow-moving gas around the source. We conclude that the compact object is surrounded by powerful winds with an outflow velocity of about 0.2c as predicted by models of accreting supermassive black holes and hyper-accreting stellar mass black holes.