SS433 is the only Galactic binary system known to persistently accrete at highly super-critical (or hyper-critical) rates, similar to those in tidal disruption events, and likely needed to explain the rapid growth of those very high redshift quasars containing massive SMBHs. Probing the inner regions of SS433 in the X-rays is crucial to understanding this system, and super-critical accretion in general, but is highly challenging due to obscuration by the surrounding wind, driven from the accretion flow. NuSTAR observed SS433 in the hard X-ray band across multiple phases of its 162 d superorbital precession period. Spectral-timing tools allow us to infer that the hard X-ray emission from the inner regions is likely being scattered towards us by the walls of the wind-cone. By comparing to numerical models, we determine an intrinsic X-ray luminosity of ≥ 2 × 1037 erg s−1 and that, if viewed face on, we would infer an apparent luminosity of >1 × 1039 erg s−1, confirming SS433’s long-suspected nature as an ultraluminous X-ray source (ULX). We present the discovery of a narrow, ∼100 s lag due to atomic processes occurring in outflowing material travelling at least 0.14–0.29c, which matches absorption lines seen in ULXs and – in the future – will allow us to map a super-critical outflow for the first time.

中文翻译：

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NuSTAR 揭示了 SS433 的隐藏本质

SS433 是已知的唯一一个以高度超临界（或超临界）速率持续吸积的银河双星系统，类似于潮汐破坏事件中的那些，并且可能需要解释那些包含大量 SMBH 的非常高的红移类星体的快速增长。在 X 射线中探测 SS433 的内部区域对于理解该系统以及一般的超临界吸积至关重要，但由于吸积流驱动的周围风的遮挡，具有高度挑战性。NuSTAR 在其 162 天超轨道进动周期的多个阶段的硬 X 射线波段中观察到 SS433。光谱计时工具使我们能够推断出来自内部区域的硬 X 射线发射很可能被风锥的壁向我们散射。通过比较数值模型，我们确定了 ≥ 2 × 1037 erg s-1 的内在 X 射线光度，如果正面观察，我们将推断出 > 1 × 1039 erg s-1 的表观光度，证实了 SS433 长期以来被怀疑的性质超发光 X 射线源 (ULX)。我们发现了一个狭窄的 ∼100 s 滞后，这是由于流出材料中发生的原子过程发生在至少 0.14-0.29c 之间，这与 ULX 中看到的吸收线相匹配，并且 - 在未来 - 将使我们能够绘制超临界第一次流出。