We carry out axisymmetric two-dimensional radiation hydrodynamical simulations of super-critical accretion columns on to strongly magnetized neutron stars. The effect of the strong magnetic field is taken into account by inhibiting the fluid motion across the radial magnetic field of the neutron stars. It is found that the high-density matter falls on to the neutron star along the sidewall of the column. Within the column, two high-density inflow regions shaped like a hollow cone are found for the case of extremely high mass accretion rates, |${\dot{M}}/(L_{\rm Edd}/c{\,}^2) \sim 5\times 10^{2}$|⁠, where |$\dot{M}$|⁠, |$L_{\rm Edd}$|⁠, and |$c$| are the mass accretion rate on to the neutron star, the Eddington luminosity, and the speed of light, respectively. The less dense matter in the gap between the high density inflow regions is blown away via the radiative force. The resultant structure of the inflow looks like a triple hollow cone. Matter falls on to the neutron star only through the sidewall for the case of moderately high mass accretion rates, |${\dot{M}}/(L_{\rm Edd}/c{\,}^2)\, {\sim 3 \times 10^1}$|⁠. A low-density outflow fills the interior of the column. In this case, the inflow structure looks like a single hollow cone. Although the copious photons are generated in the inflow regions via a shock, the photons escape from the sidewall of the column and the radiation force does not prevent inflow. The resulting luminosity of the sidewall exceeds |$\sim\! 30$| times the Eddington luminosity for neutron stars, which is consistent with the observed luminosity of ultra-luminous X-ray pulsars.

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ULX脉冲星中强磁中子星上的超临界柱积聚

我们对强磁化中子星进行超临界吸积柱的轴对称二维辐射流体动力学模拟。通过抑制流体在中子星径向磁场上的运动来考虑强磁场的影响。发现高密度物质沿着柱子的侧壁落在中子星上。在极高的质量吸积率|| $ {\ dot {M}} /（L _ {\ rm Edd} / c {\，}的情况下，在色谱柱内发现了两个形状像空心圆锥体的高密度流入区域。^ 2）\ sim 5 \ times 10 ^ {2} $ |⁠，其中| $ \ dot {M} $ |⁠，| $ L _ {\ rm Edd} $ |⁠和| $ c $ |分别是中子星的质量吸积率，爱丁顿光度和光速。高密度流入区域之间的间隙中密度较小的物质通过辐射力被吹走。流入的最终结构看起来像一个三重空心锥。对于质量吸纳率较高的情况，| $ {\ dot {M}} /（L _ {\ rm Edd} / c {\，} ^ 2）\，{ \ sim 3 \ times 10 ^ 1} $ |⁠。低密度流出物填充了色谱柱的内部。在这种情况下，流入结构看起来像单个空心锥。尽管大量光子是通过冲击在流入区域中生成的，但光子会从色谱柱的侧壁逸出，并且辐射力无法阻止流入。侧壁的最终亮度超过| $ \ sim \ !！30 $ | 乘以中子星的爱丁顿光度，这与观测到的超发光X射线脉冲星的光度一致。