论文标题
发现与北极刺和环I相关的非平衡电离等离子体
Discovery of non-equilibrium ionization plasma associated with the North Polar Spur and Loop I
论文作者
论文摘要
我们使用档案$ Suzaku $ Data研究了North Polar Spur（NPS）/Loop I的详细等离子体条件。在先前的研究中，X射线等离子体状态已假定碰撞电离平衡（CIE），但我们还假设非平衡电离电离（NEI）更详细地检查血浆条件。 We found that most of the plasma in the NPS/Loop I favors the state of NEI, and has the density-weighted ionization timescale of $n_e t\sim10^{11-12}$ s cm$^{-3}$ and the electron number density $n_e\sim$ a few $\times$ 10$^{-3}$ cm$^{-3}$.对于NPS/LOOP I，估计冲击阵线通过等离子体后的等离子冲击年龄，$ t $或冲击阵线通过等离子体的时间经过的时间，该顺序为几美元{myr} $，这使整个NPS/Loop I结构的年龄限制了严格的下限。我们发现，与CIE假设相比，NEI导致温度明显更高，排放度量较低。 NEI下的电子温度估计高达0.5 keV，朝着$δθ= -20^\ Circ $的最明亮的X射线NPS脊，在$ -10^\ Circ $下降到0.3 keV，并且再次增加到$ \ sim 0.6 $ 0.6 $ kev，倾向于$δ\ sim0^sim0^sim0^sim0^sim0^sim0^sim0^sim0^sim0^sim0^sim0^sim0^sim0^sim0^cirs，大约是circir cirs yous of sim0^sim circ。在这里，$δθ$是距环路外边缘的角度距离。我们讨论了在天体物理现象中引入NEI对等离子体状态研究的含义。
We investigated the detailed plasma condition of the North Polar Spur (NPS)/Loop I using archival $Suzaku$ data. In previous research collisional ionization equilibrium (CIE) have been assumed for X-ray plasma state, but we also assume non-equilibrium ionization (NEI) to check the plasma condition in more detail. We found that most of the plasma in the NPS/Loop I favors the state of NEI, and has the density-weighted ionization timescale of $n_e t\sim10^{11-12}$ s cm$^{-3}$ and the electron number density $n_e\sim$ a few $\times$ 10$^{-3}$ cm$^{-3}$. The plasma shock age, $t$, or the time elapsed after the shock front passed through the plasma, is estimated to be on the order of a few $\rm{Myr}$ for the NPS/Loop I, which puts a strict lower limit to the age of the whole NPS/Loop I structure. We found that NEI results in significantly higher temperature and lower emission measure than those currently derived under CIE assumption. The electron temperature under NEI is estimated to be as high as 0.5 keV toward the brightest X-ray NPS ridge at $Δθ=-20^\circ$, which decreases to 0.3 keV at $-10^\circ$, and again increases to $\sim 0.6$ keV towards the outer edge of Loop I at $Δθ\sim0^\circ$, about twice the currently estimated temperatures. Here, $Δθ$ is the angular distance from the outer edge of Loop I. We discuss the implication of introducing NEI for the research in plasma states in astrophysical phenomena.
