Discovery of non-equilibrium ionization plasma associated with the North Polar Spur and Loop I

ABSTRACT We investigated the detailed plasma condition of North Polar Spur (NPS)/Loop I using archival Suzaku data. In previous research, collisional ionization equilibrium (CIE) have been assumed for X-ray state, but we also assume non-equilibrium (NEI) to check in more detail. found that most NPS/Loop favors state NEI, and has density-weighted timescale net ∼ 1011–12 s cm−3 electron number density ne a few × 10−3 cm−3. The shock age, t, or time elapsed after front passed through plasma, is estimated be on order $\rm {Myr}$ I, which puts strict lower limit age whole structure. NEI results significantly higher temperature emission measure than those currently derived under CIE assumption. as high 0.5 keV toward brightest NPS ridge at Δθ = −20○, decreases 0.3 −10○, again increases ∼0.6 towards outer edge Loop 0○, about twice temperatures. Here, angular distance from I. discuss implication introducing research states astrophysical phenomena.