Abstract

The collisional pumping of OH masers in non-dissociative C-type shocks near supernova remnants is considered. The emergence of maser emission in OH lines is investigated for various shock parameters—the shock speed, the preshock gas density, the cosmic-ray ionization rate, and the magnetic field strength. The largest optical depth in the 1720 MHz line is reached at high gas ionization rates \(\zeta\geq 10^{-15}\) s\({}^{-1}\), an initial density \(n_{\textrm{H,0}}\leq 2\times 10^{4}\) cm\({}^{-3}\), and a shock speed \(u_{\textrm{s}}\geq 20\) km s\({}^{-1}\). According to our calculations, there is also a level population inversion for the 6049 and 4765 MHz transitions of excited OH rotational states. However, the optical depth in these lines is small for all of the investigated shock parameters, which explains the non-detection of maser emission in these lines in supernova remnants.

中文翻译：

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超新星残骸附近的OH Masers的集体泵吸

摘要

在超新星残骸附近的非解离性C型激波中，OH激射的碰撞泵被考虑。针对各种冲击参数（冲击速度，预冲击气体密度，宇宙射线电离率和磁场强度）研究了OH线中maser发射的出现。在高气体电离速率\（\ zeta \ geq 10 ^ {-15} \） s \（{} ^ {-1} \），初始密度\（n_ { \ textrm {H，0}} \ leq 2 \ times 10 ^ {4} \） cm \ {{} ^ {-3} \）和冲击速度\（u _ {\ textrm {s}} \ geq 20 \）公里s \（{} ^ {-1} \）。根据我们的计算，激发的OH旋转状态的6049和4765 MHz跃迁也存在一定的种群反转。但是，对于所有调查的冲击参数，这些谱线中的光学深度都较小，这解释了在超新星遗迹中未检测到这些谱线中的大量发射。