Modelling cosmic masers in C-type shock waves – the coexistence of Class I CH3OH and 1720 MHz OH masers

The collisional pumping of CH3OH and OH masers in non-dissociative C-type shock waves is studied. chemical processes responsible for the evolution molecule abundances wave are considered detail. large velocity gradient approximation used to model radiative transfer molecular lines. We present calculations optical depth maser transitions a grid models that vary cosmic ray ionization rate, gas density speed. show pre-shock densities $n_{H,tot} = 2 \times 10^4-2 10^5$ cm$^{-3}$ optimal methanol transitions. A complete dissociation at front takes place speeds $u_{s} \gtrsim 25$ km s$^{-1}$. At high 10^{6}$ cm$^{-3}$, just above threshold speed \approx 15-17.5$ s$^{-1}$ corresponding sputtering icy mantles dust grains. transition E $4_{-1} \to 3_0$ 36.2 GHz has higher than A$^+$ $7_0 6_1$ 44.1 rate $\zeta_{H_2} 10^{-15}$ 10^4$ cm$^{-3}$. These results can be applied interpretation observational data on near supernova remnants clouds Central Molecular Zone. same time, necessary condition operation 1720 MHz gas, find physical conditions conducive both hydroxyl 10^{-15} - 3 s$^{-1}$, narrow range speeds.