We present the results of numerically solving the rate equations for the first 31 rotational states of CS in the ground vibrational state to determine the conditions under which the J = 1 - 0, J = 2 - 1, and J = 3 - 2 transitions are inverted to produce maser emission. The essence of our results is that the CS(v=0) masers are collisionally pumped and that, depending on the spectral energy distribution, dust emission can suppress the masers. Apart from the J = 1 - 0 and J = 2 - 1 masers, the calculations also show that the J = 3 - 2 transition can be inverted to produce maser emission. It is found that beaming is necessary to explain the observed brightness temperatures of the recently discovered CS masers in W51 e2e. The model calculations suggest that a CS abundance of a few times 10-5 and CS(v=0) column densities of the order of 1016 cm-2 are required for these masers. The rarity of the CS masers in high-mass star-forming regions might be the result of a required high CS abundance as well as due to attenuation of the maser emission inside as well as outside of the hot core.

On the pumping of the CS(=0) masers in W51 e2e

Goddi C.
2021-01-01

Abstract

We present the results of numerically solving the rate equations for the first 31 rotational states of CS in the ground vibrational state to determine the conditions under which the J = 1 - 0, J = 2 - 1, and J = 3 - 2 transitions are inverted to produce maser emission. The essence of our results is that the CS(v=0) masers are collisionally pumped and that, depending on the spectral energy distribution, dust emission can suppress the masers. Apart from the J = 1 - 0 and J = 2 - 1 masers, the calculations also show that the J = 3 - 2 transition can be inverted to produce maser emission. It is found that beaming is necessary to explain the observed brightness temperatures of the recently discovered CS masers in W51 e2e. The model calculations suggest that a CS abundance of a few times 10-5 and CS(v=0) column densities of the order of 1016 cm-2 are required for these masers. The rarity of the CS masers in high-mass star-forming regions might be the result of a required high CS abundance as well as due to attenuation of the maser emission inside as well as outside of the hot core.
2021
masers
methods: numerical
stars: Formation
stars: Massive
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11584/346113
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 0
social impact