 Optically thin CO rotational thermometry

ID: optically-thin-co-rotational-thermometry

For one optically thin LTE carbon-monoxide component,

L_{u l} = N_{u} A_{u l} h ν_{u l}

and

N_{J} \propto (2 J + 1) e^{- E_{J} / (k_{B} T)}

. Thus

C = 7 A_{32} ν_{32} / (3 A_{10} ν_{10})

for the 3–2/1–0 luminosity ratio. The temperature then determines the

J = 1

population fraction and hence the CO mass. Multiple excitation components, optical depth or subthermal excitation invalidate a single-temperature inference.

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