Multi-generation massive star-formation in NGC 3576

Table 7:

Molecular constants $^{\alpha }$ .
Species	Transition	Frequency	$E_{\rm u}$ /k	$A_{\rm ul}$	$n_{\rm crit}~^{\beta}$
	(J_K)	(GHz)	(K)	(s^-1)	(cm^-3)
HCO⁺	$1\rightarrow0$	89.188526	4.280	$3.020\times 10^{-5}$	$3.0 \times 10^{5}$ $^{\dagger}$
H¹³CO⁺	$1\rightarrow0$	86.754330	4.160	2.800 $\times 10^{-5}$	$3.0 \times 10^{5}$ $^{\dagger}$
¹³CO	$1\rightarrow0$	110.210353	5.288	$6.389 \times 10^{-8}$	$6.5 \times 10^2$ $^{\dagger}$
C¹⁸O	$1\rightarrow0$	109.782173	5.267	4.961 $\times 10^{-7}$	-
CS	$2\rightarrow1$	97.980950	7.052	$1.703 \times 10^{-5}$	$2.0\times~10^5$
N₂H⁺	$1_{1}\rightarrow0_{1}$	93.171880	4.471	$3.654 \times 10^{-5}$	$2 \times 10^{5}$ ^un
	$1_{2}\rightarrow0_{1}$	93.173700	-	-	-
	$1_{0}\rightarrow0_{1}$	93.176130	-	-	-
NH₃	$1_{1}\rightarrow1^{\prime}_{1^{\prime}}$	23.694480	17.215	$1.67\times 10^{-7}$	$2\times 10^{4}$ ^sw
	$2_{2}\rightarrow2^{\prime}_{~2^{\prime}}$	23.722630	63.866	2.29 $\times 10^{-7}$

$^{\alpha }$ Unless otherwise noted, all values quoted here are sourced from the NASA Jet Propulsion Lab (JPL) spectral line database (Pickett, et al. 1998); $^{\beta}$ Critical density values marked with a $\dagger$ are calculated from the formula ${n_{\rm crit} = A_{\rm ul}/\gamma_{_{H_2}}}$ , where ${\rm\gamma_{_{\rm H_2}}}$ is the ``standard'' collisional rate coefficient for H₂, assumed equal to 10¹⁰ ${\rm cm^3.s^{-1}.H_2}$ - ${\rm molecules^{-1}}$ . Other values are referenced as follows: ^un Ungerechts et al. (1997), ^sw Swade (1989).

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