**Table 2:** Observed line ratios^a.
Species	Transitions	Line ratio
CO	2-1/1-0	0.43
HCO⁺	3-2/1-0	0.42
HNC	3-2/1-0	0.75
HCN	3-2/1-0	0.22^b
CN	2-1/1-0	0.31-0.56^c
H₂CO	3(1, 2)-2(1, 1)/2(1, 2)-1(1, 1)	0.31
HC₃N	16-15/10-9	0.91^d
HC₃N	25-24/10-9	0.47

^a If $\theta_{\rm s}$ is the Gaussian source size (assumed to be 2 $\hbox{$^{\prime\prime}$ }$ (see Sect. 2.1)), and $\theta_{\rm b}$ is the beam size for the line, the ratio of integrated intensities for transition X and Y, corrected for beam and source-size, is assumed to scale according to $R~ = ~{ \int T_{\rm mb}^*(X) {\rm d}V ~ (\theta_{\rm b}^2(X) + \theta_{\rm s}^... ...ver \int T_{\rm mb}^*(Y) {\rm d}V ~ (\theta_{\rm b}^2(Y) + \theta_{\rm s}^2) }$ . Errors in line ratios are $\approx$ 20% including rms and calibration errors. ^b We used the interferometric line ratio between HCN and HCO⁺ 1-0 measured by Imanishi et al. (2004) to scale our observed HCO⁺ 1-0 line into an expected HCN 1-0 intensity (see Sect. 2.1). ^c Integrated intensity ratio is 0.56 (too high due to the missing CN 1-0 emission) and the peak-to-peak is 0.31 (see Sect. 2.1). ^d The line ratio is somewhat uncertain due to para-H₂CO contamination (see Sect. 2.1).

Source LaTeX | All tables | In the text