Table 1
CH3CN fitting results.
| Model | Component |  (1016 cm−2) |
Trot (K) | FWHM (km s−1) | Size (arcsec) | log(nH2) (cm−3) | VLSR (km s−1) |  |
|---|---|---|---|---|---|---|---|---|
| LTE model | – |  |
 |
 |
 |
– |  |
 |
| LTE two species | CH3CN |  |
 |
 |
 |
– |  |
25.2 (a) |
| CH313CN |  |
 |
 |
0.27* | – |  |
– | |
| LTE 2-comp | Extend |  |
 |
 |
 |
– |  |
 |
| Compact |  |
 |
 |
 |
– |  |
 |
|
| Non-LTE 2-comp | Extend |  |
 |
 |
 |
 |
 |
– |
| Compact |  |
 |
 |
 |
 |
 |
– | |
| Belloche et al. (2020) | – | 4 | 180 | 4.0(*) | 0.3(*) | – | – | – |
| Yang et al. (2021) | – |  |
150(c) | – | 0.5(*) | – | – | – |
Notes. (*)The parameter is fixed. (a)The value is derived from the CH3CN/CH313CN column density ratio. (b)The value is considered as a LTE case, because the posterior distribution reaches the upper boundary of 5 × 108 cm−3 in the MCMC modeling given a critical density of ~108 cm−3 for CH3CN J = 12–11, K = 0–7. (c)The fitting was done with a step of 50 K.
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