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Table 4

Isocyanide column densities and N(X-NC)/N(X-CN) ratios.

Orion KLd Orion KL Orion KL Orion KL Sgr B2
(IRAM 30m) (ALMA SV) (ALMA SV) (ALMA SV) (IRAM 30m)
EtCN3 EtCN1 EtCN2
Coordinates
(J2000.0)
HPBWa [″] 30–8 ~1.9 × 1.4 ~1.9 × 1.4 ~1.9 × 1.4 30–21
Frequencyb [GHz] 80–307 213.7–246.7 213.7–246.7 213.7–246.7 80–115.5
N(CH3NC) [cm−2] (6.0 ± 3.0) ×1013 (1.2 ± 0.4) × 1014 ≤(1.0 ± 0.5) × 1014 (6.0 ± 2.0) × 1013 (3.2 ± 0.5) × 1016
N(CH3CH2NC) [cm−2] ≤(2.0 ± 1.0) × 1014 ≤(1.5 ± 0.7) × 1014 ≤(2.0 ± 1.0) × 1014 ≤(2.0 ± 1.0) × 1014 ≤(1.5 ± 0.5) × 1016
N(CH2CHNC) [cm−2] ≤(4.0 ± 2.0) × 1014 ≤(2.5 ± 1.0) × 1014 ≤(2.0 ± 1.0) × 1014 ≤(2.0 ± 1.0) × 1014 ≤(1.5 ± 0.5) × 1016
Rc (Methyl) 0.002 0.003e ≤0.0014h 0.0006h 0.01k
Rc (Ethyl) ≤0.003 ≤0.0025f ≤0.007h ≤0.007h ≤0.003k
Rc (Vinyl) ≤0.1 ≤0.025g ≤0.02i ≤0.05j ≤0.02k

Notes. (a) HPBW (half power beam width) for observations with single dish telescope (IRAM 30m) and synthetic beam for the ALMA SV observations. (b) Range of frequencies considered in the analysis. (c) R = N(X-NC)/N(X-CN), where X = methyl, ethyl, vinyl. (d) From López et al. (2014). (e) N(CH3CN) = (4.0 ± 1.0) × 1016 cm−2 for EtCN3 assuming a 12C/13C ratio of 45 (Tercero et al. 2010). (f) N(CH3 CH2CN) = (6.0 ± 2.0) × 1016 cm−2 for EtCN3 by modeling the CH3 CH2CN b-type lines (optically thin). (g) N(CH2CHCN) = (1.0 ± 0.3) × 1016 cm−2 for EtCN3. (h) CH3 CN and CH3 CH2CN column densities for EtCN1 and EtCN2 (Positions A and B) from Cernicharo et al. (2016). (i) N(CH2CHCN) = (1.0 ± 0.3) × 1016 cm−2 for EtCN1. (j) N(CH2CHCN) = (4.0 ± 1.0) × 1015 cm−2 for EtCN2. (k) CH3 CN, CH3 CH2CN, and CH2 CHCN column densities for Sgr B2 (N) from Belloche et al. (2013).

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