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Table 2

Resulting NH+ and NH column densities, N, column density ratios with related species, and abundances, X, with respect to the total amount of hydrogen towards Sgr B2 (M) and G10.60.6.

Line-of-sighta
Source V LSR N(NH+) b c N(p-NH b c X(NH+) X(p-NH
(km s-1) (cm-2) (%) (%) (%) (cm-2) (%) (%)

Sgr B2 (M) 140-27 ≲1.7 × 1012 ≲0.1 ≲0.2 ≲0.2 ≲9.9 × 1011 0.1 0.1 ≲4 × 10-11 d ≲2 × 10-11 d
G10.60.6 10-55 ≲1.6 × 1012 ≲0.9 ≲1.5 ≲1.9 ≲2.2 × 1012 ≲1.9 ≲2.6 ≲3 × 10-11 e ≲4 × 10-11 e

Source molecular cloud/envelope
Sgr B2 (M) 57–68 ≲9.1 × 1011 ... ... ... ≲4.0 × 1011 ... ... ≲2 × 10-12 f ≲8 × 10-13 f
G10.60.6 3 ≲2.8 × 1012 ... ... ... ≲2.0 × 1012 ... ... ≲7 × 10-13 g ≲5 × 10-13 g

Notes.

(a)

The limits are estimated over the velocity ranges listed in Col. (2).

(b)

Using the high temperature ortho-to-para (OPR) limit of 3 for NH2.

(c)

Using OPR(NH3) = 0.7 (Persson et al. 2012).

(d)

NH = 2N(H2) + N(H) = 4.3 × 1022 cm-2 (Garwood & Dickey 1989; Monje et al. 2011).

(e)

NH = 2N(H2) + N(H) = 5.6 × 1022 cm-2 (N(H) from Winkel et al. (in prep.) and N(H2) from Godard et al. 2012).

(f)

NH ≈ 2 × N(H2) = 5 × 1023 cm-2 in the Sgr B2 (M) molecular envelope (Lis & Goldsmith 1989).

(g)

NH = 2 × N(H2) / 2 = 4 × 1024 cm-2 in the G10.60.4 molecular cloud (Fazio et al. 1978) assuming that NH+ and NH are most likely to be seen in absorption thereby probing half of the total column density that is in front of the continuum source.

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