A λ = 1.3 mm and 2 mm molecular line survey towards M 82

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Table 1

Column densities, rotational temperatures, and fractional abundances of all the observed molecules in the NE lobe of M 82.

Molecule^a	N_mol (cm^-2)	T_rot^b (K)	N_mol/N_C³⁴S

C₂H	(1.3 ± 0.6) × 10¹⁵	20.0 ± 10.0	118.2 ± 60.7
NO	(1.2 ± 0.1) × 10¹⁵	8.8 ± 4.4	109.1 ± 10.7
CH₃CCH^c	(1.2 ± 0.1) × 10¹⁵	31.6 ± 0.1	109.1 ± 10.7
CS (1)^c	(2.0 ± 0.1) × 10¹⁴	5.9 ± 0.1	22.0 ± 1.7
CS (2)^c	(4.2 ± 0.1) × 10¹³	14.7 ± 0.8	...
CH₃OH	(1.2 ± 1.1) × 10¹⁴	26.2 ± 11.7	10.9 ± 11.7
H₂CO	(1.1 ± 0.2) × 10¹⁴	25.5 ± 3.0	10.0 ± 2.7
H₂ S	(6.1 ± 4.5) × 10¹³	20.0 ± 10.0	5.5 ± 5.2
c-C₃H₂	(4.8 ± 1.3) × 10¹³	10.1 ± 1.2	4.4 ± 2.0
HCO	(3.9 ± 2.8) × 10¹³	20.0 ± 10.0	3.5 ± 3.5
SO^†	(3.7 ± 0.5) × 10¹³	20.0 ± 10.0	3.4 ± 1.2
H₂CS	(3.1 ± 2.5) × 10¹³	20.0 ± 10.0	2.8 ± 3.2
HC₃N^c	(2.5 ± 1.2) × 10¹³	24.2 ± 3.9	2.3 ± 1.9
SO₂	(1.2 ± 0.6) × 10¹³	20.0 ± 10.0	1.1 ± 1.3
NH₂ CN	(1.2 ± 1.5) × 10¹³	80.3 ± 52.9	1.1 ± 2.2
C³⁴S	(1.1 ± 0.7) × 10¹³	20.0 ± 10.0	1.0 ± 1.0
CH₃ CN	(6.4 ± 1.2) × 10¹²	32.9 ± 1.6	0.6 ± 0.8
H¹³ CN	(1.7 ± 1.6) × 10¹²	20.0 ± 10.0	0.2 ± 0.9
H¹³CO⁺	(1.3 ± 0.8) × 10¹²	20.0 ± 10.0	0.1 ± 0.8

C¹⁸O^d	(3.5 ± 1.7) × 10¹⁶	20.0 ± 10.0	3181.8 ± 1700.7
CN^e	(2.0 ± 0.5) × 10¹⁴	...	18.2 ± 5.7
HCN^e	(4.0 ± 0.5) × 10¹³	...	3.6 ± 1.2
HNC^f	2.2 × 10¹³	10.0	2.0
CO⁺^g	(6.6 ± 3.4) × 10¹²	20.0 ± 10.0	0.6 ± 1.0
HOC⁺^h	(3.9 ± 1.9) × 10¹²	20.0 ± 10.0	0.4 ± 0.9

Notes.

^(a)

Molecules in boldface are new detections in M 82.

^(b)

Some molecules do not have a wide enough dynamic range in energy to calculate the rotational temperature with precision. For them, we assumed T_rot = 20 ± 10 K (see Sect. 3.4 and Appendix A for details).

^(c)

Some extra detections observed by Aladro et al. (2011) were used. CS shows two components with different column densities and rotational values corresponding to the two fits that result from its Boltzmann diagram. The fractional abundance value is in this case [N_CS(1) + N_CS(2)] /N_C³⁴S. The molecules shown at the bottom of the table were observed by:

^(d)

Martín et al. (2009a);

^(e)

Fuente et al. (2005) (averaged value for the galaxy disk);

^(f)

Hüttemeister et al. (1995) (averaged value for the nuclear zone);

^(g)

Fuente et al. (2006);

^(h)

Aladro et al. (in prep.).

^(†)

Only upper limits were reported until now: SO, and SO₂ by Petuchowski & Bennett (1992), and H¹³CN by Wild et al. (1990).

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