**Table 4:** Integrated line ratios in the centre of M 51.
Transitions	Center		NW Arm GMA-1
	Observed	Modelled^a	Observed	Modelled^a
$~{\rm ^{12}CO}$ (1-0)/(2-1)^b	$1.25\pm0.10$	1.28	$1.40\pm0.20$	1.35
$~{\rm ^{12}CO}$ (3-2)/(2-1)^c	$0.78\pm0.23$	0.75	$1.02\pm0.16$	0.87
$~{\rm ^{12}CO}$ (4-3)/(2-1)^c	$0.49\pm0.10$	0.41	$0.44\pm0.08$	0.46
$~{\rm ^{12}CO}$ / $~{\rm ^{13}CO}$ (1-0)^d	$7\pm1.5$	6.7	$8\pm1.5$	8.2
$~{\rm ^{12}CO}$ / $~{\rm ^{13}CO}$ (2-1)^c,d	$6\pm1$	6.9	$8.7\pm1.2$	8.1
$~{\rm ^{12}CO}$ / $~{\rm ^{13}CO}$ (3-2)^e	$12.9\pm1.8$	12.2	$12.5\pm1.7$	13.2
CI/CO(2-1)^c	$0.22\pm0.06$	-	$0.24\pm0.08$	-
CII/CO(2-1)^f	$0.46\pm0.09$	-	-	-

Notes: ^a See Table 5. ^b Ratios estimated from data by Nakai et al. (1994), NRO at 16'' resolution; García-Burillo et al. (1993b), IRAM at 22''. ^c This Paper, JCMT at 21'' resolution. ^d Ratios estimated from data presented by Rickard & Blitz (1985), NRAO 65'', García-Burillo et al. (1993b), IRAM at 22'', Matsushita et al. (1997), NMA at 6''; and Paglione et al. (2001), FRAO at 45''resolution. ^e This Paper; JCMT at 14'' resolution. f. From Crawford et al. (1985) and Stacey et al. (1991), KAO at 55''resolution; consistent with ISO flux (Negishi et al. 2001); JCMT convolved to 55'' resolution.

Source LaTeX | All tables | In the text