4. Results: V(R), _M(R), M(R)

In Fig. 1 we present the rotation curves of the 25 galaxies for which we have calculated mass models. The results in Fig. 1 (and subsequent figures) can be easily misinterpreted if they are taken at face-value; in the curve of M81, for example, the rotation of the bulge has not been taken into account because of the large non-circular motions found there. Table 1 contains the most important information concerning the interpretation of the results for the individual galaxies.

Figure 1. Rotation curves of 25 galaxies of various Hubble types.

Table 1 is set up in the same way as table l of chapter 2. To facilitate comparison the same sequence of galaxies has been used. In column 1 we give the name of the galaxy, columns 2 and 3 contain notes on the large and small scale deviations from circular motion as inferred from the velocity field and in column 4 we describe some characteristics of the HI distribution. In column 5 we have coded for each galaxy the main types of non-circular motion which influence the rotation curve analysis: A = arms, B = oval distortion, C = warp, D = large scale asymmetry. In a number of cases optical data have been used for the rotation curve in the inner regions. The symbol OR indicates that this has been done; R indicates radio data only. The addition of a U indicates that we consider the determination of the rotation curve in the inner parts unsatisfactory. The reference to the optical information is given in column 5 as well.

We present the resulting curves of _M(R), derived from Nordsieck's method, in Fig. 2, the cumulative mass curves, M(R) are shown in Fig. 3. In table 2 we give the results of the mass models in tabular form. We have included the parameters of the spheroids and disks of Shu et al.'s method which fit the rotation curve best. We also included some of the parameters which we will discuss in detail in the next chapter.

Figure 2. Mass surface density distributions for 25 galaxies.

Figure 3. Cumulative mass, M(R), as function of R for 25 galaxies.

Table 2.

Galaxy		Rox	Mo†	Ho†	Eo†	Vm	R( = 50)
	Mpc	kpc				km s-1	kpc
N3718
M81	3.25	13.0	9.8	11.1	23.1	217.3	11.9
N4151	13.8	19.6	7.6	9.9	8.2	146.3	12.2
N4736	6.0	10.0	5.3	3.8	9.1	186.0	8.5
M31	0.69	29.5	29.4	90.7	79.7	232.9	24.8
N891	13.75	23.6	19.7	46.3	44.2	211.8	19.4
N2841	9.0	36.1	49.7	219.9	185.0	273.0	32.1
N4565	1.5.0	38.4	43.8	190.5	132.9	246.4	29.9
N5383	31.3	26.8	20.6	50.9	41.4	200.7	17.9
N4258	6.6	29.4	19.5	50.1	34.2	187.4	19.5
N5055	8.0	41.1	25.3	80.3	50.1	199.3	17.3
M51	9.7	11.8	7.1	6.6	14.7	203.3	8.7
N7331	14.0	30.3	31.4	105.6	81.1	227.1	26.9
N253
N3198	9.0	25.7	9.2	14.7	9.0	140.0	11.6
N3359
N5033	14.0	35.8	26.9	86.1	58.8	209.1	22.4
N5907	11.5	30.7	26.3	75.8	67.1	225.9	20.1
N7640
N300
M33	0.72	5.4	0.75	0.19	0.27	85.0	4.4
I342	4.0	22.8	12.9	24.1	18.6	169.7	16.1
N2403	3.25	11.7	3.7	2.7	2.6	119.9	9.4
N4244	3.6	12.3	2.7	1.7	1.5	105.8	7.2
M83	8.9	38.5	18.9	48.4	25.3	163.5	16.8
M101	7.2	13.6	9.9	12.6	18.7	194.2	12.7
N6946
N2805
N4631	5.2	9.9	4.2	2.9	4.5	146.4	9.8
N4236	3.25	11.7	1.3	0.60	0.33	71.9	4.7
I2574
N3109	2.2	20.4	0.91	0.45	0.10	45.9	-
HoII
N4449
Galaxy		12.7	12.7	7.5	34.3	232.5	~ 14
distances from references in table 2.1 or with H = 75 km s-1 Mpc-1
x radius of the last measured point on the rotation curve
† units of Mo (mass within Ro), Ho (angular momentum within Ro), and Eo (kinetic energy of rotation within Ro) are 1010 M, 1013 M kpc km s-1, and 1014 M km-2 s-2 respectively.

Table 2. (continued)

Galaxy	m†	A1	A2	A3	B1	B2	B3	M	relative mass in spheroid
		kpc	kpc	kpc				1010 M	% of Mf
N3718
M81	A	0.8	2.8	3.2	1032	284.5	123.9	11.5	2.9
N4151	A	1.2	9.0	12.8	4616	111.1	17.11	15.9	10.0
N4736	A	1.2	5.0	5.0	1322	226.8	50.96	8.9	14.9
M31	A	2.0	15.0	17.0	919.8	109.4	19.99	52.3	12.7
N891	C	14.0		12.6	97.47		26.41	36.1	10.0
N2841	A	10.5	39.3	31.4	248.4	29.45	12.16	124.0	13.9
N4565	A	13.1	39.3	26.2	164.6	20.86	13.69	90.5	13.4
N5383	A	13.7	31.9	22.8	132.2	16.09	12.38	49.5	15.0
N4258	A	6.0	16.0	18.0	79.16	47.07	16.68	40.9	7.7
N5055	A	3.5	19.4	23:2	493.4	78.12	10.58	40.6	19.0
M51	C	4.8		4.2	224.3		80.13	11.8	6.5
N7331	A	8.1	20.4	24.4	226.6	47.64	15.04	83.3	7.8
N253
N3198	D			6.5			39.73	10.3	0
N3359
N5033	A	3.4	10.9	17.0	502.5	120.8	18.69	44.1	9.4
N5907	B	6.7	13.4	11.2	184.9	81.35	31.46	35.6	10.2
N7640
N300
M33	C	1.2		3.5	279.6		45.88	2.1	0.89
I342	B	11.2	23.3	14.8	95.83	26.35	17.48	26.0	11.5
N2403	C	9.5		9.4	73.32		22.39	10.2	6.2
N4244	C	5.2		4.7	64.35		40.13	4.0	2.1
M83	C	16.0		15.0	69.06		16.50	24.4	12.2
M101	C	6.0		7.0	173.2		47.75	19.1	4.7
N6946
N2805
N4631	B	3.0	10.1	8.8	367.5	74.90	23.92	10.5	12.6
N4236	D			6.6			20.50	2.8	0
I2574
N3109	D			10.4			8.26	1.8	0
HoII
N4449
Galaxy	C	1.9		6.5	1170		58.10	22.9	5.7