The radial colour distributions in Fig. A1 are "regular", with rather flat V-I and sharply decreasing U-V. The azimuthal colour profiles are flat, showing the isochromes and isophotes to be nearly coincident. The colour map of Fig. A1 shows a low contrast central pattern, with a thin arclet (dust?) in coincidence with an isophotal contour. An interesting property of this galaxy lies in the subtle changes of colour associated with the ring structure, which is demonstrated in Fig. 6;
NGC 3098. It presents a boxy bulge and a disk mixed in a spheroidal envelope. The disk is dominant at and farther. Envelope class: thD. There is an inner disk, giving a fist maximum at , and a low contrast ring with the hump near . The q ratio of the disk component according to M 98 leads to an inclination larger than 84;
The radial colour distributions in Fig. 1 are "regular", while the colours are slightly bluer than average. No evidence for dust is seen. The CFHT frames show the majA to be bluer than surroundings for (see Fig. 4), that is in the ring region. Farther out the reverse situation occurs (see Table 10), possibly due to an outwards blueing of the spheroidal component, compared to a disk with small colour gradient;
The radial colour distributions are surprisingly flat. We note that the object is difficult, too large for the field of the available OHP observations. Silva et al. (1989), found the majA slightly bluer than surroundings. From an analysis in terms of a bulge and disk components, they conclude that the disk population is bluer by 0.5 in B-I than the bulge one, a conclusion very dependent upon their model. Our CFHT frames show the inner disk to be redder (see Fig. A3), while farther out the majA becomes bluer than surroundings, (see Fig. 4) in qualitative agreement with Silva et al. observations. A bulge+disk analysis according to the techniques in M 98, suggests that the B-R differences between the two component remain small. The disk is found redder near (inner disk) and bluer for (main disk). The only evidence for dust in NGC 3115 is in the red inner disk, but this might be a population effect.
This nearby galaxy has been much studied spectroscopically: see the survey by Fischer (1996), and the discussion of a central black hole by Kormendy et al. (1996);
The radial colour distributions in Fig. A4 are "regular". The relatively strong reddening towrds the center is due to a high contrast dust pattern within from center (see map in A4). This in turn contains a blue feature, SE from center. Is it a "hole" in the dust, or a region of relatively recent star formation?
The radial colours (see Fig. A5) are "regular". A slightly redder hump in all colour curves appears at , or a majA of , which put it in coincidence with the ring. According to the high resolution map of Fig. A5, the "inner disk" is redder than surroundings: this reddening is found to be less in V-I than B-V, which may rule out an explanation in terms of a dust concentration. NGC 4026 is not symmetric, the eastern side of the bulge being less bright and redder than the western (Figs. 1 and 5), due to rather thin dust throughout the disk, and/or a system of dust features. Finally, this galaxy presents a remarkable contrast between the majA and minA colours far from center (Figs. 1, 2 and Table 10), a phenomenon we have ascribed to an outwards blueing of the spheroidal component as compared to the disk;
An outstanding dust pattern is present (Fig. A6): three lanes of irregular structure can be recognized, with a geometry suggesting that the dust lies in the disk plane. The colour excess locally reaches E(B-V)=0.18 against background. Besides this, the object shows the minA asymmetry, with the S side redder and less bright, farther out than the lanes. The phenomenon described as "blueing of the outer bulge" is also present (Table 10);
There is a small but high contrast central dust pattern, elongated along both galaxian axes. The map of Fig. A7 suggests that the peanut bulge may result from extinction by the overlying dust. Indeed it has been verified from the original frames, that a dust lane crosses the bulge along the minA, slightly S from center, and shows much less contrast in R than in B (no I frame is available). It is our guess that the peanut bulge would not be seen in the K band. The object is very blue compared to others in the sample, specially in the disk, away from the central dusty bulge, and in the U-V colour (Table 8): its stellar population is probably younger than average. The outer isophotes show, to a rather small extent, the blueing of the minA relative to majA noted for several other objects;
The radial colour distributions (Fig. A8) show a red central peak and a gradient above average in all colours. There is evidence in our data for a reddening of the majA compared to surroundings (see B-R map), and for minA asymmetry, the E side being brighter and bluer. A concentration of dust in the disk is proposed;
The radial colours are standard, except for a prominent red peak inwards of . This may be associated with the reddening of the inner disk against surroundings (Fig. A9, Table 10). Besides the object displays a strong reddening of the outer majA, again ascribed to the outwards blueing of the spheroidal component;
The object displays high contrast dust markings nearly along the majA, but slightly displaced westwards. On the other hand there is a general reddening of the eastern side due to dust in the disk. This also produces a well defined minA asymmetry (Table 11);
The colours of this objects are quite flat, except for a very small central red peak (Fig. A12). They are also bluer than for most other S0's.
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