5 The galaxies

In this section we describe the main photometric properties of the galaxies of the sample.

CTS C16.16: It appears in our images as elliptical (see Fig. 1a). Its luminosity profile follows the r^1/4 up to 4 $\hbox{$^{\prime\prime}$ }$. Beyond this limit the profile shows an excess which may be suggestive of a merger scenario. In fact, we observe from our images a group of three small galaxies with very disturbed isophotes towards the SW of CTSC16.16. The biggest one, located to the W, is rather blue with (B-V) = 0.6. Color profiles show that outward of 3 $\hbox{$^{\prime\prime}$ }$ CTSC16.16 does not present a significant gradient, but within this radius both color profiles become bluer. We interpret this result as due to the luminosity of the Gaussian component, which contributes to 30% of the total luminosity. The integrated (B-V) and (V-I) colors are consistent with a dominant stellar population typical of an early type galaxy. From the absolute blue magnitude of CTSC16.16 ( M_B=-20.36) and its dimension ( $r_{\rm eff} = 2$kpc) we conclude that this object is a compact elliptical galaxy.

CTS G03.04: It is a ringed SO galaxy (see Fig. 1b). Besides the ring, shells and plumes are also observed in our images. Despite its morphological classification, CTSG03.04 has rather blue integrated colors [ (B-V)=0.80, (V-I)=0.88)], quite similar to those of an early spiral (Sa). We suggest that such colors may mostly be due to the AGN and disk luminosities. In fact, the blue disk luminosity contribution is almost a factor of 2 larger than that of the bulge and the AGN contributes with almost 20% of the total galaxy luminosity. Color profiles show that the disk becomes important from 6 $\hbox{$^{\prime\prime}$ }$ outwards. Inwards, the gradient becomes blue. The profiles also become very blue towards the galaxy center, where the Seyfert nucleus dominates. A small galaxy, with (B-V)=0.81, is located at 31 $\hbox{$^{\prime\prime}$ }$ to the west ofCTS G03.04.

Figure 4: H$\alpha$ line emission image of ESO 025-G032. North is on top and East to the left. The lower left bar represents 15'' and the corresponding projected scale in kpc is also indicated.

CTS A08.12: This object appears in our images as an E2 (see Fig. 1c) but according to its luminosity profile, we classified it as SO due to the presence of a disk that accounts for 50% of the bulge luminosity. In order to obtain a satisfactory fit to the luminosity profile the disk needed a cutoff radius at about 3 kpc. The integrated colors are similar to a dominant stellar population of an E galaxy. The B-V profile shows a blue gradient that begins at $r = 6\hbox{$^{\prime\prime}$ }$ outwards due to the presence of this disk. However, the V-I profile shows a red gradient with a crescent radius. The most external isophotes of CTS A08.12 are rather disturbed, probably by the presence of three small galaxies located at 9 $\hbox{$^{\prime\prime}$ }$, 17 $\hbox{$^{\prime\prime}$ }$ and 18 $\hbox{$^{\prime\prime}$ }$ to the NE from the nucleus. The colors of these three objects are very similar, with $(B-V)\sim 1.7$. Towards the N, at about 50 $\hbox{$^{\prime\prime}$ }$, there is another SO galaxy that shows very disturbed inner isophotes. A closer inspection of the whole frame field (about 0.09 Mpc²) shows more than 20 galaxies brighter than m_B=18.5 and with (B-V) colors ranging from 1.2 to 1.8. This evidence strongly suggests that CTSA08.12 is located in a group or a poor cluster, not yet identified in the literature.

ESO602-G031: This object is a very luminous SABa ( M_B= -21.28). It has the typical integrated colors of normal spirals (see Fig. 1d). The luminosity profiles are well fitted with the Gauss + bulge + disk components. However, an excess above the fitted profile can be noted at $r=5\hbox{$^{\prime\prime}$ }$ due to the presence of the bar, which is less prominent in the I band. The disk of ESO602-G031 shows a central cutoff radius of about 10 kpc. This feature is well noted in the B-V color map, which is presented in Fig. 5a, showing that the inner 10 kpc are redder ($\sim$0.3 mag) than the outermost regions. The color profiles do not present very pronounced gradients. The outer isophotes show evidence of perturbation, suggesting that the galaxies located to the NE and SW are physical companions. Additional support for this hypothesis can be drawn from the fact that these two galaxies also show signs of tidal interactions.

Figure 5: B-V color maps. North is on top and East to the left. Lower left bar represents 15'' and the corresponding projected scale in Kpc is also indicated. a) ESO 602- G031, b) ESO 025- G 002, c) ESO 354- G 004.

ESO025-G002: According to its B image, we classify it as of SAB type. The galaxy is almost face-on, making evident not only the bar but also a ring located at 6 kpc from the nucleus (see Fig. 1e). Along the ring, we detected several HII regions with fluxes lower than 10^-16 erg cm^-2 s^-1. It is interesting to note that this is the only galaxy of the sample that shows extended H$\alpha$ emission (see Fig. 4). The disk of ESO025-G002 needs a cutoff radius of $\sim$4 kpc to properly fit the luminosity profile. The B-V color map (see Fig. 5b) and the B-V profile (see Fig. 4b) clearly reveal this effect: a reddened inner region with r=5 kpc. The color of this region averages (B-V) = 1.2.

1H1934-063: This galaxy is classified as elliptical in the RC3. However, it shows a very prominent disk and a rather blue color [ (B-V)=0.61]. Moreover, several arms not well developed are easily observed from our B image (see Fig. 1f), leading us to conclude that this objects is of Sb type. Its total radius (r=4 kpc) and its luminosity ( M_B=-18.74) indicate that 1H1934-063 is a rather small galaxy. The luminosity profiles shows an excess over the fitted profile that we interpreted as due to the presence of spiral arms. Luminosity profile decomposition shows that the disk is almost twice as luminous as the bulge. In the B band, the Seyfert nucleus contributes with 20% of the total luminosity of the galaxy. No extended emission nor possible companions are detected.

1H2107-097: We classified this galaxy as S0. From Fig. 1g a disk and a very faint halo that extents up to 18 kpc from the nucleus can be seen. However, it was not possible to trace the luminosity profile up to this radius due the bright star located to the W of the galaxy. The derived magnitude for this object up to a radius of 9 kpc is M_B=-20.68, indicating a rather compact galaxy. The integrated color (B-V)=0.61 is typical of a normal spiral. In the B band, the Seyfert nucleus contributes 30% of the total luminosity. The color profiles show steeper gradients towards the galaxy center. However, in the outermost regions the B-V profile shows a rather constant value while the V-I profile becomes abnormally redder ($\sim$1.8). 1H2107-097 is another sample galaxy that shows a disk with a cutoff radius. The value for this radius is $\sim$3 kpc.

ESO354-G004: This galaxy is cataloged in the RC3 as (R':)SA(rs)b. However, no evidence of any ring structure is observed in Fig. 1h. ESO354-G004 is rather luminous ( M_b=-21.22) and its radius extends up to 20 kpc. The luminosity profiles are well fitted with a bulge and disk components. The disk shows a cutoff at about 10 kpc. This radius coincides with a red [(B-V)=1.1] region that can be observed from its color map in Fig. 5c. This region is also noticeable in the V-I profile. The integrated colors are consistent with an early type stellar population. Signs of tidal interaction are seen in the images. In fact, it is interesting to note that the galaxy located towards the south seems to be connected with ESO354-G004 by a very faint arm. On the other hand, the object located towards the SW does not show any visible connection with the main galaxy but the arms of ESO354-G004 are perturbed in this direction. These two small galaxies have similar integrated colors, $(B-V)\sim0.8$.

MRK509: This galaxy is a very particular object (see Fig. 1i). It is the most luminous and bluest galaxy [ M_B=-22.34, (B-V)=0.15] of our sample. In addition, it shows the largest luminosity contribution of the Seyfert nucleus to the total luminosity ( $L_{\rm Gauss}/L_{\rm total}=0.56$). This fact affects the integrated colors, which are abnormally blue compared with colors of any morphological type. This object is quite well known for being highly variable both in the continuum and emission lines (Peterson et al. 1998). Its relatively small size ($\sim$10 kpc in radius) makes it also a rather compact object. Apparently, it looks as an elliptical (E1). However, the luminosity profile follows the r^1/4 law up to r=6.5 kpc. Beyond this limit, an excess, which amounts 5% of the bulge luminosity is well fitted with a disk profile with a cutoff radius of 8.7 kpc. It is possible that the galaxy located towards the NW of MRK509 at about 3 $\hbox{$^\prime$ }$ be a physical companion. In fact, it has a (B-V)=0.48 and shows rather disturbed isophotes, giving additional support to this idea.

CTSF10.01: This galaxy is of S0 type and shows a prominent disk (see Fig. 1j). From the luminosity profiles we derived a disk luminosity almost twice as large as that of the bulge. It has M_B=-21.99 and a radius of 18 kpc, indicating that it is a compact object. Despite its morphological type, it is also rather blue [ (B-V)=0.67]. Luminosity profiles show an excess respect to the fitting in the range $5{-}8\hbox{$^{\prime\prime}$ }$. This excess is similar in all bands and can be due to the presence of a lens structure.