Deep broad-band optical images were
obtained during 1990-1995. BVRI images of Arp 86 have been
published earlier (Laurikainen et al. 1993) and are not
reported here. Table 1 lists the sample galaxies: if not
otherwise mentioned the data is from the "Third Reference
Catalogue of Bright Galaxies" (de Vaucouleurs et al. 1991).
Other name is given if the galaxy has PGC, NGC, Arp or
Mrk designation. 
denotes the mean revised morphological
type in the RC3 system, and cz is the heliocentric radial
velocity of the galaxy. The observations were carried out
with the 1.5 m telescope of the Observatorio Astronomico
National in Calar Alto, the 1 m Jacobus Kapteyn Telescope
(JKT) and the 2.5 m Nordic Optical Telescope (NOT) in La
Palma, and the 2.1 m telescope in San Pedro Martir (SPM)
in Baja California. In most cases the filters were in the
Cousin's BVRI photometric system, but at NOT Thuan-Gunn
and 
filters, attached to the Stockholm CCD,
were used. We also measured some galaxies without any filter,
designated as bl in Table 3. The log of observations is
given in Table 2, showing the pixel sizes, CCD-fields
and weather conditions for the different observing runs.
In Table 3 we show the filters,
rebinning factors used
while constructing the color maps and the telescopes used.
The integration times were 40-120 minutes in B band,
20-90 minutes
in V and 20-60 minutes in R and I bands.
The Stockholm CCD at NOT 
was non-linear prior to the year 1993,
deviating from linearity about 
. This non-linearity was corrected by
applying an ADU-level dependent correction to each pixel assuming that
the non-linearity occurs after the bias addition.
The empirical relations by Kjeldsen (1990, private communication)
were applied.
After that the standard reduction steps
followed.
If the bias was structureless a constant
value was subtracted, otherwise several bias frames were combined,
smoothed and normalized to the overscan value, when available.
Twilight flat-fields in each filter were taken each night except the
night of the campaign in Calar Alto in 1991 and the
night in 1992,
in which cases the flat-fields of the previous nights were used.
Several integrations in each field were co-added after the alignment
to within a fraction of a pixel using the routines of IRAF. Cosmic
rays and bad pixels and columns were eliminated by the procedures of
IDL and IRAF.
The R- and I-band images of Kar 296 and Arp 298 were saturated in a few
nuclear pixels.
Since we are interested in surface photometry special attention was paid on correcting the sky gradients. In the final images the gradients were in most cases comparable to the sky background noise. In some images the global structure of the flat-field frames differed from that of the science frames and the strengths of the dust rings varied during some nights, probably because of the combined effects of dust in the chip and in the filterwheel: however their locations fortunately remained fixed and therefore could be mostly eliminated. When the galaxy was small compared to the total frame size, the median of the shifted science images was used as a correction frame.
The images of Calar Alto had a charge transfer problem:
the signal levels of the images were dropped by 1-5 ADU's
following bright point-like sources.
This effect was corrected by adding a constant to the
affected parts of the images.
During the campaign of Jan. 1990 two gain factors
were used. To obtain the same
conversion of electrons to ADU's for the stars and
galaxies, the star images were multiplied by a
constant. The estimated error of the correction was 
,
based on measurements of one star, observed using both
gain factors.
For flux calibration the lists of standart stars by
Landolt (1983) and Landolt (1992) were used and 5-10
standard measurements per night in
each filter were obtained. Bias, dark and
flat-fied corrections for the standard stars were done
and the instrumental magnitudes of one observing
run were combined to fit the zero-points and color terms using the
following equations:
where 
and i are
the instrumental magnitudes, 
and I the
magnitudes in the
Cousins system, 
and i1 the
zero-point coefficients, 
and i2
the extinction coefficients, 
and
i3 the color terms and X is the air mass. Two alternative
reductions for v and r are distinguished by primes.
While the zero-points and color terms were
calculated for each campaign,
extinction was measured for each night.
The color terms are small being only slightly larger than the
error estimates of the zero-point coefficients. The mean errors
of the zero-points were 0.04 mag in B, V and I, and 0.03 mag in R.
Flux calibration for the campaigns at NOT prior to 1993 are
complicated by the fact that the standard star magnitudes in the
literature are in the Cousins photometric system, whereas we used
Thuan-Gunn and filters. In that case
transformations from Cousins to Thuan-Gunn system were applied
for the Landolt standard stars using the transformation equations
by Schombert et al. (1990):
For the observations of Arp 82 we had only one night in SPM so that
it was not possible to do similar reduction as for the other galaxies.
Instead, the flux calibration was performed by one standard star.
Extinction was
measured in B-band and approximated in the other bands by applying the
average 
-extinction curve for SPM.
The total B-magnitudes and B-V, V-R and R-I color indices, measured by synthetic aperture photometry, are shown in Table 4, together with the B-magnitudes by de Vaucouleurs et al. (1991). Bright stars were eliminated and the few saturated pixels in the R- and I-images of Kar 296 and Arp 298 were replaced by the mean of the nearest pixels. The zero points of one of our campaigns (CA 1992) were shifted by 0.6 magnitudes in comparison with de Vaucouleurs et al., which has been taken into account in the magnitudes of Table 4. After this correction our measurements are in good agreement with the measurements by de Vaucouleurs et al.. The magnitudes are measured typically to the surface brightness of 26- 27 mag/arcsec2.
The color maps B-V, B-R, V-R, B-I, V-I and R-I were constructed by
accepting only pixels above the 3
level. The selection was
made before converting the digital units to instrumental magnitudes
and in construction of the color maps both images had to satisfy the
criterion simultaneously in each pixel. In a few cases the sky
gradient was larger than the 3 level in which case the sky
gradient was used as a selection limit for the accepted pixels. The
images were rebinned (see Table 3) in order to reach a limiting
surface brightness of about 
.
The R-band image and the
color maps B-V and R-I (if not otherwise mentioned)
are shown in Fig. 2.
A check of the reliability of our color images was made
by comparing our B-I map for NGC 5905 with the map by Wozniak
et al. (1995): we measure the same mean B-I = 2.3 along the dust lanes
in the bar. Also the morphological characteristics of the two color
maps are identical.
Figure 2: Direct R-band image and the color indice maps R-I and B-V
(if not otherwise indicated in the figure). The R-band frame is the cleaned
image displayed in a logaritmic scale. The color indice maps are
constructed from rebinned images, accepting only pixels above the
3 level: the rebinning yields a limiting surface
brightness of 
. In all images North is up and Est
is left. Vertical bars denote the angular scale and the absolute linear
scale, calculated as in Fig. 1
| Galaxy | RA | DEC | cz | 2 | Other name | ||||||||
| (1950) | (1950) | ||||||||||||
| [h m s] | [ ] |  | |||||||||||
| Arp 70 | 01:20:41 | 30:31:25 | 104941 | .S?.... | PGC 5085 | ||||||||
| Arp 74 | 02:05:17 | 41:14:33 | 55431 | .SXT5.. | PGC 8161 | ||||||||
| Kar 64 A | 02:18:24 | 39:08:51 | 7465 | .SAS3P. | PGC 8961, Arp 273 | ||||||||
| Kar 64 B | 02:18:27 | 39:07:43 | 7335 | .SBS1P. | PGC 8970 | ||||||||
| Kar 125 A | 07:06:14 | 20:40:58 | 52271 | .P..... | PGC 20259, NGC 2341 | ||||||||
| Kar 125 B | 07:06:21 | 20:43:03 | 52761 | .S...P. | PGC 20265, NGC 2342 | ||||||||
| Arp 82 | 08:08:13 | 25:21:19 | 4079 | .SAR5P. | PGC 22957, NGC 2535 | ||||||||
| 08:08:16 | 25:19:46 | 4142 | .SBT5P. | PGC 22958, NGC 2536 | |||||||||
| Kar 168 A | 08:39:53 | 14:27:58 | 1988 | .S..1.. | PGC 24464, Arp 89, NGC 2648 | ||||||||
| Kar 168 B | 08:40:00 | 14:27 | 2166 | PGC 24469 | |||||||||
| Kar 179 A | 08:53:06 | 52:17:51 | 4098 | .S?.... | PGC 25130 | ||||||||
| Kar 179 B | 08:53:22 | 52:15:33 | 3778 | .SB.2*. | PGC 25142, NGC 2692 | ||||||||
| Kar 203 A | 09:23:30 | 68:37:43 | 3698 | .SBS8P. | Arp 300a, Mrk 111,PGC 26849 | ||||||||
| Kar 203 B | 09:23:43 | 68:38:21 | 3874 | .SXS5. | Arp 300b,PGC 26864 | ||||||||
| Kar 296 A | 11:37:33 | 15:36:17 | 32991 | .SXT3*P | PGC 36197,Arp 83a, NGC 3800 | ||||||||
| Kar 296 B | 11:37:37 | 15:37:11 | 33121 | .SBS3*P | PGC 36193,Arp 83b, NGC 3799 | ||||||||
| Arp 87 | 11:38:08 | 22:42:18 | 7050 | .SXT5*P | PGC 36227, NGC 3808 | ||||||||
| 11:38:08 | 22:43:22 | 7189 | .I.O.SP | PGC 36228, NGC 3808A | |||||||||
| Kar 302 A | 11:46:01 | 48:59:20 | 944 | .SXT5*. | PGC 36875, NGC 3893 | ||||||||
| Kar 302 B | 11:46:19 | 48:57:10 | 869 | .SB.O*P | PGC 36897, NGC 3896 | ||||||||
| Kar 331 A | 12:18:55 | 06:55:53 | 4227 | .L..... | NGC 4296,PGC 39943 | ||||||||
| Kar 331 B | 12:18:54 | 06:56 | 4046 | SO | |||||||||
| Arp 183 | 13:32:38 | 31:39:00 | 49621 | .S..3.. | PGC 47867 | ||||||||
| Arp 36 | 13:31:57 | 31:40:53 | 50171 | .SB?... | PGC 47808 | ||||||||
| Kar 404 A | 13:56:25 | 37:41:51 | 3427 | .SBS3P. | PGC 49739, NGC 5394 | ||||||||
| Kar 404 B | 13:56:30 | 37:40:05 | 3505 | .SAS3P. | PGC 49747, NGC 5395 | ||||||||
| NGC 5905 | 15:14:03 | 55:42:06 | 33901 | .SBR3.. | PGC 54445 | ||||||||
| NGC 5908 | 15:15:23 | 55:35:37 | 33061 | .SAS3*/ | PGC 54522 | ||||||||
| Kar 471 A | 15:42:36 | 41:15:00 | 9480 | .S..... | PGC 55913,Mrk 489,NGC 5992 | ||||||||
| Kar 471 B | 15:42:43 | 41:16:33 | 9565 | .SBR3*. | PGC 55918, NGC 5993 | ||||||||
| Arp 218 | 15:51:18 | 18:45 | .SXS4.. | PGC 56314 | |||||||||
| Kar 523 A | 17:44:18 | 35:35 | 7081 | ||||||||||
| Kar 523 B | 17:44:30 | 35:35:20 | 6734 | .SB?... | PGC 60829, NGC 6447 | ||||||||
| Kar 538 A | 19:11:53 | 73:19:30 | 7510 | .SB?... | PGC 62864, NGC 6786 | ||||||||
| Kar 538 B | 19:12:00 | 73:19 | 7555 | .S?.... | PGC 62867 | ||||||||
| Arp 298 | 23:00:44 | 08:36:19 | 4846 | .PSXT1. | PGC 70348, NGC 7469 | ||||||||
| 23:00:47 | 08:37:26 | 4894 | .SAR6P | PGC 70350 | |||||||||
| Arp 86 | 23:44:33 | 29:12:22 | 51631 | .SXT4.. | PGC 72387,NGC7753 | ||||||||
| 23:44:27 | 29:10:52 | 50721 | .I.O*. | PGC 72382,NGC7752, Mrk1134 | |||||||||
|
|
is mean revised morphological type in the RC2 system.
| Date | Telescope | Pix. size/chip size | seeing | Comment |
| 1990 Jan. 1-5 | NOT, 2.5 m | 0.''20/512 
512 | 0.9-1.4 | photometric |
| 1990 Feb. 24-27 | NOT, 2.5 m | 0.''20/512 512 | 0.7-2.4 | photometric |
| 1991 Jan. 7 | JKT, 1.0 m | 0.''30/385 585
| partly photom. | |
| 1991 July 16-18 | NOT, 2.5 m | 0.''20/ 512 512 | 0.6-1.0 | non-photom. |
| 1991 Aug. 31, Sep 5 | Calar Alto, 1.5 m | 0.''32/ 1024
1024 | 1.4-2.2 | photometric |
| 1992 Feb. 5-12 | Calar Alto, 1.5 m | 0.''32 /1024 1024 | 1.1-1.7 | partly photom. |
| 1993 Apr. 13-14 | NOT, 2.5 m | 0.''20/512 512 | 0.6-1.3 | partly photom. |
| 1993 Nov. 18-20 | NOT, 2.5 m | 0.''14/1024 1024 | 1.0-4.0 | non-photom. |
| 1995 Jan. 31 | SPM, 2.1 m | 0.''30/ 1024 1024 | photometric | |
|
|
| Galaxy | Filters | Rebin | Telescope |
| Arp 70 | BVRIbl | 1 | NOT, Nov. 1993 |
| Arp 74 | BVRIbl | 1 | NOT, Nov. 1993 |
| Kar 64 AB | VRI | 3 | Calar Alto, Feb. 1992 |
| Kar 64 A,B | B | 1 | NOT, Nov. 1993 |
| Kar 125 AB | BVRI | 4 | NOT, July 1991 |
| Arp 82 AB | BVRIbl | 1 | SPM, Jan. 1995 |
| Kar 168 AB | BVRI | 2 | Calar Alto, Feb. 1992 |
| Kar 179 A | BVRI | 1 | NOT, Nov. 1993 |
| Kar 179 B | BVRIbl | 1 | |
| Kar 203 A |  | 1 | JKT, Jan. 1991 |
| Kar 203 B | V | 1 | |
| Kar 296 AB | BVRI | 3 | NOT, Jan. 1990 |
| Arp 87 | BVRI | 3 | Calar Alto, Feb. 1992 |
| Kar 302 A | RI | 4 | Calar Alto, Feb. 1992 |
| Kar 302 B | BVRI | 3 | |
| Kar 331 A | | 2 | NOT, July 1991 |
| Kar 331 B | | 2 | |
| Arp 183 | | 2 | NOT, Apr. 1993 |
| Arp 36 | | 1 | NOT, Apr. 1993 |
| Kar 404 AB | BVRI | 4 | Calar Alto, Feb. 1992 |
| NGC 5905 | BVRI | 3 | Calar Alto, Aug. 1991 |
| NGC 5908 | BVRI | 1 | |
| Kar 471 A | | 2 | NOT, July 1991 |
| Kar 471 B | | 1 | |
| Arp 218 AB | | 2 | NOT, Apr. 1993 |
| Kar 523 A | | 2 | NOT, July 1991 |
| Kar 523 B | | 2 | |
| Kar 538 A | B | 5 | NOT, July 1991 |
| Kar 538 B | B | 7 | |
| Arp 298 AB | BVR | 2 | Calar Alto, Aug. 1991 |
| Galaxy |  |  | B-V | V-R | R-I | ||||||||
| Arp 70 A | 14.77 | 0.95 | 0.61 | 0.38 | |||||||||
| Arp 70 B | 16.13 | 0.99 | 0.51 | 0.54 | |||||||||
| Arp 74 A | 14.76 | 0.96 | 0.57 | 0.55 | |||||||||
| Arp 74 B | 17.40 | 1.24 | 0.56 | 0.52 | |||||||||
| Kar 64 A | 13.58 | 13.42+0.13 | 0.47 | 0.14 | 0.26 | ||||||||
| Kar 64 B | 14.92 | 15.08+0.13 | 0.68 | 0.20 | 0.34 | ||||||||
| Kar 125 A | 12.90 | 12.7+0.30 | 0.77 | 0.59 | 0.45 | ||||||||
| Kar 125 B | 13.77 | 13.8+0.30 | 0.89 | 0.73 | 0.32 | ||||||||
| Arp 82 A | 13.30 | 13.19+0.18 | 0.68 | 0.51 | 0.65 | ||||||||
| Arp 82 B | 14.81 | 14.75+0.18 | 0.62 | 0.44 | 0.60 | ||||||||
| Kar 168 A | 12.60 | 12.74+0.18 | 0.64 | 0.76 | 0.12 | ||||||||
| Kar 168 B | 15.16 | 15.40+0.20 | 0.30 | 0.49 | 0.16 | ||||||||
| Kar 179 A | |||||||||||||
| Kar 179 B | 14.41 | 14.18+0.19 | 1.21 | 0.49 | |||||||||
| Kar 203 A | 13.832 | 0.29 | 0.41 | ||||||||||
| Kar 203 B | 14.212 | ||||||||||||
| Kar 296 A | 13.56 | 13.5+0.2 | 0.80 | 0.47 | 0.50 | ||||||||
| Kar 296 B | 14.58 | 14.7+0.2 | 0.69 | 0.35 | 0.41 | ||||||||
| Arp 87 A | 13.86 | 0.53 | 0.45 | 0.17 | |||||||||
| Arp 87 B | 15.23 | 0.42 | 0.74 | 0.03 | |||||||||
| Kar 302 A | 10.493 | 0.35 | |||||||||||
| Kar 302 B | 13.24 | 0.55 | 0.04 | 0.50 | |||||||||
| Kar 331 A | 13.53 | 13.66+0.18 | 0.81 | 0.53 | 0.73 | ||||||||
| Kar 331 B | 15.42 | 0.94 | 0.40 | 1.15 | |||||||||
| Arp 183 | 14.61 | 14.4+0.2 | 0.44 | 0.54 | 0.86 | ||||||||
| Arp 36 | 15.42 | 0.40 | 0.20 | 1.04 | |||||||||
| Kar 404 A | 12.54 | 12.65+0.13 | 0.56 | 0.75 | 0.60 | ||||||||
| Kar 404 B | 13.84 | 13.62+0.18 | 0.50 | 0.69 | 0.49 | ||||||||
| NGC 5905 | 12.59 | 12.59+0.17 | 0.77 | 0.42 | 0.69 | ||||||||
| NGC 5908 | 12.96 | 13.01+0.13 | 0.86 | 1.34 | 0.22 | ||||||||
| Kar 471 A | 13.88 | 13.90+0.18 | 0.57 | 0.06 | 0.48 | ||||||||
| Kar 471 B | 14.35 | 14.27+0.19 | 0.64 | 0.40 | 0.41 | ||||||||
| Arp 218 A | 15.28 | 15.35+0.18 | 0.52 | 0.53 | 0.15 | ||||||||
| Arp 218 B | 16.80 | 0.81 | 0.54 | 0.38 | |||||||||
| Kar 523 B | 14.08 | 13.74+0.18 | 0.46 | 0.59 | 0.54 | ||||||||
| Kar 523 A | 15.65 | 0.73 | 0.85 | 0.76 | |||||||||
| Kar 538 A | 14.04 | 13.80+0.19 | 1.604 | ||||||||||
| Kar 538 B | 14.94 | 14.90+0.20 | 1.684 | ||||||||||
| Arp 298 A | 12.94 | 13.0+0.11 | 0.57 | 0.59 | |||||||||
| Arp 298 B | 14.97 | 15.08+0.12 | 0.66 | 0.87 | |||||||||
|
|
