The present data were compared with aperture
photometry available in the literature
by integrating the counts in concentric circular rings
around the galaxy centres to provide curves of growth up to the diameter of
the reference photometry. This operation was made without subtracting
stars from the frames since,
unless otherwise specified, the aperture photometry is generally not corrected
for stellar contamination. Galaxies observed at the 2.2-m telescope in non photometric
conditions and with no aperture photometry available in the literature were re-observed at the
3.5 m telescope.
The growth curve was
used to derive the photometric zero point for
galaxies observed in non photometric periods (as indicated in Table 5), and
provided a general check of the intrinsic photometric accuracy of the current
work. The virtual photometry measurements obtained in this work are consistent in the
average with
the aperture photometry available in the literature (88 measurements):
and
.
The most discrepant measurements are those at small apertures (
)
due to a combination of seeing effects and galaxy centering, which might be
quite inaccurate in the objects with no bright nuclei such as dwarf irregular galaxies.
We estimate that the overall photometric accuracy of our data, including
systematic errors on the zero point determination is 
0.1 mag.
To facilitate comparison with optical data available in the literature,
integrated magnitudes were determined in circular apertures from the
star-subtracted frames to the diameter of the 25.5
mag arcsec
blue isophote as described and tabulated in Table 3.
Using the star-subtracted frames, the surface brightness profiles were
re-determined by averaging the brightness distribution in concentric elliptical
annuli of fixed centre, position angle and ellipticity. The ellipses were
fitted by eye to the K' band 21 mag arcsec
isophotes of the galaxy under
study (for some low-surface brightness galaxies, a weaker isophote had to be used:
the values are given in parentheses in Table 5; see Sect. 4).
This simple technique was preferred to more sophisticated procedures
to be as consistent as possible with the
method we used in optical CCD studies (see Gavazzi et al.
1995a and references therein).
Given the irregular shape of Im and BCD galaxies,
elliptical profiles give just a crude representation of
their real profiles (see Sect. 4).
Starting from an inner ellipse of size comparable with the seeing disk,
a set of annuli, increasing in major axis by fixed amounts was drawn. In each
annulus the total number of counts, pixels and associated statistical
uncertainties were computed following
Gavazzi et al. (1994).
The isophotal major radii (
) in the H and K' bands
were determined from the
azimuthally integrated profiles as the radii at which the surface brightness
reaches 21.5 mag arcsec
. The values of 
given in this work are not
corrected for galaxy inclination.
Magnitudes were derived by integrating the elliptical light profiles up
to the radius corresponding to the 21.5 mag arcsec
isophote (
and
).
Since in some dwarf galaxies 21.5 mag arcsec
is too close to the peak brightness to
measure a meaningful diameter, we also give 
and
. These entries, which are generally less accurate than
and 
because of the higher noise in the data at
the 22.0 mag arcsec
isophote, can nevertheless be fairly well determined in the low
surface brightness galaxies where longer integration times were used.
These magnitudes are observed quantities and are not corrected for extinction.
The photometric parameters determined along elliptical rings are summarized in
Table 5 (only available in electronic form), as follows:
Column 1: VCC name.
Column 2: adopted filter.
Column 3: total integration time per position (in sec); this corresponds
to the product of the exposure time of the elementary integration
(generally 
) 
the number of
(added) elementary integrations.
Column 4: number of frames per galaxy (combined with a
median filter).
Column 5: adopted mosaic, as defined in Sect. 2.2. Some galaxies
(marked 
) were serendipitously
observed in the sky frames of other targets. S indicates large galaxies where
an ad hoc designed mosaic was used.
Column 6: pixel size, in arcseconds: these are 0.64 and 1.61 arcsec/pixel for
the 2.2-m telescope and 0.81 arcsec/pixel for the 3.5-m telescope.
Column 7: photometric quality: galaxies marked ``
'' were observed in
non-photometric periods; diameters and magnitudes are not determined; for
galaxies marked ``r'' the zero-point was
determined using reference aperture photometry.
Column 8: position angle of the galaxy major axis (measured counterclockwise
from N).
Column 9: ellipticity (1-b/a).
Column 10: observed major (
) radius (in arcsec) determined
at the 
magnitude isophote.
Column 11: observed magnitude (
) integrated within the
21.5 mag arcsec
elliptical isophote.
Column 12: concentration index 
, defined as
the ratio between the radii that contain 75% and 25% of 
.
Column 13: observed major (
) radius (in arcsec) determined
at the 
magnitude isophote.
Column 14: observed magnitude (
) integrated within the
22.0 mag arcsec
elliptical isophote.
Column 15: concentration index 
, defined as
the ratio between the radii that contain 75% and 25% of 
.
For galaxies observed at both the 2.2-m and the 3.5-m telescope, Table 5 reports 2 lines. The 3.5-m telescope data refer in fact to the combined images.
Grey-level and contour representations of the K' brightness distribution
of the galaxies studied are given in Fig. 3 (click here) alongside surface
brightness and (where possible) colour profiles.
Table 6 gives the parameters of the differential H and K' band
radial surface brightness
profiles obtained by azimuthal integration along elliptical annuli.
Table 6 (only available in electronic form) is arranged as follow:
Column 1: VCC name.
Column 2: adopted filter.
Column 3: radius (on the major axis) of the elliptical annulus,
in arcseconds.
Column 4: surface brightness at the given radius.