Abstract. -We present the results of an isophotal shape analysis of three samples of galaxies in the Coma cluster. Quantitative morphology, together with structural and photometric parameters, is given for each galaxy. Special emphasis has been placed on the detailed classification of early-type galaxies. The three samples are: i) a sample of 97 early-type galaxies brighter than mB = 17.00 falling within one degree from the center of the Coma cluster; these galaxies were observed with CCD cameras, mostly in good to excellent resolution conditions; ii) a magnitude complete sample of 107 galaxies of all morphological types down to mB = 17.00 falling in a circular region of 50 arcmin diameter, slightly offcentered to the North-West of the cluster center; the images for this and the next sample come from digitized photographic plates; iii) a complete comparison sample of 26 galaxies of all morphological types down to mR = 16.05 (or mB 17.5), also in a region of 50 arcmin diameter, but centered 2.6 degrees West of the cluster center. The reliability of our morphological classifications and structural parameters of galaxies, down to the adopted magnitude limits, is assessed by comparing the results on those galaxies for which we had images taken with different instrumentation and/or seeing conditions, and by comparing our results with similar data from other observers.

Abstract. New colour distributions have been derived from wide field UBV RI frames for 36 northern bright elliptical galaxies and a few lenticulars. The classical linear representations of colours against log r were derived, with some improvements in the accuracy of the zero point colours and of the gradients. The radial range of significant measurements was enlarged both towards the galaxy center and towards the outskirts of each object. Thus, the "central colours", integrated within a radius of 3 , and the "outermost colours" averaged near the µV = 24 surface brightness could also be obtained. Some typical deviations of colour profiles from linearity are described. Colour-colour relations of interest are presented. Very tight correlations are found between the U − V colour and the Mg2 line-index, measured either at the Galaxian center or at the effective radius.

Abstract. The B − R colours distributions (with R in Cousins's system) have been measured in 44 E classified galaxies in the Local Supercluster, from pairs of frames collected by Nieto and co-workers in 1989-91. These are nearly all from the CFHT, and of sub-arsec resolution.Great attention has been given to the effects of unequal PSF's in the B and R frames upon colour distributions near centre; such effects are illustrated from model calculations and from pseudo-colours obtained from pairs of frames taken in the same band but with different seeing conditions. Appropriate corrections were systematically applied in order to derive central colours and inner gradients, although still affected by the limited resolution of the frames.The radial colour distributions have been measured in more detail than usual, considering separately the near major axis and near minor axis regions of the isophotal contours. Azimuthal colour distributions, in rings limited by selected isophotes, were also obtained. Dust "patterns", i.e. patches, lanes, arcs, ..., have been detected and mapped from the colour distributions. An ad hoc dust pattern importance index (or DP II) in a scale of 0 to 3, has been introduced to qualify their size and contrast.We have tried to find evidence of a diffuse dust concentration towards the disk, if one is apparent. Positive results (noted by the dd symbol) have been obtained for disky E's, whenever the inclination of their disk to the line of sight is large enough, and eventually also in the small isolated disks sometimes present in both boxy and disky galaxies.The red central peak occurring in many E-galaxies might be the signature of a central concentration of dust, also in cases where this peak is isolated rather than embedded in some extensive colour pattern. The properties Send offprint requests to: R. Michard Based on observations collected at the Canada-FranceHawaii Telescope and at the Observatoire du Pic du Midi.of the near centre colour profiles have been related to a classification of nuclear photometric profiles into "flat topped" and "sharply peaked" (equivalent to "core-like" and "power-law" in the terminology of Faber et al. 1997).The published here data include the following: . Short descriptions and codes for the characters of the B − R distribution of each object, and comparison to the results of recent surveys.. A table of the mean B − R at the centre and at two selected isophotes, a "core colour gradient" and the usual logarithmic gradient.. Maps of near core B − R isochromes and B isophotes for comparison. Images of the B −R colour distribution are made available in electronic form.

This paper presents morphological type, membership, and U−V color for a sample of galaxies in the Coma cluster direction, complete down to M B = −15.00 mag and extending down to M B = −14.25 mag. We have examined 1155 objects from the GMP 1983 catalog on B and V images of the CFH12K camera, and obtained the Hubble type in most cases. Coma cluster membership for 473 galaxies was derived using morphology, apparent size, and surface brightness, and, afterward, redshift. The comparison among morphologyand redshift-memberships and among luminosity functions derived from this morphologically-selected sample, or by using statistical members or spectroscopic members, all show that the morphological membership provided here can be trusted. For the first time, the morphological classification of Coma galaxies reaches magnitudes that are faint enough to observe the whole magnitude range of the giant types, E, S0, and spiral stages. The data presented in this paper makes our sample the richest environment where membership and morphology for complete samples down to faint magnitudes (M B ∼ −15 mag) are available, thereby enlarging the baseline of environmental studies.

Abstract. PSF far wings have been measured in UBVRi at the 120 cm Newtonian telescope of Observatoire de Haute Provence, during 3 observing runs in 2000-1. The choice of appropriate star fields allowed us to extend the measurements up to a radius of nearly 3 arcmin, and down to a level of about 0.5 × 10 −6 of the central peak. It was found that these wings, farther than a radius of 15 arcsec, do not change with atmospheric seeing, but are dependent on the spectral passband and the time elapsed since the coating of the mirrors. The most prominent spectral effect is the "red halo" occurring with thinned CCDs, but PSF wings in U , B, and R may also stand above the V light wings. All PSF wings were greatly reinforced after 10 months of mirror ageing. The consequences of the far PSF wings for galaxy surface photometry and colorimetry have been studied by convolution of models with the measured PSF. Gray models of E-type objects acquire spurious colour gradients, large enough in V − i to reverse the classically measured ones, and sufficient in U − B or U − V to significantly bias the results. The colours along the major and minor axis are unequally affected for flattened objects. Experiments with a model of the lenticular NGC 3115 show that spurious disk colours may also be introduced. It has been verified that the effects of the "red halo" on V − i colour gradients may be corrected by convolving the frame i with the V PSF and conversely, before measuring the colour distribution. The same is true for the lesser effects in other colours. These "corrections" are made at the expense of resolution and cause further uncertainties in the results.