Mid-IR emission of galaxies in the Virgo cluster - III. The data

We present ISOCAM imaging data at 6.75 and 15 mum for 145 galaxies in the Virgo cluster and in the Coma/A1367 supercluster. Of these, 99 form a complete, optically-selected, volume-limited sample including galaxies in the core and in the periphery of the Virgo cluster, suitable for statistical analysis. 34 of the Virgo galaxies were resolved by ISOCAM: for these objects we present mid-IR images, radial light and colour profiles, as well as effective and isophotal radii, surface brightness and light concentration indices. The mid-IR colours of the target galaxies show a weak trend with the H band luminosity, with values of F(6.75 mum)/F(15 mum) = 1 found generally in massive objects (L-H greater than or equal to 10(10) L-H.), and F(6.75 mum)/F(15 mum) less than or equal to 1 in low- mass (L-H less than or equal to 10(10) L-H.) dwarf galaxies. All early-type galaxies (type less than or equal to S0a) have F(6.75 mum)/F(15 mum) greater than or equal to 1, as expected when the mid-IR emission is dominated by the photosphere of the cold stellar population. The mid-IR, near-IR and visible light concentration indices of bright galaxies are tightly correlated with one another, indicating that the spatial distribution of the mid-IR emitting sources is, to the first order, similar to that of the stars.