2 Sample and observations

Continuing the program of Paper I with the same selection criteria, we present here a sample of 42 galaxies of type Sa to Sc, both unbarred and barred, with intermediate inclination, km s^-1, and absolute magnitude $-22.3 \le M_B \le - 18.2$. Among these, 31 have surface photometry from Héraudeau & Simien (1996): hereafter HS96).

Our kinematic observations were secured at the 1.93-m telescope of the Observatoire de Haute-Provence, equipped with the CARELEC long-slit spectrograph. The selected setup provided a wavelength range of $\approx$ 900 Å centered on Mg b, with a pixel size of 1.8 Å and, perpendicularly to the dispersion, 1.2''. The slit width, projected onto the plane of the sky, was 2.2''. The instrumental dispersion was 78 km s^-1. We refer to Paper I for further details on the setup.

In December 1993, February and December 1994, and January 1995, a total of 10 nights of observation allowed us to collect data on the major axis of 42 galaxies. Table 2 (proposed in electronic form only) presents the log of the observations. Typically, two 45-minute exposures were obtained for each object; these exposure times were short enough to prevent the widening of the spectral lines due to flexures within the spectrograph, yet long enough to allow the measurement of kinematical parameters down to surface brightnesses of $\mu_V\simeq$ 21 mag arcsec^-2, with an accuracy for the velocity dispersion of less than 30 km s^-1 for most objects. For NGC 3338, a single spectrum along the minor axis was also obtained. Each night, several template stars of types ranging between G8III and K2III were observed.

As shown in Table 2, the atmospheric conditions were mediocre on average, with a seeing disk between 2'' and 3'' (FWHM) for about half the observations, 3.5'' for nine objects, and up to $\simeq5.5''$ in a couple of extreme cases (incidence on the reliability of the results is discussed in Sect. 6). Care has been taken to match the seeing conditions of the galaxy and star spectra, in order to ensure comparable spectroscopic resolutions.

  

Table 1: Catalog elements and spectroscopic results

$\parbox{17.6cm}{{\em Notes}.\/ Columns (2) to (9) are from the LEDA d... ...weighted bulge velocity dispersion within $0.1 r_{\rm e}$\space (see Sect. 5).}$